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THE SOVIET JOURNAL OF ATOMIC ENERGY VOL. 7 NO. 4

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March 1, 1961
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Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Volume 7, No. 4 March, 1961 THE SOVIET JOURNAL OF OMIC ENEItf.1. TRANSLATED, FROM RUSSIAN CONSULTANTS BUREAU. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 o'utst,g,..ndi'ng new Soviet ?jou_rn KINETICS AND CATALYSIS The firstauthoritative journal specifically designed for those interested (directly or indirectly) in kinetics and catalysis. This journal will carry original theoretical and experimental papers on the kinetics of chemical transformations in gases, solutions and solid phases; the study of intermediate active particles (radicals, ions); combustion; the mechanism of homogeneous and heterogeneous catalysis; the scientific grounds of catalyst selection; important practical, catalytic processes; the et of substance - and heat-transfer proc- esses on thl.. hetics of chemical transformations; methods of calculating and modelling contact apparatus. Reviews summarizing recent achievements in the highly im- portant fields of catalysis and kinetics of .chemical trans- formations will be printed, as well as reports on the proceed-' ings of congresses,-conferences and conventions. In addition to papers originating in the Soviet Union, KINETICS AND. CATALYSIS will contain research of leading scientists from abroad: - Contents of the first issue include: Molecular Structure and Reactivity in Catalysis. A. A. Balandin The Role of the Electron Factor in Catalysis. S. 2. Roginskii - The Principles of the Electron Theory of Catalysis on Semiconductors. F. F. Vol'kenshtein , 'the Use of Electron Paramagnetic Resonance in Chemistry. - V. V. Voevodskii , The Study of Chain and Molecular Reactions of Intermediate Sub- stances in Oxidation of n-Decane. Z. K. Maizus, I. P. Skibida, N. M. Emanuel' and V. N. Yakovleva ,The Mechanism of Oxidative Catalysis by Metal Oxides. V. A. Roiter The. Mechanism of Hydrogen-Isotope Exchange an Platinum Films. G. K. Boreskov and A. A. Vasilevich - Nature of the Change of Heat-and Activation Energy of Adsorption with Increasing Filling Up of the Surface. N. P. Keier Catalytic Function of Metal Ions in a (Homogeneous Medium. L. A. Nikolaev Determination of Adsorption Coefficient by Kinetic Method. 1. Adsorp- tion Coefficient of Water, Ether and Ethylene on Alumina. K. V. Topchie3a and B. V. Romanovskii The Chemical Activity of Intermediate Products in Form of Hydrocar- bon Surface Radicals in Heterogeneous Catalysis with Carbon^ Monoxide and Olefins. Ya: T. Eidus Contact Catalytic Oxidation of Organic Compounds in the Liquid Phase on Noble Metals. I. Oxidation of the Monophenyl Ether of Ethyl- eneglycol to PhenoxyaCetic Acid. I. I. Joffe, Yu. T. Nikolaev and M. S. Brodskii Annual Subscription: $150.00 Is ix issues per year -approx. 1050 pages per volume JOURNAL. OF' STRUCTURAL CHEMISTRY This significant journal contains papers on all of the most important aspects of theoretical and practical structural chemistry, with an emphasis given to new physical methods and techniques. Review articles on special subjects in the field will cover published work not readily available in English. The development of new techniques for investigating the structure of matter and the nature of the chemical bond has been no less rapid and spectacular in the USSR than in the West; the Soviet approach to the many problems of structural chemistry cannot fail to stimulate and enrich Western work in this field. Of special value to all chemists; physicists, geo- chemists, and biologists whose work is intimately linked with problems of the molecular structure of matter. Contents of the first issue include: Electron-Diffraction Investigation of the Structure of Nitric Acid and Anhydride Molecules in Vapors. P. A. Akishin, L. V.' Vilkov and V. Ya. Rosolovskli Effects of Ions'an the Structure -of Water. I. G. Mikhallov and Yu' P. Syrnikov Proton Relaxation in Aqueous Solutions of Diamagnetic Salts. 1, Solu. tions of Nitrates of Group II Elements. V. M. Vdovenko and V. A. Shcherbakov Oscillation Frequencies of Water Molecules in the First Coordination Layer of Ion in Aqueous Solutions. O. Ya. Samilov -- Second Chapter of Silicate Crystallochemistry. N. V. Belov Structure of Epididymite NaBeSi3O;OH. A New Form of Infinite Silicon -Oxygen Chain (band) [Si6O1,]. E. A. Podedimskaya and N. V. Belov Phases Formed in the System Cljromium-Boron in the Boron-Rich Region. V. A. Epel'baum, N. G. Sevast'yanov, M. A. Gurevich and G. S. Zhdanov - Crystal Structure of the Ternary Phase in the Systems Mo(W)- Fe(CO,Ni)-Si. E. I..Gladyshevskii and Yu. B. Kyz'ma , Complex Compounds with Multiple Bonds in the Inner Sphere: G. B. Bokii - Quantitive Evaluation of the Maxima of Three-Dimensional Paterson Functions. V. V. llyukhin and S. V. Borisov Application of Infrared Spectroscopy to Study of Structure of Silicates. I. Reflection Spectra of Crystalline Sodium Silicates in Region of 7.5-15N,. V. A. Flocinskaya and R. S. Pechenkina Use of Electron Paramagnetic Resonance for Investigating the Molec- ular Structure of Coals. N. N. Tikhomirova, I. V. Nikolaeva and, V. V. Voevodskii New Magnetic Properties 'of Macromolecular Compounds with Con- jugated Double Bonds. L. A. Blyumenfel'd, K. A. Slinkin and A.E. Kalmanson - - ' Annual Subscription: $80.00- Six issues peryear - approx. 750 pages per volume Publication in the USSR began with the May-June 1960 issues. Therefore, the 1960 volume will contain four issues-The first of.,these will be available in translation in April 1961. CONSULTANTS BUREAU 227 W. 17 ST., NEW YORK 11, N. Y. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 EDITORIAL BOARD OF ATOMNAYA ENERGIYA A. I. Alikhanov A. A. Bochvar N. A. Dollezhal' D. V. Efremov V. S. Emel'yanov V. S. Fursov V. F. Kalinin A. K. Krasin A. V. Lebedinskii A. I. Leipunskii I. I. Novikov (Editor-in-Chief) B. V. Semenov V. I. Veksler A. P. Vinogradov N. A. Vlasov (Assistant Editor) A. P. Zefirov THE SOVIET JOURNAL OF ATOMIC ENERGY A translation of ATOMNAYA ENERGIYA, a publication of the Academy of Sciences,;of the USSR (Russian original dated October? 1959);. Vol. 7, No. 4 . March, 1961 CONTENTS RUSS. PAGE PAGE Passage of Fast Neutrons Through Lead and Iron. D. L. Broder, A. A. Kutuzov, V. V. Levin, V. V. Orlov, and A. V. Turusova ....................... .......... .. 797 313 On Ml--Transitions From Highly Excited States.` L. V. Groshev and A. M. Demidov ........ 804 321 Growth of Uranium Rods in an Aggressive Gaseous Medium. I.'. V. Batenin, A. N. Rudenko, and. B. V. Sharov . ................................................ 811 329 Experimental Investigation of the Conditions of the Reduction and Precipitation of Uranium by Minerals. R. P. Rafal'skii and K. F. Kudunova ............................ 815 333 Techniques for the Preparation and Identification of Transplutonium Elements. A. Ghiorso ... 819 338 The Neutron Tissue Dose. A. M. Kogan, G. G. Petrov, L. A. Chudov, and P. A. Yampol'skii .. 830 351 LETTERS TO THE EDITOR Behavior of Reactors with Temperature Self-Regulation. V. N. Andreev, O. D. Kazachkovskii, and N. V. Krasnoyarov .................................:......... 841 363 Heat Transfer in Mercury Flow Through Annular Channels. V. I. Petrovichev . . . . . . . . . . . . 844 366 Gamma-Ray Albedo of Cow, Cs137, and Cr51 Isotropic Sources for Some Substances. B. P. Bulatov .................................. .............. 847 369 Distribution of Kinetic Energy of Fragments in Ternary Fission of U235 by Thermal Neutrons. V. I. Mostovoi, T. A. Mostovaya, M. Sovinskii, and Yu. S. Saltykov .......... .... 851 372 Mean Number of Neutrons Emitted from U235 in Ternary Fission. V. F. Apalin, Yu. P. Dobrynin, V. P. Zakharova, I. E. Kutikov, and L. A. Mikaelyan ...................... ... 853 375 Interaction of Fast Nucleons with Nuclei of Nikfi-R Photoemulsion. V. S. Barashenkov, V. A. Belyakov,WangShu-fen, V. V. Glagolev, N. Dolkhazhav, L. F. Kirillova, R. M. Lebedev, V. M. Mal'tsev, P. K. Markov, K. D. Tolstov, E. N. Tsyganov, M. G. Shafranova, and Yao Ch'ing-hsieh ............................... 855 376 Excitation Curves for the Reactions B11 (d, 2n) Ci, Be9 (ct, 2n) Ci B10 (d, n) C11, and C12 (d, n) N13. O. D. Brill'and L. V. Sumin..... 856 377 ....................... . . . Thermodynamics of Uranium Tetrafluoride Reduction by Magnesium. I. M Dubrovin and A. K. Evseev ................................................ 858 379 Disintegration of Hafnium by 660-Mev Protons. A. K. Labrukhin and A. A. Pozdnyakov ..... 862 382. An Autoradiographic Method of Investigating Ink and Pencil Lines on Documents. B. E. Gordon and V. K. Lisichenko ...... ...................................... 864 384 Reflection of Neutrons with Different Energies from Paraffin and Water. A. M. Kogan, G. G. Petrov, L. A. Chudov, and P. A. Yampol'skii ......................... 865 385 Distribution of the Absorption Density of Neutrons in Paraffin. A. M. Kogan, G. G. Petrov, L. A. Chudov, and P. A. Yampol'skii ................................. 867 386 Annual subscription $ 75.00 ? 1961 Consultants Bureau Enterprises, Inc., 227 West 17th St., New York 11, N. Y. Single issue 20.00 Note: The sale of photostatic copies of any portion of this copyright translation is expressly Single article 12.50 prohibited by the copyright owners. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 CONTENTS (continued) PAGE RUSS. PAGE NEWS OF SCIENCE AND TECHNOLOGY International Conference on Cosmic Rays. V. Parkhit'ko ........................ 869 389 -,Ninth International Conference on High-Energy Physics. B.Govorkov ................ 871 391 The Section on Atomic Science and Engineering at the American Exposition in Moscow .... 875 395 [Start-up of LAPRE-2 Reactor .......................................... 3961 Annular Fixed-Field Strong-Focusing Accelerators ............................ 876 396 New Rules for Transporting Hot Materials. A. Shpan' and N. Leshchinskii ............. 879 399 A .New Container for High-Activity Radiation Sources. V. Sinitsyn, N. Leshchinskii, and A. Gusev ............. ....................................... 880 399 Brief Communications .............................................. 881 401 BIBLIOGRAPHY New Literature .. ...... ............... ....................... 882 406 The Table of Contents lists all material that appears in Atomnaya Energiya. Those items that originated in the English language are not included' in the translation and are shown en- closed in brackets. Whenever possible, the English-language source containing the omitted reports will be given. Consultants Bureau Enterprises, Inc. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 PASSAGE OF FAST NEUTRONS THROUGH LEAD ' AND IRON D. L. Broder, A. A. Kutuzov, V. V. Levin, V. V. Orlov, and A. V. Turusova Translated from Atomnaya Energiya, Vol. 7, No. 4, pp. 313-320 October, 1959 Original article submitted January 21, 1959 The present article describes the results obtained in measuring the spatial distribution of fast neutrons, which are emitted from sources of monoenergetic neutrons, with E0 = 4 Mev and E0 = 14.9 Mev, as well as neutrons from atomic reactors, in lead and iron. In order to calculate the space-energy distribution of fast neutrons at large distances from the source, we have developed a method of solving the kinetic equation for media where the neutrons are moderated due to inelastic scattering on nuclei. A The anisotropy of elastic scattering is taken. into account. The energy losses of neutrons in elastic scattering are neglected. Introduction One of the main problems in designing nuclear reactors is the calculation of biological shielding. Materials which contain a mixture of light and heavy nuclei have the best protective properties. Substan- ces with medium and large atomic numbers, for instance, iron, serve as structural materials for screens, reactor vessels, and first shielding layers. Therefore, the study of the spatial and energetic distribution of neutrons in these substances is of considerable interest. Iron is a good moderator for neutrons with E > 1 Mev because of the inelastic scattering on nuclei. In this, the elastic scattering of neutrons with such energies does not play an important role in moderation, how- ever, it materially affects their spatial distribution. Until the present time, little information has been published on neutron distribution in iron and lead. We have performed experiments in measuring the attenuation of fast neutron fluxes in these substances. Experimental Devices Neutron Sources and Media Under Investigation. As neutron sources, we used the reactor of the First Atomic Power Station [2], the VVR experimental nuclear reactor with ordinary water and enriched uranium [3], and a neutron generator yielding neutrons with an average energy (E0) of 4 Mev [reaction D(d, n)He3] and of 14.9 Mev [reaction T(d, n)He4]. Inves- tigations of the shielding properties of lead were conducted on the top shield of the reactor in the First Atomic Power Station. A converter made of uranium 90% enriched with U235, which was 65 mm in diameter and 20 mm thick, was installed at the upper part of a vertical channel reaching the reactor core. The channel was filled with cylindrical graphite rods up to a height of 60 cm from the core level in order to reduce the shooting of fast neutrons from the reactor through the channel. A block composed of lead plates with dimensions of 710 X 710 X 700 mm was placed above the converter. The detectors were placed in horizontal channels which were provided in the block. The spatial distribution of neutrons in iron: was measured in the VVR reactor.t Specimens of the materials under investigation were. placed on a special truck in an experimental recess with dimensions 1720 X 1720 mm. The. measurements were performed for semiinfinite geometry (the source was placed outside the medium under investigation at a certain distance from its boundary, and the detector was placed inside the medium). The minimum distance from the core center to the measurement point was 645 mm. The specimens consisted of Steel-3 slabs with dimensions of 1500 X 1500 mm. Vertical channels 50 mm in dia- meter, where detectors were placed, were provided in the slabs. The unoccupied channels were stopped with Steel-3 plugs. The spatial distribution of neutrons in iron and lead was measured also by means of a neutron gene- rator. Targets of heavy ice (E0 = 4 Mev) and tritium, which was adsorbed by zirconium (B0 = 14. 9 Mev), were in the shape of disks 10 mm in diameter. Iron and lead specimens were in the shape of prisms with S. A. Kurkin collaborated in developing the cal- culation method [1]. t M. B. Egiazarov, V. S. Dikarev, V. G. Madeev, E. N. Korolev, and N. S. Il' inskii collaborated in these measurements. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 dimensions of 710 X 710 X 830 mm. The neutron source was placed inside the prisms at a distance of 150 mm from their front faces. The detectors were placed in vertical channels in the prisms, and the unoccupied channels were stopped with steel or lead plugs. In all experiments, the density of lead was 11. 3 g/ cm3, and the density of steel was 7. 83 g/ cm3. Neutron Detectors. A Th232 fission chamber and the threshold indicators A127(n,p)Mg27, P" (n, P) St", and S32(n, p) p32 were used as detectors of fast neu- trons. The distribution of thermal and epithermal neutrons was measured by means of a fission chamber with U235 The fission chambers consisted of pulse-counting ion chambers; in these chambers, two nickel strips served as electrodes, on both sides of which the 20 30 a 40 50 r, Ti fissionable substance was deposited. The strips were wound into helices 25 mm in diameter and 37 mm long. The layer thickness of the fissionable substance was 2, 5 mg/ cm2, and the over-all amount-of the fissionable substance in the chamber was N 1 g. The fission reaction threshold for thorium was 1. 1 Mev. A check showed that the correction for the influence of y rays and slow neutrons did not exceed 1016 of the magnitude of the effect in all measurements in the thorium chamber. Two types of the threshold indicators P" (n, P) Si31 (reaction threshold: 1.5 Mev), A127 (n, p) Mg27 (reaction threshold: 2. 1 Mev), and S32 (n, p) P32 (reaction threshold: 1. 5 Mev) were used: disk-shaped indicators with a diameter. of 15 mm and a thickness of 3 mm (for small distances from the source) and indicators in the shape of hollow cylinders with an outside diameter of 35 mm, a length. of 46 mm, and a wall thickness of 3 mm (for large distances from the source). During measurements, all indicators were enclosed in cadmium cases, which had a thickness of 0.6 mm. The activity of the indicators was determined by means of devices with 13 counters. In order to reduce the background, the 6 counter for cylindrical indicators was connected to an anticoincidence cir- cuit with y counters, which were surrounding the S counter. The effect was separated by analyzing the decay curves for the activity of the indicators. Experimental Figures 1 and 2 show the results of measurements for iron, which were obtained with neutron sources with average energies of 4 and 14.9 Mev and with the VVR reactor. The magnitudes of neutron fluxes, 30 40 b 50 . 60 r, c-n Fig. 1. Spatial distribution of fast neutrons in iron' a) Eo = 4 Mev; b) Ep = 14.9 Mev. Infinite geometry; 0) measurement by means of a fission chamber with Th232; o)measurement by means of the P31(n, p) Si31 indicator; A) measurement by means of the S32 (n, p) PS2 indicator; 1), 2), 3) and 4) theoretical curves for Th, P, S, and Al , respectively. 10 1 0 .,. 70 80 Fig. 2, Spatial distribution of neutrons from the VVR reactor in iron, measured by means of fission. chambers with Th32 and U. Semiinfinite geometry: a) thermal neutrons; O) fast neutrons. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 10 ' e -0r 30 b 40 50 60 r cm 50 60 70 r, cm Fig. 3. Spatial distribution of fast neutrons in lead: a)Eo-= =4 Mev; b) E0=14.9 Mev. Infinite geometry; 0) meas- urement by means of a fission chamber with Th232; e) by means of the Pal (n, p) SO' indicator; A) by means of the S32 (n, p) P32 indicator; A) by means of the A127 (n, p) Mg27 indicator; 1), 2), 3) and 4) theoretical curves for Th, P, S, and Al, respectively. multiplied by the square of the distance from the detector. to the source in the case where the fluxes were measured by means of threshold detectors and by.the square of the distance from the detector to the core center in the case where the measurements were performed in the reactor, are plotted on the axis of ordinates. The measurement results for lead are shown in Figs. 3 and 4. The curves in these diagrams were plotted with respect to the results obtained in calcu- lations for an isotropic point source. The calculation method is explained below. The experimental data obtained in measurements with a converter in the reactor of the First. Atomic Power Station were converted for an isotropic point source Theory Consider an infinite homogenous medium contain- ing an infinite flat isotropic source of monoenergetic neutrons with an energy Eo. If we neglect the slowing down of neutrons in elastic scattering and if we consider the inelastic scattering as isotropic, we can write the kinetic equation O(z, E) for the density of neutron collisions in the following form: ?%a T d9ttr(z,.E, t')q(E, ?o)+ Ee + 4n S 0 (z, E') G a n Fin. (E', E) dE' -I- E . gS(z)6(E-E0) 4n (1) where ? is the cosine of the .angle between the direc- tion of the neutron velocity 52 and the z axis, ? o = ST , as is the elastic scattering cross section, Gin is the inelastic scattering cross section, a (E) = as(E) + + Gin(E)+ cc(E)4a c is the absorption cross section), X = 1/ Pa. co(E, Q S2') is the angular distribution of elastically scattered neutrons, ' Fin (E', E) is the energy distribution of neutrons in inelastic scattering, g 4s the source strength, and p is the number of nuclei per cm3 of substance; To(z, E) = '41 (z, ?, E)dc2. We shall further consider that q is always equal to 1. We shall apply the Fourier transformation to (1): 40 r, cm Fig. 4. Spatial distribution of neutrons of the fission spectrum in lead, measured by means of the S32 (n. P) P32 indicator. Infinite geo- metry. IF (z, t, E) = 2~~ ~ (k, t, E) e-11z dk; 1 -ico f9l cp (k, ?, E) = c ll (z, p, E) e';: dz. loo. i Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 For (k, ?, E), we then obtain the equation [1- kk (E) N'p D (k, [t, E) = o (y, (E) (E) S d S2 '(p (E, It,) (D (k, [t', E') + _ + d52' Uin (E' Fin (E', E) (D (k !t', E') dE' + o (E') 4st ' b (E-E0) (3) +q 4n In order to solve (3) we shall use the method of spherical harmonics. Let us apply the Legendre polynomial expansion to 1) (k, ?, E) and cp ( Mo, E): (p (k, [t, E) = 21 n 1 01 (k, E) P, (?); 1=0 tP (?o, E) _ 2l n 1 (p1 (E) Pi (jt0), 1-0 01 (k, E) = ' (k, t, E) P, (N') dQ; cpt (E) = S (p (tt" E) Pi (?o) dQ0. By substituting (4) in (3), we obtain a system of equa- tions for 4)n (k, E): [ 1- os (E) cpn (E) ] cn (k, E) - L. o(L) -k2 (E) It-,-1 (Dn.1(k,E)- 2n+1 -1, ?.(E)2n+1 (?-1 (k, E) Eu o~ njJ;)) ~,, (k, E') Fin (E', E) dE' +q6(E-E,)] s,,,, If we denote qn (k, E)/k0(k, E) by Rn(k, E), we obtain a system of equations for Rn(k, E): -o,(E) q),, (A) Rn(k, E)- - k? (E) 2n+ 1 Rn,1(k, E) - R,,-,(I;, E)=O; ' (6) - lck(E) 2n+1 R? (k, E) =1; n > 0. By solving this system of equations, we find U (E) R, (k, E) = Ri (k, E) . P2 (k, E) V2 (E)-- Y3 (k, E) Y3 (E)-... - Yn-t (E) -Yn (k, E) , 2 (k, E)=k2A,2(E)4rn2 1 ;. I'm (E) =1 os (E) (pm (E); a (E) xm (k, E) = 2mm 1 U (E) Rm+1 (k, E) By using the properties of infinite fractions (see [4]), for the function R(k, E)=y0-R1(k, E)k?,(E) R (k, E) = Vn+, (k, E)-xn (k, E) Vn (k, E) Un+1 (k, E) - Xn (k, E) Un (k, E) ' (9) where V. and Un are polynomials in k2, which satisfy the recurrent relation Wm+1(k, E) = V. (E) wm (E) -- - P. (k, E) wm-1(k, E) with the initial values U0(k, E) = 1, U1 (k, E) =yo (E), VO (k, E) = 0; and V1(k, E)= 1. If, in expanding the scattering indicatrix into Legendre polynomials, we can neglect the nth and the successive terms, i. e. , if we assume that y n = Y n+ 1 = ... =1, then X. (k, E) = Q. `kk (1) )( (Ln 1) kk (E) Qn.1 C 0, (E) ) where Qn is the nth Legendre function of the second kind. For n >> 1, xn(k, E) = i [1 - 1 - k2~2(E)]. By substituting the solution of (8) in (5) for n = 0 and 4 (k, E) = R1 (k, E) (Do (k, E), we obtain the integral equation for (Do (k, E): Eo R~(k,'E) ? S a (T") (Do(k,E')Fin(E',E)dF'+ +QS(E-E?). .(11) In the process of inelastic scattering, the neutrons lose energy by discrete amounts corresponding to the system of nuclear excitation levels. Under these assumptions, (11) assumes the form Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 (U (k L-) - (D~ (k) E+ AEi) X R (k, E) - u o ,, Uin(E..1-AE;.)Fi(E+DE1)+8(E-En)., v (/;'-{-AL:i) where 6Ei is the excitation energy of the ith level, and Fi (E) is the probability that the ith level of a nucleus will become excited in inelastic scattering of neutrons with the energy E. The solution of (12) breaks down into a number of monoenergetic lines: (D? (k, E) =.R (k, Eo) 8 (E - Eo); (I)n (Ic, E1) = oifl (En) F1(Eo) R (k, E't) x x R (Ic, Ej S (E - ER + DE1) etc. The asymptotic solution for each neutron group can be obtained by taking the residues at the poles of each of these expressions: 8 (E-Ed-hoz ~o(z, E()= a 1 ak R(k, Eo) h=h IN (z, E1) = a F 1(Eo) 6 (E - Eo + r e-h (E1) z --F- AE1) 49 1 1 akR(k, E)Ih=h(E,) R (Ic (E1), Eo) --I- e-knz -I a - .R (ko, E1)1 ak R (k, Eo) Ih-ho J E1= Eo - AE1 etc. Discussion of Results By means of the described method, we calcula- ted the neutron fluxes 00(z, E) in an infinite medium for an isotropic flat source. The flux of neutrons with. the energy E in a medium with a point source of unit strength can be expressed in terms of 0 by the equation (DT (r, Ei) = - ? (Ei) [ 21tz ain (, Ei) ] z_r (1)T (r) _ Ei (1)T (1., Es), EI and the flux of neutrons counted by the fission chamber with Th2s2 or by a threshold indicator and normalized to unity for r = 0 will be A=I n=2 n=3 n=4 n 8 Mev region of differential inelastic scattering cross sections and by ?a certain anisotropy of inelastic scattering at high neutron energies. SUMMARY The proposed calculation method makes it possible to find with sufficient accuracy the spatial energy distribution of neutrons in thick layers of substances with comparatively large atomic numbers (for instance, larger than 56) if sufficient data are available on 7 I 0 2 ,0 0 10 20 30 40 Fig. 9. Theoretical spatial distribution of modera-' ted neutrons of different energies in lead. The energy of source neutrons is EQ = 14.9 Mev. Neutron energies (Mev): 0) 14. 9; 1')8; 2') 6; 1.) 4; 2) 3.43; 3) 3.16; 4) 2.32; 5) 1.8; 6) 1.48; 7) 1.22. differential cross sections of inelastic and elastic neutron scattering. Calculations show that, at large distances from the source, the neutron spectrum is enriched with neutrons which are decelerated to a great extent. If the energy distribution is known, multigroup calcula- tions for the shielding can be performed. In conclusion, the authors express their gratitude to Prof. A. K. Krasin, Cand. Tech. Sci. A. N. Serbinov, and scientific collaborator V. A. Romanov for their continued interest in the work and help in organizing the experiments. The authors extend their thanks also to V. G. Liforov, Z. S. Blistanova, and V. S. Tarasenko for their help in conducting the experiments. 1. D. L. Broder, S. A. Kurkin, A. A. Kutuzov, V. V. Levin, and V. V. Orlov,Report No. 2147, submitted to the Second International Conference on the Peaceful Use of Atomic Energy (Geneva, 1958). 2. D. I. Blokhintsev and N. A. Nikolaev, "Reactor construction and reactor theory, " Reports of the Soviet Delegation to the international Conference on the Peaceful Use of Atomic Energy (Geneva, 1955) [in Russian] (Izd. AN SSSR, Moscow, 1955) p. 3. 3. D. I. Blokhintsev and N. A. Nikolaev, "Reactor construc- tion and reactor theory , "Reports of the Soviet Dele - gation to the International Conference on the Peaceful Use of Atomic Energy ( Geneva , 1955) j in Russian ] (Izd. AN SSSR, Moscow, 1955) p.91. 4. A. Wick, Phys. Rev. 75, 738 (1949). 5. L. Cranberg and J. Levin, Phys. Rev. 103, 343 (1956). 6. C. Muelhause, S. Bloom, H. Wegner, and A. Glasoe, Phys. Rev. 103, 720 (1956). 7. M. Walt and H. Barschall, Phys. Rev. 93, 1062 (1954). 8. A. Culler, S. Fernbach, and N. Sherman, Phys. Rev. 101, 1047 (1956). 9. J. Beyster, M. Walt and E. Salmi, Phys. Rev. 104, 1319 (1956). 10. M. Walt and J. Beyster, Phys. Rev. 98, 677 (1955). 11. B. Feld, Phys. Rev. 75, 1115 (1949). 12. D. Hughes and J. Harvey, " Neutron dross sections, " US AEC report BNL-375 (1955). 13. Jagadish Garg and Bechir Torki, Compt. rend. 246, 750 (1958). 14. Yu. S. Zamyatin, E. K. Gutnikova, N. I. Ivano- va, and I. N. Safina, Atomnaya Energiya 3, 540 (1957). *Original Russian pagination. See C. B. translation. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 ON M1-TRANSITIONS FROM HIGHLY EXCITED STATES L. V. Groshev and A. M. Demidov Translated from Atomnaya Energiya, Vol. 7, No. 4, pp. 321-328 October, 1959, Original article submitted May 15, 1959 This article is concerned with the probabilities of Ml-transitions from states created by the capture of thermal neutrons for even-odd and odd-odd emitting nuclei with A from 20 to 60. In the single-particle model, such transitions are forbidden with respect to l . A comparison with the probabilities of El-transistions shows that in even-odd nuclei, the probabilities of forbidden M1-transitions which we observed, did not differ much from the probabilities of I -allowed Ml-transitions for lighter nuclei. In the case of odd-odd nuclei, certain Ml-tran- I M IM, sitions are characterized by a large number of quanta per single neutron capture and a large value of (I MIE1)max In a number of papers [1-4], attempts have recent- ly been made to use the single-particle model in analyzing processes of thermal neutrons capture by nuclei and of the subsequent transition of nuclei into lower states. Such a model explains certain irregula- rities in y -ray spectra from the (n, y) reaction. In particular, within the framework of this model, it is easy to explain the correlation of intensities of El- transitions from the initial state created by the capture' of thermal neutrons with the reduced neutron widths of levels to which these transitions are directed, which is observed in nuclei with A from 20 to 60 [4]. There- fore, it is also of interest to use the single-particle model in considering the probabilities of M1-transitions from the initial state in nuclei from the same atomic weight region. Prohibition of the Considered M1-Transitions in the Single-Particle Model. We shall first restrict our analysis to Ml-transitions of even-odd nuclei formed in the (n, y) reaction. In nuclei with A from 20 to 60, the M1=transitions were separated in the following even-odd nuclei: Mgr', Sim, Sss, and Ca41. Since in the given case the thermal neutrons are captured by even-even nuclei, the M1=transitions from the initial state are directed to levels with'1/2 or 3/2+ characteristics. For the majority of such levels, the value I n = 0 or l n = 2 was found from the angular distribution of protons in the (d, p) reaction. The possibility of detecting M1-transitions in nuclei with A from 20 to 40 is connected with the fact that in these nuclei the 2s 1B / - and 1d3 /2 - states of neutrons are not highly excited. From the point of view. of captured neutron transitions, the Ml-transitions in question must pertain to the (ns1 - 2s1 ) or (ns1 -- -- 1d3 ) types, where n > 2. For both /Z neutron 2 804 transition types, the matrix element in the, single- particle model is exactly equal to zero. The Degree of Forbiddenness of Ml-Transitions In order to determine .the degree of forbiddenness of the M1-transitions in question, it is necessary to compare their probabilities with the probabilities of allowed transitions, which are defined by equations of the single-particle model, i. e. , to find the quantity M 12 = I'exp rgDIDO , (1) where D is the density of neutron s-resonances with a given angular moment, and Do is the density of 'single- particle levels (with a given angular moment and parity) for small excitations. In our case, the quantity rexp can be found from the total radiation width ry and the number Iy of y quanta per single neutron capture for the given tran- sition according to the equation rexp = I'y Iy . In this, it is assurnred that the total radiation width is the same for the neutron resonance,, for which the value of ry was found and for the state created by the capture of a thermal neutron. The quantity rB which enters (1) will determine the neutron transition probability found from equations for the single-particle model [5]. Tak- ing into account the motion of the nucleus carcass, we shall accept the following values for neutron transitions: I'B (E1) = 0,021 A21- EY 0_v, . (2) PB (M1) = 0,015 EY ev y (3) Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 TABLE 1. Radiation Widths and Densities of, Neutron s-Resonances of Nuclei with A From 20 to 40. Nucleus Na21 A148 S129 698 Ciao Tres , kev 2 , 9 -- 190 111 -0,14 r1 ev 0,4161 0,24? 9161 25(6] 0,48[7] D, kev 400 [61 50 [8] 500 [6] 20016] 40 [9] where E y is expressed in megaelectron volts. It should be emphasized that the quantity Do has a high degree of indeterminancy. Data on 1 y and D for nuclei with A from 20 to 40 are given in Table 1. These data are very inaccurate, and, in certain cases, it may possibly be wrong. By using data on ry and D for Si29 and S33 and by assum- ing that Do = 1 Mev, we obtain a very rough estimate for I MI 2 The value for I MI 2 is on the average equal to 1.3 for El-transitions, and it is equal to - 0. 2 for M1-transitions. The I MI 2 values for actual M1-transitions are given in Table 2. The degree of forbiddenness of Ml-transitions can be determined also indirectly, namely, by comparing their probabilities with the probabilities of El-transi- tions in a given nucleus. Table 2 provides data on Ml-transitions from the initial state in even-odd nuclei. This table' provides the characteristics of states between which the transi- tion takes place, and also the quantity IMI?Ml/(IMI1) where the subscript max in I M I E1 signifies that maxi this quantity is taken for the El-transition, which has the highest probability of all El-transitions from the initial state in a given nucleus. All MI-transitions are divided into two large groups, which differ by the magnitude of change in the orbital neutron moment in transition. The M1- transition in Si 29 to the level with an isotropic distri- bution of protons in the (d, p) reaction was additionally separated. The next to last column of Table 2 gives the magnitude of I MI 26 which was found, as was indicated above, from ry and D for Do = 1 Mev. It follows from the last column in Table 2 that if we assume that the probability of the most intensive E1-transition in. a given nucleus is equal to the proba- bility of a transition according to the single-particle model, the value of I MI 2M1 for Mi-transitions will be on the average equal to - 0. 1. For the three transition types separated in the table, this magnitude will be approximately the same if we exclude transi- tions into states with 1 n =O in Ca41, since these states are definitely not pure single-particle 2s 1/2 states. Wilkinson [11] considered the probability ratio of M1- andEl- transitions for light nuclei with A < 20. In this region of atomic weights, M1-transitions mainly take place between p-levels, and consequently these transitions can be considered as 1 -allowed. Unfortunately, it is not possible to compare the pro- babilities of El- and Ml-decays of the same state in light nuclei, as we did in the case of disintegration of a state created by the capture of thermal neutrons. The reason for this is either the insufficient investiga- tion of y -ray spectra or the equal parity of low levels in light nuclei. Therefore, a comparison of probabili- ties of El- and M1- transitions can be done only for different states of light nuclei. T According to [11], by taking into account the- of the nucleus carcass and for D = Do, we movement obtain for the average values: IMIEi=0,15 H IMIM1=0,15,. and IMIMi/I M1Er?1... If we further assume that the matrix elements of El-transitions in nuclei with A < 20 and with A from 20 to 40 do not differ much among themselves and if we consider that we are comparing the I MI 2M1 values with the maximum value of I M 12E1, we can arrive at a qualitative conclusion that the probabilities of forbidden M1-transitions and of the l -allowed M1-tran- sitions in light nuclei, which we have observed, do not differ to a great extent. Causes of Prohibition Removal In heavy nuclei with odd atomic weights, a large number of forbidden MT-transitions with .w , 2"between lower levels is observed. Experimental data on these transitions are considered in more detail in the Appendix. Possible causes of prohibition removal for such M1-transitions were studied in [12-18]. In particular, the following factors were considered: 1) interaction through the exchange of charges and spins between two'. nucleons; 2) a spin-orbital connection; 3) connection between nucleons and nucleus surface oscillations; 4) an admixture of other nucleon configurations in, a given single-particle state. We consider that the 1/2-,. 1/2+ transitions are pure Ml-transitions, since an admixture of E2-transitions can be expected only in the case where M1-transitions are strictly forbidden or if the probabilities of E2-transitions are greatly augmented due to collective effects. From the analysis that we performed, it follows that the. , forbiddenness of MI-transitions is small, and that the observed iprobabilities of E2-transitions correspond to single-particle evaluations [10]. t Wilkinson [11] did not consider separately nuclei with different parities of Z and N numbers, since he did not observe sharp differences in I M 12 for different categories of nuclei. El- as well as M1-transitions,. which have been systematized by Wilkinson, can ob- viously contain various prohibitions (for more details, see [11]), however, we shall abstract them for the mo- ment and consider only the l -prohibition. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 TABLE 2. Ml-Transitions of Even-Odd Nuclei from the Initial State J of Final state charac- teristics E ?" 1 IM12 M1 Transition type Nucleus inttial Mev " 7' IMInt1 state E, Mev J'~ I ~n 2 N(1E1) max Mg25 1/2* 0,58 1/2* 0 6,74 2,6 -- 0,1 A1,t~0 Mg 25 1/2* 2,56 1/2* 0 4,77 1,3 -- 0,12 Si29 1/2* B.S. * 1/2* 0 8,47 2 0,04 0,025 S33 1/2' 0,84 1/2* 0 7,80 2,6 0,47 (sl, -si/a) Ca41 1/2* 2,68 1/2* 0 5,70 1,4 - 1 Ca41 1/2* 3,40 1/2* 0 4,9!. 3 1,5 Aln=2 Mg25 1/2* 0,98 3/2* 2 6,36 4,3 - 0,2 M925 1/2* 2,81 3/2* 2 4,52** 1.4 10 and range R>3.74 mm (g-particles); the sub- script b denotes data on particles with I> 1.4 Io and R 1536. Heat of evapora- tion OHev *The entropies of conversion were calculated from the formula AS con = E Hcon/ Tcon? The heat capacity equation may be found by calculation, starting from the known heat capacity of UF4 at 300 K (C P, = 117.81 joule/ mole deg = 28.16 cal/ mole ? deg [4]) and assuming that the increase in heat capacity with temperature is linear [2] and that the heat capacity of UF4 at the melting point is 7.25 cal/deg ? g ? at. or 36:25 cal/mole- deg. According to [7]. In this case,the equilibrium constants of the reac- tion at different temperatures may be determined from the equation of the reaction isotherm AF? = -4,576 T lg K, AF?=--4,576T]g 9 - PMg where PMg is the equilibrium pressure of magnesium vapor. The change in free energy of the reaction OFZ for different temperature intervals is determined by the Gibbs-Helmholtz equation: 298 \ T OFT AH29e - \ ACpdT )-}-S ACPdT- 298 T ---T (AS299 - A7n dT) - T 7, dT, 298 A1129A- ACndT=AH(0, Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 TABLE 2. AF0 of the Reaction UF4 + 2 Mg = U + 2 MgF2 for Various Temperature Ranges, According to (2) Temp. range, ?K 298-923 923-938 938-1045 1045-1309 1309-1376 1376-1406 1406-1536 1536-1690 * Boiling point of UF4 [4]. - 85 682+20,83T+0,01. 10-3 T2 -1, 819T1gT+2,157.105T-1 -86 678-13,67T-2,44.10-3T2+2,26.105? T-1-{-10,931TIgT - 89 098,6+33,16T+1,63-j0-3T--+2,66- 105 ? T-1- 5 ,169T1gT -86 728,6+22,83T1-1,63.10-3T2-12,66.105?T-1-2,499TIgT -85 871,6-48,76T-2,7.10-3T2-[2,66.105?T-1-{-22,088TIgT -158485,6+49,2T-2,7.10-3T2 ;-2,66.105?T-1-1-7,688T1gT --157 694,3+68,77T-2,7.10-3712+2,66-105- T-1-1-1 , 294T 1gT -140 658,3+137,05T-24, 88T]gT . 298 ( AC., AS2s8- 1 T- dT-4Scoi, rT AFTAHco>-+ - ACpdT- TASco, - T ACp -T dT, o In determining the change in free energy of the reaction, the following phase transitions are considered [2]: 1) the fusion of magnesium at 923? K; 2) the tran- sition of a-uranium into 13 -uranium at 938? K; 3) the transition of 13 -uranium into y -uranium at 1045? K; 4) the fusion of UF4 at 1309? K; 5) the boiling of mag- nesium at 1376? K; 6) the fusion of uranium at 1406? K; 7) the fusion of MgF2 at 1536? K. The data in Table 1 were used for the calculations. The results, calculated in the form of equations for the change in free energy of the reaction, are given inTable 2 and the corrected values of AF?, on the figure. Table 3 gives the numerical values of AF?, Ig K, and PMg for characteristic temperatures and data on other cal- culations of AF? [8] for comparison. As follows from this table and the figure, the reduction of UF4 by magnesium at 1400?C will proceed practically completely toward the formation of metallic uranium and MgF2, since the equi- librium pressure of magnesium vapor at this temperature is very low (0.8 mm Hg). Naturally, the higher the magnesium vapor pressure in the closed reaction vessel (bomb) [9, 10], the faster and more complete will be the reduction over a reaction time, estimated in tens of seconds [101. TABLE 3. Values of AF?, lg K, and PMg for the Reduc- tion of UF4 by Magnesium. Temp., 'K A0?, kcal/mole 6F?,accord- ing8 to data rlkcal/m iF !c P Mg mm Hg 298 -80,1* -82,4 59,0 - 500 -77,8 -79,1 34,0 923 -71,2 - 16,9 - 938 -70,8 - 16,5 - 1000 -69,4 -69,0 15,1 - 1045 -68,7 - 14,4 - 1309 -64,0 - 10,7 - 1376 -62,5 -- 9,93 8,3.10-3 1406 -60,0 - 9 32 1 66.10-2 1500 -54,0 -51,0 , 7,85 , - 1536 -51,7 - 7,35 0,16 1673 -45,6 - 5,95 0,81 1690 --44,8 -- 5,8 0,96 The discrepancy between the given value of AF?, calculated from the equation for A ys-tit, and the value of AF?T, determined from the values of t0?29s of the reaction components(see Table 1), lies with- in the limits of accuracy of the calculations (-'0.65%). With excess magnesium (0.5 - 10%[9, 10]) in the charge, its vapor pressure in the bomb is 8 atmos at 1400? C. T In vacuum remelting (refining) of the crude uranium (^' 1400? C) at a pressure lower. than the equilibrium vapor pressure of magnesium for the reduc- tion, the reaction between crude uranium and slag inclusions of MgF2 proceeds in the reverse direction. In this case the freeing of the uranium from MgF2 will proceed more completely due to volatilization of the magnesium and UF4 obtained (the boiling point of UF4 is 1417? C [4]). t Calculated from the formula lg P = 9.52 -7840/ T- -1.22 lg T [11] (P is the pressure in atmos ). Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 -70 s0 - 30 - 20 100 200 300 400 500 600 .700 800 300 1000 1100 1200 1300 1600 1500 1600 1700 Temperature, ?K Temperature dependence of AF0, ig K,and PMg for magnesium-thermal reduction of UF4. 1. H. Finniston and J. Howe, Progress in Nuclear Energy. Series V. Metallurgy and Fuels, Vol. 1. (Geneva, 1955)[in Russian] (Goskhinizdat, Lenin- grad, 1958) Vol. 9, p. 51. (Pergamon Press, London, 1956). 7. A. Butts, Metallurgical Problems (McGraw-Hill, 2. O. Kubaschewski and E. Evans, Metallurgical New York, 1943) 2nd ed. Thermochemistry (Pergamon Press, London, 1958). 8. A. Lemmon, J. Ward, S. Fisher, Theromdynamics 3. W. Latimer, Oxidation States of the Elements and Their Potentials in Aqueous Solutions [Russian the Reduction of Uranium Compounds to Uranium Metal (US AEC, BMI-550, 1952). translation] (I1, Moscow, 1954). 9. H. Thayer, Report No. 602, presented by the USA 4. F. Rossini, D. Wagman, W. Evans, S.. Levine and I. loffe, "Selected values of chemical theromdy- at the Second International Conference on the Peaceful Uses of Atomic Energy (Geneva, 1958). namic properties," Circular of the Nat. Bur. Standards, US Gov. Printing Off. (1952) p. 359. 10. H. A. Wilhelm, Material of the International Conference on the Peaceful Uses of Atomic Energy 5. L. Brewer, L. Bromley et- al., Thermodynamics of Uranium Compounds. Part I - Thermodynamic (Geneva, 1955) [in Russian] (Metallurgizdat, Moscow, 1958) Vol. 8, p. 199. Tables, Table IV (US AEC, MDDC-1533, 1947). 11. Kh. L. Strelets, A. Yu. Tairs, and B. S. Gulyanitskii, 6. F. G. Foot, Material of the International Con- ference on the Peaceful Use of Atomic Energy Metallurgy of Magnesium [in Russian] (Metallur- gizdat, Moscow, 1950). Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 DISINTEGRATION OF HAFNIUM BY 660-MEV PROTONS A. K. Labrukhin and A. A. Pozdnyakov Translated from Atomnaya 6nergiya,Vol. 7, No. 4, pp. 382-384. October, 1959 Original article submitted February 13, 1959 The aim of the present investigation was to deter- mine the yield of the distintegration products and study some details of the interaction process of 660- Mev protons with hafnium nuclei. The chromatographic separation of the disinteg- ration products the calculation of the a , a+ isotope yields and also the K-capture isotope yield were carried out by methods described in the literature ([1, 2, 3] respectively). The accuracy of the isotope yield determination for K-capture was 50-10016. On the basis of the experimental and interpolated data for all identified elements, curves were construc- ted of the relation between the isotope yields and their mass numbers (Fig. 1). Also, as can be seen, a dome-shaped isotope distribution was observed for the disintegration of hafnium by 660-Mev protons, similar, for example, to the distribution of the disin- tegration products of copper [4]. In the case of copper, however, the dome is situated in the region of nuclear stability, while in the case of hafnium there is a strong shift of the dome toward the neutron-deficient nuclei. Owing to this difference, there is a change in the isotopic composition of the nuclei. In the disin- tegration of hafnium, nuclei deficient in neutrons are mainly produced: 671o of the total disintegration cross section; the share of stable nuclei and nuclei with a surplus of neutrons is 23 and 10%, respectively, while in the disintegration of copper, stable and neutron-deficient nuclei are produced in approximately equal amounts ( " 401.). In the analysis of the isotope distribution vs mass number curves, it should also be noted that there is Fig. 1. Distribution curves for the isotope yields of the rare-earth elements as a func- tion of the mass number. ?) experimental data; 0) interpolated data. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Mean no. of Mean no. of emitted par- evap. particles Ratio of mean Ele- ticles no. of evap. ment z neutr, to mean no. of evap. n p n P Prot. Cu 29 4.8 3.7 2.8 1.7 1.5 Hf 72 13.0 4.1 10.5 2.6 4.0 a shift in the dome-shaped curves from Z=64 in the direction of smaller mass numbers and smaller yields in comparison with the neighboring elements, which apparently may be explained, according to statistical theory, by the influence of closed subshells with Z=64. The value of the total cross section for the pro- duction of isotopes was determined from the curve in Fig. 1. for each element. These values allowed us to establish that the total cross section for the dis- integration process of hafnium nuclei is equal to 1.5 ? 10-24 cm2 (taking into account the hafnium iso- topes, whose total yield was taken as equal to the total yield of lutecium). The value found constituted' 85% of the geometric cross section of hafnium nuclei. It is worth mentioning that in the fraction of lutecium there was found an activity with a period of 4 hr, which could belong to a new isotope Lulls. Assuming that this isotope is B+ active, we calculated its yield. The value obtained corresponds to the broken line extend- ing from the left branch of the lutecium curve in Fig. 1. Curve 1 in Fig. 2 represents the relation between the cumulative isobar yield and the number of emitted nucleons N. As may be seen, the cumulative isobar remains constant for N s 20, and for N > 20 it falls according to the exponential law where the value of the parameter P, determined from the angular coefficient of the curve of Fig. 2 is equal to 0.11.. For isotopes with N > 20, the calculation of the production cross section for a given nucleus- product may be carried out by meams of the semi- empirical formula of Rudstam [6]: To estimate the mean number of neutrons and protons emitted in the disintegration of hafnium, the weighted mean value of these particles was calcu- lated (taking into account the isotopic composition of natural hafnium) with the formula laixi lai where o i is the production cross section for the ith isotope, xi is the number of emitted neutrons or protons during the production of theith. isotope. The results of the calculations are compared in the table with the corresponding quantities for the copper disin- tegration process [41. Moreover, with the help of the data of [7], we were able to estimate the mean number of evaporated neutrons and protons. From the data of the table it follows that in the disintegration of hafnium by 660-Mev protons, the. mean number of evaporated neutrons is 3.7 times the mean number of neutrons evaporated from copper, while the mean number of evaporated protons. is only 1.6 times that for copper. The ratio of the mean 0 10 20 30 40 Ao4 o (J1 , Zi)=exp[PA-Q-R(Zi-SAi)2J, where the values of the parameters, according to our data, are P = 0.11, Q = 12.8, R= 1.2, S = 0.433. Fig. 2. Curve 1 is the relation between the cumula- tive isobar yield and the number of emitted nucleons, and Curve 2 is the theoretical relation calculated for A = 200 and Ep = 400 Mev [5]. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 number of evaporated neutrons to the mean number of evaporated protons for hafnium is almost three times as great as that for copper. These data are evidence of the sharp increase in the number of eva- porated neutrons with the atomic number of the irradiated nuclei (from 29 to 72), while the number of cascade neutrons remains constant (2 for copper and 2.5 for hafnium). After the data were obtained, the mean excitation energy of the hafnium nucleus was determined. It turned out to be 150 Mev, which is in agreement with the calculated values in [7]. 1. A. A. Pozdnyakov, Zhur. Anal. Khim. 2, 566 (1956). 2. A. P. Vinogradov, I. P. Alimarin, V. I. Baranov, A. K. Lavrukhina et al., Session of the Academy of Sciences, USSR on the Peaceful Uses of Atomic Energy (Meeting of the Division of Chemical Sciences) [in Russian] (Izd. AN SSSR, 1955) p.97. 3. T. V. Malysheva and I. P. Alimarin, Zhur. Eksp. i Teor. Fiz. 35, 1103 (1958). A. K. Lavrukhina, L. D. Krasavina, F. I. Pavlots- laya, and I. M. Grechishcheva, Atomnaya Energiya 2, 345 (1957). ? 5. I. Jackson, Canad. J. Phys. 35, 21 (1957). 6. S. Rudstam, Phil. Mag. 44, 1131 (1953). 7. N. Metropolis, R. Bivis et al., Phys. Rev. 101, 204 (1958). * Original Russian pagination. See C. B. translation. AN AUTORADIOGRAPHIC METHOD OF INVESTIGATING INK AND PENCIL LINES ON DOCUMENTS B. E. Gordon and V. K. Lisichenko Translated from Atomnaya Energiya,Vol. 7, No. 4, pp. 384-385 October, 1959 Original article submitted April 23, 1959 The ascertainment of additions and corrections on documents, made at a later date after the original text was written, is of great importance in criminological practice. It has been proposed that the relative remoteness of the date on which alterations were made in texts written with a ferric gallate ink, which con- tains large amounts of ferrous chloride or ferrous sulfate, be determined with respect to the migration of chlorine or sulfate ions from the written lines into the paper. However, the usual chemical analysis of chloride line traces yields satisfactory results only for a con- siderable concentration of chlorine ions in the ink, and, therefore, we replaced this method by autoradio- graphic detection. The part under investigation of the document in question was soaked in a 0.1 N solution of AgNO3, which was labeled with Agu? with an activity of mC ml, or in a 0.1 N solution of HNO3 or a solution of monovalent thallium sulfate, which were labeled with Tl . After 5 min, the document was rinsed five times in a 0.0116 solution of HNO3 in order to remove the excess reagent. After drying, the document was placed in contact with photographic paper in dark- ness. After one day, the obtained radiogram was deve- loped and fixed in the usual manner. In investigating lines made with aniline ink, which contans a negligible amount of chlorides, it appeared that the migration of chlorine ions could not be detec- ted. However, it was established that, due to the adsorption of the radioactive reagent by the ink dye, the radiographic image of the ink line was obtained. Such an image is obtained also if an ink made of a chemically pure methyl violet dye, where extraneous chlorine ions are almost completely absent, is used. The image does not become blurred after the document Fig. 1. Autoradiogram of a text consisting of figures, which was written with a methyl violet ink, after treatment with an AgNO3 so- lution which was labeled with Aguo The original text was written a year and a half ago; a month before the investigation, the numbers 5 and 6 were added with the same ink. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 is kept in air saturated with water vapor, and its size almost exactly corresponds to that of the ink lines. It appeared that the adsorbability of silver by ink lines depends on whether the text was written a long time ago. As can be seen from the photograph (Fig. 1), the lines made recently on the paper yield more intensive radiographic prints than the lines which were made a long time ago. In contrast to acid dyes, the basic ink dyes adsorb also radioactive isotopes which enter the composition of certain anions. However, in this, the remoteness of the date on which the text was written is not manifested. Thus, even in treating faded texts with solutions of Na2S, NaI, or K4Fe(CN)6, which are labeled with Ste, I1, and CA, respectively, clear radiographic prints are obtained. Especially good prints of texts written with violet and blue inks were obtained by adsorption of complex Fe(CN)s- , Zn(CNS)4-, T1Br4, and CdI4 anions. The last three anions are readily formed when ZnSO4, T12 (SO4), and CdSO4 are dissolved in excess amounts of KCNS. KBr, and NaI, respectively. Any atom of a complex anion can be labeled with a suitable radio-. active isotope. According to the Fajans - Panet rule, anions which form least soluble compounds with the dye' are adsorbed best, and, consequently, they provide more contrasting radiographic prints. This provides the possibility of differentiating inks and of detecting additions in the text. For instance, lines written with a blue ink, based on the "Ts" methylene blue dye, adsorb ferro-cyanide ions more intensively than lines containing the ordinary methylene blue dye. This. can be clearly seen on the autoradiograph (Fig. 2). The paper of documents also adsorbs radioactive isotopes, especially if they enter the composition of cations. Third-class writing paper adsorbs radioactive isotopes to a lesser extent than the first- and second- A B Fig. 2. A) Photograph of a text consisting of figures. The two middle figures in both lines are written with methylene blue ink, and the end figures are written with the "Ts" methylene blue . B) Autoradiograph of the same text after treatment with a solution of K4Fe(CN)6 which is labeled with CiA. class writing papers. Coated paper with large amounts of fillers adsorbs silver ions so strongly that ink lines can be hardly distinguished from the general radiogram background. Lines made with graphite, graphite tracing,. and colored pencils also adsorb radioactive isotopes. The adsorption by pencil lines containing basic dyes is determined by the latter. However, the dependence on time is not observed in all cases. Acid dyes which enter the composition of pencil lines (for instance, eosin) actually adsorb only cations. Soft-graphite pencils, which contain more graphite and carbon black than hard pencils, adsorb cations better than the latter. Printing dyes adsorb also silver and thallium cations. Thus, in a number of cases, by means of_the described method and by using radioactive isotopes, more contrasting photostats of faded originals can be prepared, and additions written with different writing materials or written at different times can be detected. REFLECTION OF NEUTRONS WITH. DIFFERENT ENERGIES FROM PARAFFIN AND WATER A. M. Kogan, G. G. Petrov, L. A. Chudov, and P. A. Yampol'skii Translated from Atomnaya Energiya, Vol. 7, No. 4, pp. 385-386 October, 1959 Original article submitted April 2, 1959 In solving problems in connection with the bio- neutrons with different energies from tissue and the logical action of neutrons, it is very important to dependence of the reflection coefficient on the beam know the quantity characterizing the reflection of geometry. In connection with this, we measured the Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 magnitude and the angular dependence of neutron reflection from tissue-equivalent substances in a wide- energy interval. In experiments, we determined the ratio of the reflux of neutrons of all energies from a medium to the incident flux of the neutrons under. investigation. Our aim was to find the portion of the over-all number of incident neutrons which was absorbed in the substances. Two methods of reflection measurement were used. The first method was used in those cases where the neutron source had small dimensions so that it could be considered almost as a point source. The second method was used in measuring the albedo of slow neutrons in neutron beams extracted from the channel of a nuclear reactor. The first method consisted in the following. By means of manganese foils, the radial distribution of the absorption density was measured in a large water tank, at the center of which the source was placed. The integration of the activity of foils throughout the entire tank volume made it possible to determine the source strength in relative units which were related to the activity of a standard foil. If, after this, the source was placed at a sufficiently great distance from the boundary of the material under investigation, the incident flux at the boundary could be considered as a plane flux. Then, for reasons of symmetry, it was considered that the activity integral of standard foils throughout the depth of the material reflected the number of neutrons which were absorbed, i.e., the number of neutrons which did not leave the surface. At the same time, the number of incident neutrons was determined with respect to the source strength and the distance between the source and the.surface. If the source strength in water was determined,and the reflection from paraffin was measured, a correc- tion, connected with different macroscopic absorption cross sections of paraffin and water, was introduced in the result. A water tank 110 cm in diameter and 130 cm high and a rectangular paraffin block in the shape of a parallelpiped with dimensions equal to 40 X 40 X 60 cm were used in the experiments. The distance from the source to the surface was 50-150 cm. By this method, we measured the paraffin reflection of neutrons from a polonium-beryllium source (average energy: 5 Mev) and the reflection of photoneut7ons from sodium-beryllium (0.83 Mev), sodium-deuterium (0.22 Mev), and antimony-beryl- lium (25 kev) sources. In measurements in a reactor, the second method was used. For a relative determination of the incident flux, the collimated neutron beam from the nuclear reactor reflector was introduced into a device which, for the neutrons, acted as an absolute black body. This device was made in the shape of a thin-walled tube, which ended with a hollow sphere that was surrounded TABLE 1. Neutron Reflection Coefficient for Normal Incidence Neutron Paraffin Neutron Water energy reflection energy reflection coefficient coefficient 5 Mev 0.06 2.7 kev 0.47 0.83 Mev 0.12 130 ev 0.56 0.22 Mev 0.19 5 ev 0.71 25 kev 0.38 Thermal 0.58 TABLE 2. Dependence of the Reflection Coefficient on the Angle of Neutron Incidence Angle of incidence Neutron energy 0? 1 15? I 30? I 45? 60? I 75? 5 Mev 0,06 0,110 0,21 0,32 0,50 0,74 0,22 Mev 0,19 - - 0,44 0,61 - 5 ev 0,71 - 0,74 - 0,80 - Thermal 0,58 - 0,63 - 0,76 - with a thick layer of a weak water solution of man- ganous chloride. The sphere diameter was 24 cm and the tube diameter was 3.5 cm. Thus, the neutron beam was not reflected back after it reached the inside of the sphere, but was entirely absorbed. The total solution activity characterized the magnitude of the incident neutron flux. The following filters were used for separating neutrons of different energies: a cadmium filter with a thickness of 1 mm (which absorbed thermal neutrons) and a boron 0.4 g/ cm2 thick. filter (which absorbed, beside thermal neutrons, also neutrons with an energy of several electron volts). For a combination of a boron filter with a cobalt layer, also neutrons with an energy of - 130 ev were knocked out of the beam; this was due to resonance scattering. In a similar manner, the sodium filter extracted neutrons with an energy of " 2.7 kev from the beam. The sodium and the cobalt filters were placed in such a manner that the neutrons scattered by these filters did not fall into the sphere. After the incident flux was measured, the reflection of neutrons from the water surface was determined. For this, a calibrated neutron beam was directed toward a thin- walled aluminum tank, which was filled with a solution of manganous chloride. The number of non- reflected neutrons was determined with respect to the activity of the solution in the tank. The effect of neutrons with different energies was determined by fractionating the beam by means of filters. The activity of solutions was determined with respect to standard metallic manganese specimens, Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 which were deposited electrolytically. The irradiation of the rectangular tank at different fixed angles 0 between the beam and the normal to the surface provided data on the angular dependence of the neutron reflection coefficient. The results of all measurements are shown in Tables 1 and 2. In considering these data, it shduld be first noted that the coefficient of neutron reflection from a hydrogenous substance decreases with an increase in energy, and that an increase in albedo is observed only in passing from thermal energies to energies of several electron volts. Such a character of the relation between the albedo and the energy of neutrons is in agreement with data from [1]. The dependence of the albedo on the incidence angle 0 for all investigated energy values can be expressed by the relation (1-(x)0 = (1-a)0_0 cosO. The reflection coefficient equal to 0.58, which was obtained for the normal incidence of thermal neutrons, is considerably smaller than the albedo of neutrons for paraffin, whose magnitude, equal to 0.83, is ordinarily used in literature. This albedo value for an isotropic distribution of incident neutrons was obtained earlier in [2]. If the albedo for an isotropic distribution is calculated by using the obtained angular dependence of the albedo and the .albedo magnitude for the normal neutron incidence, it will be equal to 0.73, which is considerably closer to the value of 0.83. The authors extend their thanks to the graduate of the Leningrad Polytechnical Institute, G. P. Gordeev, who collaborated in measuring the albedo of slow neutrons. LITERATURE CITED 1. L. Cave, Brit. J. Radiol. 27, 273 (1954). 2.1 E. Amaldi and E. Fermi, Phys. Rev. 50, 899 (1936). DISTRIBUTION OF THE ABSORPTION DENSITY OF NEUTRONS IN PARAFFIN A. M. Kogan, G. G. Petrov, L. A. Chudov, and P. A. Yampol'skii Translated from Atomnaya Energiya, Vol. 7, No. 4, pp. 386-388 October, 1959 Original article submitted April 2, 1959 The neutron tissue dose is partially determined by the energy which is liberated inside the tissue in the capture of neutrons. In dependence on the initial neutron energy, this portion of the tissue dose will constitute different contributions to the over all dose. For instance, for neutrons with an initial energy of several kiloelectron volts, the tissue dose will almost entirely be determined by energy which is released in capture. For neutrons with an initial energy of 1 Mev, a substantial part of the dose will be determined by energy which is dissipated by neutrons in the slowdown process. In order to determine the capture component of a neutron dose, we investigated the spatial distri- bution of neutron absorption in paraffin, which simula- ted the biological tissue. These measurements were performed for a normal incidence of an extensive neutron beam on a flat paraffin surface. The paraffin block was in the shape of a rectangular parallelpiped with dimensions equal to 40 X 40 X 60 cm. The neutrons were aimed at the 40 X 40 cm face. The length of 60 cm. was. chosen for the purpose of making the neutron density approach zero at a sufficiently great distance from the back face of the paraffin block, so that the neutrons were completely absorbed in the block for any initial neutron energies used in experiments. In order to obtain data for determining the transverse block dimensions, we performed measure- ments of neutron density in paraffin (along the block axis) for different transverse dimensions of the block. For small block dimensions, the neutron density at the axis depended on its transverse dimensions; how- ever, when certain critical dimensions were attained, a further increase in the block size did not influence the magnitude of neutron density. The critical block dimensions, depending on the initial neutron energy for an energy of 5 Mev, were less than 40 cm. Thus, the absorption of neutrons in a block of the indicated size coincided with the absorption in semiinfinite space filled with paraffin. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 1,0 0,9 0,8 07 0 6 a , ; c 0, 5 ?a OP 4 02 8 10 i2 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Depth, cm Density distribution of the absorption of neutrons with different energies in paraffin. Neutron energies: ) thermal neutrons; - - - ) 5 ev;-- -?- 25 kev;-?--??- 220 kev;-???- 0.83 Mev; -A-) 2.9 Mev; -x-) 5 Mev. The measurement of neutron density was per- formed by means of thin manganese foils. In experiments, the depth distribution of the absorption density of incident neutrons with the follow- ing energies was determined: 1. thermal neutrons which were obtained by fil- tering a beam extracted from the channel of a nuclear reactor through cadmium (thickness: 1mm); 2. neutrons with an energy of - 5 ev, which were separated from a beam of resonance neutrons from a nuclear reactor by combining a boron (0.6 g/ cm2) and a cadmium (1 mm) filter; 3. photoneutrons from an antimony-beryllium source with an energy of 25 kev; 4. photoneutrons from a sodium-deuterium source with an energy of 220 kev; 5. photoneutrons from a sodium-beryllium source with an energy of 0.83 Mev; 6. neutrons produced by the Hi (d, n)He2 reaction with an energy of 2.9 Mev (the deuteron energy was 1.8 Mev, and the emergence angle of neutrons in the laboratory coordinate system was 90?); 7. neutrons from a polonium-beryllium source with an average energy of 5 Mev.* The maximum statistical error in measuring the activity of foils was ^? 3116. The measurement results are shown in the figure. All the curves are characterized by the presence of a maximum, which is shifted toward the depth of paraffin as the energy increases. In passing from thermal neutrons to neutrons with an energy of several electron volts, a drastic shift of the maximum from 0.5 to 2.5 cm is observed. This is perhaps connected with the fact that the maximum absorption probably takes place at a depth which is of the order of the transport path length of an incident neutron, and since the scattering cross section of neutrons in paraffin decreases approxi- mately fourfold for a neutron energy exceeding the energy of the proton bond in a paraffin molecule, the free neutron path correspondingly increases. The com- paratively slow shift of the maximum toward the depth as the energy increases to 5 Mev can also be explained by a weak dependence of the scattering cross section in this energy interval. It is obvious from the figure that the ratio of absorption at the maximum to absorption at the surface tends to increase, which can to a certain extent characterize the relative amount of slow neutrons leaving'the front paraffin surface, i.e., it can charac- terize the reflection coefficient. The rate of the drop in absorption density beyond the maximum decreases. as the energy of incident neutrons increases; this is to be expected, as the length of the free neutron path increases. The departure from this regularity at greater depths in the case of neutrons with an energy of ^' 5 ev was obviously connected with the fact that, in the boron filter which separated these neutrons, a small amount of faster neutrons was separated from the beam; this was also due to the inaccuracy in measuring the activity by-means of cadmium and cadmium-boron filters. The difference between these measurements determined the values given in the figure. ? J. Elitot, W. McGarry, W. Faust. Phys. Rev. 93, 1348 (1954). Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 News of Science and Technology INTERNATIONAL CONFERENCE ON COSMIC RAYS V. Parkhit'ko The International Conference on Cosmic Rays, convened under the auspices of the International Union of Pure and Applied Physics, met June 6-11, 1959, in the auditorium of the M. V. Lomonosov Moscow State University. The Conference was attended by representatives of scientific organizations from 25 nations. The widespread interest in this Conference is to be explained by the particular significance attached to problems of cosmic rays in physics today. Cosmic- ray particles of exceptional high energy are a power- ful tool in the study of the atomic nucleus, and also provide information to science on the spectacular events taking place in the Universe which give birth to these remarkable rays. A new landmark in this field of research, as emphasized in the introductory remarks by Academician D. V. Skobel'tsyn, has been established by the launching of the first artificial satellites of the earth and sun, an achievement of historical import. A completely novel approach to research on the Cosmos has been inaugurated, and new phenomena of exceptional interest have been reported. The exchange of views on the essence of those scientific achievements constitutes a significant contribution to cosmic-ray research. The most prominent problem in the field of cosmic- ray studies is the unraveling of the nature of nuclear interactions at critically high energies beyond the reach of present-day accelerators. A session of the Con- ference,chaired by Britain's leading scientist, C. F. Powell, an honorary member of the Academy of Sci- ences of the USSR, was devoted to the achievements of world science in this area. The first report was delivered by Prof. M. Schein (USA). He gave an account of research on nuclear interactions at energies in excess of 1012 ev, Photoemulsion tracking techniques showed great promise in studies of high-energy particles. Prof. D. H. Perkins reported on research using this technique, carried out at an altitude of 10,000 meters on board a jet plane. Experiments employing photoemulsion techniques resulted in the discovery of new cosmic- ray processes, and involved thousands of flying hours. The data reported stimulated a lively discussion at the Conference. The Soviet scientist N. L. Grigorov reported a novel technique facilitating research for cosmic- particle energies. Interest was also heightened by announcements of work conducted at Pamir under the supervision of Prof. N. A. Dobrotin. The pattern of interaction between nucleons and nuclei was studied at heights in the mountains. The particle energy was successfully measured by Grigorov's method. Valuable data on high-energy interactions were also reported in papers by physicists of the Kazakh SSR and in experiments of Hungarian and Japanese scientists. The second session of the Conference discussed one of the fundamental problems in modern physics, that of the interaction of elementary particles with atomic nuclei at energies thousands and millions of times in excess of anything achieved in the largest accelerators now in existence. A review report delivered by Prof. E. L. Feinberg (USSR) was followed by reports on new research efforts in that field of study. Soviet and foreign scientists expounded their views on the essentials of the process of multiple production of particles. The basic fact is that each collision between particles at exceptionally high energies results in the production of a large number of new fragment particles. Seven experiments on this topic performed in Japan were described at the Conference by Japanese scientists S. Hayakawa and J. Nishimura. The Soviet physicist D. S. Chernavskii told of research carried out at the P. N. Lebedev Institute of Physics in Moscow. The following days at the Conference were used for discussion of the results of investigations of broad atmospheric showers. A special session dealt with studies of primary cosmic radiation. The outstanding feature of this primary radiation is that during its travel it gives rise to a host of "descendants," the secondary particles. Some of these "descendants' possess great penetrating power. Mu-mesons, for example, are known to penetrate a thousand meters deep into the earth. The session of July 10 was extremely interesting. Results of research on primary cosmic radiation by means of airborne balloons, rockets, and satellites were discussed. Special attention was focused on the problem of the origin of the cloud of charged particles enveloping the earth. Prior to the launching of earth satellites, no one had suspected the existence of such a cloud. The phenomenon was subjected to painstaking investigation with instruments carried on board the third Soviet earth satellite. The first Soviet cosmic rocket later passed right through that cloud and beyond it, measuring the composition of the radiation in detail. Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP1O-02196ROO0100040003-7 Photo taken in the Conference auditorium. Seated,from left to right: Prof. B. Rossi (USA), Academician D. V. Skobel'tsyn (USSR), and Prof. C. F. Powell (Britain) (photo by the author ). At the present conjuncture, ample experimental material has been accumulated on the origin of the two cloud belts (inner and outer belts), a report on which was made at the Conference.. The inner belt passes above the equator at a height of several thousand kilometers, and is made up of high-energy protons. The outer belt extends to a distance of the order of about 50,000 km from the earth, and is made up of relatively low-energy electrons. Prof. J. Van Allen, who was the first to discover the radiation belts, deli- vered a report on American research in that area. Soviet research on the same topic was summed up in a report by Corresponding Member of the Academy of Sciences,of the USSR S. M. Vernov, and Candidate in Physical and Mathematical Sciences A. E. Chudakov. Soviet and American researchers have reached the conclusion that the charged particles found in the inner cloud belt are formed as a result of decay of neutrons emitted by the earth's atmosphere as cosmic rays impinge on the atmosphere. Particles in the outer cloud belt may possibly be of solar origin, in the view of some scientists. A report delivered by Soviet scientists N. V. Pushkov and S. F. Dolginov stating that electric currents which appreciably alter the geomagnetic field flow in the charged-particle clouds made a deep impression. This phenomenon was detected by. means of a mag- netograph mounted on board the first Soviet space rocket (Lunik). Interest was stimulated by a paper delivered by Australian scientists, telling of observations of Soviet artificial earth satellites by Australian observation teams. The closing day of the Conference, devoted to the problem of the origin of cosmic rays, had as its most interesting papers reports by Soviet scientist V. L. Ginzberg, "Some problems concerning the theory of the origin of cosmic rays," L. Davis (USA), "On diffu- sion of cosmic rays throughout the Galaxy," and S. Ha- yakawa, M. Koshiba, and N. Hiroshima (Japan), "The acceleration mechanism of cosmic-ray particles." Speaking in the name of foreign guests at the close of the Conference, Prof. B. Rossi, chairman of the Cosmic-Rays Commission of the International Union of Pure and Applied Physics, addressed the gathering. He thanked the Soviet scientists for their hospitality, and remarked on the favorable conditions provided to expedite the work of the Conference. Declassified and Approved For Release 2013/02/21 : CIA-RDP1O-02196ROO0100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 NINTH INTERNATIONAL CONFERENCE ON HIGH- ENERGY PHYSICS B. Govorkov The Ninth International Conference on'High- Energy Physics. met in Kiev, July 15-25, 1959. Over 300 scientists of prominence from 32 nations were in attendance at the Conference, with delegates from the largest international research institutions, e.g., the Joint Institute for Nuclear Studies (Dubna), the Center of European Nuclear Research (CERN), and including Prof. A. I. Alikhanov, D. I. Blokhintsev, N. N. Bogo= lyubov, V. I. Veksler, L. D. Landau, B. M. Pontecorvo, I. E. Tamm (all from the USSR), L. Alvarez, V. Weiss- kopf, E. McMillan, W. Panofsky, E. Segre, G. F. Chew, L. Schiff, J. Steinberger (USA), R. Peierls, A. Salam (Britain), Wang Hang-chang (China), H. Yukawa (Japan), E. Amaldi (Italy), and G.Bernadini, R. Hof- stadter (CERN). A system of review papers was adopted at the Conference. Leading specialists in the fundamental branches of high-energy particle physics appeared with participants in the panel sessions-, and discussed the review reports to be delivered in the plenary sessions. The first plenary session, held on July 20, was opened by the chairman of the organizing committee for the conference, D. I. Blokhintsev. The participants remained standing in silence to honor the memory of the distinguished physicists Frederic Joliot-Curie, Ernest Lawrence, and Wolfgang Pauli, all of whom passed away during the interim between the Eigth and Ninth conferences. Prof. G. Bernadini delivered a review report on photoproduction of pions and the Compton effect on a proton. He analyzed in detail some new data reported during the previous year in several American laboratories, relating to the nature of the maxima 2 and 3 detected in the photoproduction cross sections of the mesons. Despite the fact that with the commissioning of the - 1 Bev synchrotrons (in USA, Italy), the interests of physicists have shifted to the higher-energy region (^600 Mev to 1 Bev), there are. still a host of classi- cal effects in meson physics observable in the region close to the photoproduction threshold for mesons which require measurement and refinement, these being: measuring the threshold photoproduction cross sections of pions, interaction constants, applicability of theoretical descriptions of threshold phenomena based primarily on the Chew-Low model or on dis- persion relations. The most complete experimental results relating to this energy region are those reported by Soviet physicists working with the' synchrotron of the Institute of Physics of the Academy of Sciences of the USSR. Questions pertaining to nucleon scattering of nucleons and single production of pions in lr- n- and n -n -interactions, intimately associated with the photoproduction of pions, were dealt with in a report by Prof. B. M. Pontecorvo. An analysis of the experi- Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 ments carried out on the accelerators available at the Dubna, and Chicago laboratories, and other institutions, for the purpose of verifying the principle of charge invariance in processes involving participation of pions and nucleons, failed to show a single reliable case of violation of that principle; the promising method pursued to verify the principle was the study of an interaction, forbidden with respect to isotopic spin, between two deuterons, resulting in the formation of a neutral it -meson and a helium nucleus. It was noted in the report that, as a result of completion of experi- ments on 7r- p-scattering at 400 Mev (USSR, USA), much knowledge has been gained on the phase shifts of 7r=p-scattering. More accurate measurements of the total cross sections for ?r-p--interactions at 1 Bev energy have fully confirmed R. Wilson's hypothesis, which held that two maxima must exist (corresponding to photoproduction of mesons) in the energy dependence of total 7r =p-scattering. These maxima have been found, and there are now three resonance peaks in the total cross section of the 7r -p-interactions: the first at - 190 Mev, due to a strong interaction between. the state T = 3/ 2 and I = 3/ 2 (positive parity ); the second at ' 650 Mev, a strong interaction between states T = 1/ 2 and I = 3/ 2 (negative parity); the nature of the third maximum, at 950 Mev energy, is more obscure, but apparently marks a state having I=5/2. .It is to be noted that many new ."discoveries" were reported at the Conference. Experiments per- formed in the USSR (at Dubna) and in Great Britain invalidated the hypothesis of the existence of an isotopic scalar Irv -meson having a mass close to that of the conventional 7r0-meson. This hypothesis had been advanced to account for several contradic- tions in the field of low-energy meson physics. New data on it -p-scattering showed that no serious discrepancies exist between experimental Tr-p -scatter- ing data and dispersion relations (known as the Puppi- Sta-helin problem). A lively discussion and considerable interest centered around data on the pair production of pions from meson-nucleon collisions studied in the USSR (Dubna),.Italy, and USA (Berkeley), opening up new avenues of research into the nature of the it -ir - inter- action. B. M. Pontecorvo reported, in a number of significant successes achieved in experimental tech- nique, the development of a gaseous Cerenkov counter with an index of refraction continuously variable from 1.00 to 1.23 (MIT, United States), and a hodoscopic system with pulsed power supplies for polarization experiments (Joint Institute, Dubna). The most interesting data obtained on the world's two largest proton synchrotrons, at Dubna and Berkeley, were reviewed in reports delivered by Prof. E. Segre and Academician V. I. Veksler. Segre reported something rather new in experi- mental technique: the production of enriched beams of antiprotons (as much as one antiproton per accele- rator pulse), by means of absorbers and magnets, and especially by means of electrostatic separators. Ex- periments using photoemulsions (in Italy and the USA) have resulted in corrected values for the mass ratio of the antiproton to the proton. This, mass ratio is equal to unity to an.accuracy of t 116. The report reviewed new data on measurements of interaction cross sections (elastic scattering and annihilation cross sections) of antiprotons with hydrogen, deuterium, and carbon. Segre greeted the physicists of the Joint Institute, where a team has produced an anti- proton beam with a 2.8 Bev/ c pulse, and has begun research work in this intriguing realm of physics. The Chinese scientist Prof. Wang Hang-chang (working currently at the Dubna Joint Institute) took the floor in the discussion of Segre's presentation, to demonstrate two interesting plates obtained in work with a propane bubble chamber. These plates, showed, for the first time, strikingly clear cases of antiproton generation. One of the most interesting reports was made by Academician V. I. Veksler, and provided, for, the first time, a systematic analysis of nucleon-nucleon and pion-nucleon interactions at energies ranging from 1.5-2 to Bev. Examination of the results of highly precise measurements of elastic p-p-scattering at 8.5 Bev (Dubna) and 3 Bev (Berkeley) demonstrated the existence of what is termed potential scattering, i.e., leads to the conclusion that the scattering amplitude at high energies is not a purely imaginary quantity, as would follow from the optical theorem. These results were made possible by a new research tech- nique, in which photographic plates are placed at right angles to the accelerator beam (a practice ini- tiated at Dubna), allowing a shift of as much as 0.2? in the laboratory system or coordinates. An analysis of experiments on inelastic zr-ir- and 7r -n-interactions carried out at energies of 2.6 and 9 Bev by the Berkeley and Dubna groups shows an important discrepancy between the empirical data and predicted statistical theory, and leads to an understanding of the existence and prominent role of peripheral encounters. With the aid of an idea advanced by Academician I. E. Tamm, these encoun- ters are associated to concepts of single-meson ex- change where one or two isobars appear as a result. The essentially new approach contained in Tamm's suggestion is that by making the assumption of single-meson exchange, it becomes possible to obtain completely specified quantitative relationships bet- ween the probabilities of different isotopic channels of the reactions. Experimental results from peripheral Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP1O-02196ROO0100040003-7 collisions studied by the Dubna team show excell ent agreement with Tamm's predictions. An examination of empirical data on 7r -p-interactions reported by the Dubna and Berkeley teams shows the totality of the available experimental results to be at variance with predictions of statistical theory for both low (^" 1.5 Bev) and high energies. The only model which is evidently not at odds with the totality of all facts reported on 7r -p- interactions in that energy range is the model according to which a high-energy pion interacting with a proton results in a 6 -meson knocked out of the mesonic shell of the nucleon. As demonstrated by a phase analysis of elastic 7r -p-scattering, the mechanism underlying scattering of this type at high energies ( > 2 Bev) is essentially different from the elastic p-p-scattering mechanism. For 7r -p-scattering as an example, spin interactions are negligible, while.the scattering amplitude is a purely imaginary quantity. A typical feature of 7r-p- and p-p-scattering at high energies (2-10 Bev) is the fact that the effective collision parameter determining the magnitude of the interaction cross section is energy- independent over a broad range of energies. In Veksler's view, it would be important to tie up this quantity with meson theory. Questions related to investigations of the structure of nucleons and checking the validity of quantum electrodynamics at small distances were taken up in re- ports by Profs. F. Hofstadter, W. Panofsky, and L. Schiff. Hofstadter's report dealt with the results of experi- ments on studies of proton and neutron structures, performed by the reporter and his associates on the linear accelerator at Stanford (USA). The basic prob- lem encountered in studies of proton structure is the determination of the phenomenological form-factors Flp (q2) and F2p (q2), the first of which takes the charge distribution of the Dirac magnetic moment into account, while the second accounts for the distri- bution of the anomalous magnetic moment. Both form factors are independent functions of the pulse aq transmitted in the event of a collision between an electron and a proton. An analysis of the experimen- tal data, adduced in the report, shows that Flp = F2p within the limits of accuracy attainable (- 1516), and that they are actually dependent on q alone. New data from neutron studies at Stanford, based on the method of direct determination of the difference between the cross sections of quasielastic scattering of electrons on deuterons and elastic scattering of electrons on protons, were discussd in detail in this paper. The results showed agreement with the fact that F In= 0, F2n = F1p = F2p, where if we use some model for the exponential distribution of charge density and magnetic dipole moment in interpreting the results, we get in = 0.8 ' 10-14cm. V. Panofsky's report was most interesting for the experiments proposed for verifying the validity of quantum electrodynamics at short range. The necessity for such verification arises from the fact that in inter- preting experimental data on nucleon scattering of electrons, we must presently assume that quantum elec- trodynamics remains valid for all values of the momen- tum transferred in the collision. One of the proposed experiments is in the prepa- ratory stage at Stanford University, and involves scattering of electrons on electrons, based on the use of the method of head-on collisions of electron beams emergent from two separate annular storage paths. A precision of - 3 To which is fully attainable in this experiment makes it possible to approximate to the elemental length 3 ? 10-15 cm. R. Wilson (USA) took the floor in the discussion to tell of an experiment now in preparation aimed at probing the structure of the neutron, and based on a technique of recording coin- cidences of recoil electrons and neutrons scattered on deuterons. Some theoretical problems underlying strong interactions of common particles were discussed in papers presented by Prof. G. F. Chew (USA) and Prof. Ya. A. Smorodinskii (USSR). Smorodinskii's paper gave a phenomological analysis of experiments on nucleon scattering of nucleons (N - N) carried out on synchrocyclotrons at Berkeley, Rochester, Cambridge (USA), Dubna (USSR), Liverpool, and Harwell (Great Britain). These experiments are geared to a program with the pace set predominantly by Soviet physicists. Pointing out the fact that presently available data are inadequate for a complete analysis of N - N -scatter- ing, the reporter sketched a program of further ex- perimental research work in clear outline. The report emphasized the fact that the total available data on N - N - scattering could not be described by a poten- tial dependent solely on the coordinates and spins, so that the potential must include the relation between spin and orbital motion. It is therefore natural that the results presented by Soviet theoreticians A. F. Grashin and I. Yu. Kobzarev, who computed the spin- orbital interaction potential from approximate disper- sion relations, stimulated much discussion. Chews report dealt with a new approach to the problem of strong interactions between ordinary particles, based on the binary dispersion concepts advanced by Mandel'shtam. According to that con- cept, all three reactions, N - N -, 7r-N? 7r-7r -inter- tions, may be described by means of a single analytic function,. while the behavior of the analytic function over a small region of the complex plane is deter- mined principally by the closest singularities, accord-ing to the assumption of Mandel'shtam and Chew. The problem reduces to finding the functions having Declassified and Approved For Release 2013/02/21 : CIA-RDP1O-02196ROO0100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP1O-02196ROO0100040003-7 the required singularities, which in turn calls for a solution of complex nonlinear integral equations. The solution of this problem must be reduced to the fact that the amplitudes of the processes will be expressed in such parameters as interaction constants and masses. The hope remains that the mathematical tools developed will make possible a description of nuclear forces as far as to the core of the nucleus, and right up to an energy of 1 Bev for 7r -N- and n -7r scattering reactions. The discussion on Chew's paper was devoted in the main to questions concerning the possibility of measuring it -ir -interactions, with Prof. D. I. Blokhintsev, V. N. Gribov (USSR), Prof. E. L. Lomon (Canada), and others taking the floor on that point. Questions related to the production of strange particles and their interactions were discussed in the plenary session chaired by Prof. Wang Hang-chang, and in reports presented by Professors J. Steinberger, L. Alvarez, and A. Salam. Steinberger's report, devoted to the formation of strange particles, had as its high point of interest the data accumulated by a team under Prof. Alvarez, from hydrogen bubble chamber observations of events involving the formation of a neutral cascade hyperon in an interaction between a K--meson and a proton, of the type K--gyp--->5?+K? Measurements demonstrated that the neutral cascade hyperon decayed according to the decay scheme E?->A?+n? , and had a mass,1326 f 20 Mev, which fits well with the mass found for the negative cascade hyperon, 1321 35 Mev. The report delivered by Prof. Alvarez was based to a considerable extent on papers treating K-meson interaction experiments performed by his group with the aid of liquid-hydrogen and deuterium bubble chambers. In addition, the results of interactions between K+ -mesons and nucleons, as well as data on hyperon-nucleon interactions were dealt with. The report furnished information on an increase in the number of decay events involving A? -particles formed in the K- + D -> A? + ir- + p reaction. This increase showed that the apparent asymmetry observed about a year ago in A? -decay is in reality a statistical fluctuation, and that there are consequently no reasons for assuming that parity is not conserved in strong interactions in which strange particles take part. In the discussion ensuing after presentation of the papers on strange particles, the greatest interest was evoked by statements made by Ting Ta-tsao, Prof. Wang Hang-chang (Joint Institute), and M. Stevenson (USA). Ting Ta-tsao took the floor to report some results obtained by a team of research scientists at the Joint Institute for Nuclear Studies bearing on the production of strange particles in interactions between 8.6 Bev it--mesons and protons. Wang Hang-chang demonstrated an interesting slide of a plate taken in a bubble chamber; analysis of the plate shows that we are dealing here with what seems to be a new particle of mass 742 t 218 Mev, which disintegrates into a 7r+-meson and a K? -meson. Stevenson demonstrated a plate obtained by the Alvarez group where we see for the first time the production of the A + A pair in an antiproton-proton collision event. Since the method of dispersion relations is the principal theoretical research method used in studies of interactions between elementary particles, a separate plenary session of the Conference was devoted to an analysis of that method, with D. V. Shirkov (Dubna) and Prof. G. Lehmann (West Germany) report- ing. Shirkov's report discussed the theoretical aspects of dispersion relation studies of the usual type (based on the energy variable). Summing up the results of work carried on during the past year, the reporter noted that the year is characterized, on the one hand, by the extension of the general methods of proofs of dispersion relations to a large number of elementary-particle interaction processes and on the other hand, by the fact that the possibilities have been apparently exhausted for discrete dispersion relation processes, at least in their present form. It is therefore quite natural that much attention should be given, precisely this year, to a method for investigating the range of applicability of dispersion relations by means of an analysis of diagrams of the theory of perturbations. The basic point driven home in Lehmann's presen- tation involved problems in investigating the analytic properties of scattering amplitudes with respect to transfer of momentum and questions relating to binary dispersion concepts. These concepts apparently consti- tute a very promising and bold hypothesis, but for now it isstill only a hypothesis. It is therefore to be expected that many discussions taking place at the Conference would be devoted to various justifications for these concepts. We refer here in particular to the discussion between the reporter and Academician L. D. Landau. One of the sessions of the Conference, under the chairmanship of Academician I. E. Tamm, was devoted to new theoretical ideas advanced in the field of elementary- particle physics. Interesting reports were presented at this session by Academician L. D. Landau, Prof. M. A. Markov (USSR), Prof. W. Heisenberg (West Germany), Prof. I. Nambu (USA), Prof. W. Thirring (Switzerland), and others. Problems in strong interactions were dealt with in review reports presented by Academician A. I. Alikhanov (USSR), Prof. D. Glaser (USA), and Prof. R. Marshak (USA). Alikhanov's presentation was devoted to a consi- deration of decay of nuclei, p-mesons, and 7r-mesons. The most substantial event registered since the last conference was, as noted in the report, the elimination of the last explicit contradiction marring the universal Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196ROO0100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 theory of V - A-interaction (Gell-Mann; Feynmann, Marshak, Saunderson), by discovering IT -6- decay in the approximately correct relationship to conventional it-?-e-decay. The report provided a painstaking analysis of the accuracy of the experimental proof of the two-com- ponent neutrino theory of Salam, Landau, Lee and. Yang, invariance under time reversal in weak interac- tions, and the universality of the Fermi interaction constant, which is uniform to an accuracy of 2-31o both in the process of B -decay of nucleons,i.e., strongly interacting particles, and in the decay process of the muon. It is a well-known fact that decay of strange particles proceeds very slowly, and represents a typical weak interaction. Glaser's report was devoted to this question. A theoretical treatment of the problems of weak interactions was furnished in Marshak's report. After these presentations, a lively discussion ensued. Of particular interest were the remarks made by Prof. V. Telegdi and J. Steinberger. Telegdi gave an account of experiments investigating K-capture of a 11-meson by a nucleus of nonzero spin, and stressed the point that the spin of the p-meson could be computed directly from the experiment performed by the Dubna team (A. E. Ignatenko et al..). Steinberger, in his report, told of an experiment in which the parity of the Tr'-meson is determined directly. Experiments carried out with the aid of a liquid hydrogen chamber have confirmed the pseudoscalar nature of the it?-meson. The concluding session of the Conference was devoted to nuclear processes at exceptionally high energies. Experimental results obtained by means of cosmic-ray research were the theme of a report.. delivered by. Prof. C. F. Powell (Great Britain). These results had been discussed extensively at the International Conference on Cosmic Rays convened in Moscow in July, 1959. Theoretical questions concerning multiple production of mesons at extremely high energies were discussed in a report by Prof. E. L. Feinberg (USSR). Concluding remarks at the Conference were delivered by Academician I. E. Tamm. In the name of the International Union of Pure and Applied Physics, the chairman of the Committee on High-Energy Physics of that body, Prof. C. J. Bakker, expressed his thanks to the organizing committee for their splendid job in preparing and expediting the work of the Conference. A number of seminars were held during the Con- ference for the benefit of persons working in of the various fields of high-energy physics: a theoretical seminar, a seminar on bubble-chamber techniques, a seminar on electron accelerator experiments. In the course of these seminars, and personal encounters, those in attendance at the Conference had the oppor- tunity to discuss in detail the problems of greatest interest to them, and to share information on future research projects. The Conference was a great aid to the. cause of strengthening international collaboration between scientists. The proceedings of the Conference will be pub- lished by the USSR Academy of Sciences Press, in the form of a special collection of papers. THE SECTION ON ATOMIC SCIENCE AND ENGINEERING AT THE AMERICAN EXPOSITION IN MOSCOW The United States Exposition was open to the public from July to September, 1959, in Moscow. The atomic science section took up a very insignifi- cant amount of floor space in the exhibition, and ref- ledted superficially, and in general outline, the work of American scientists in the field of atomic energy. The sponsors of the exhibit were apparently of the opinion that a detailed account of problems touching on the use of atomic energy in the USA would be of no interest to the man-in-the-street visitor to the exhibit. This was not the case, however, as borne out by the large number of inquiries on the subject voiced by visitors. It is most unfortunate that visitors to the exhibition, including Soviet specialists on atomic energy, could not find on display any material in any way fully reflecting the achievements of American scientists in the field of atomic energy. There was only one model on display in the entire atomic section of the American exhibit, that being a model of the atomic-powered cargo and passenger vessel "Savannah." At the present time, superstructure work and finishing touches are underway with the hull of the vessel already launched, and the ship will be ready for its maiden run in the summer of 1960. This section of the exhibit reflected only three types of work in the field of atomic energy: experimental reactors, power reactors, and radioactive isotopes. Photographs showed the reactor of the Shippingport power station, the portable boiling Mater reactor of the ALPR project, the organic-moderated and organic-. Declassified and Approved For Release 2013/02/21: CIA-RDP10-02196R000100040003-7 Declassified and Approved For Release 2013/02/21 : CIA-RDP10-02196R000100040003-7 Crowd viewing a model of the atomic-powered cargo and passenger vessel "Savannah." cooled OMRE power reactor, the materials testing reactor MTR, the Brookhaven research reactor and the reactor of the Dresden power station. One could' learn from the stands and diagrams that 15 atomic- fueled power stations, delivering a total power output of 1000 Mw, are presently being planned in the USA, and that the number of reactors of all types has reached 200. A relatively large area in this'section was occupied by the radioactive isotopes and isotope applications exhibit, primarily in medicine, biology and agriculture. However, even this topic was dealt with in a very cursory and schematic fashion. Several photographs showed examples of American assistance to the Federated German Republic (West Germany) in building the research reactors at the Frankfurt and Munich Universities. ANNULAR FIXED-FIELD I STRONG-FOCUSING ACCELERATORS; The need for increased output current in cyclic accelerators has put a premium on the most rational. exploitation of the advantages of time-invariant magnetic fields in such machines. Existing cyclic accelerators of the cyclotron and synchrocyclotron types, while providing very high beam intensities, are beset by the sizable drawback that the size, weight, and cost of the facilities limit the peak proton energies attainable in the machines to < 1 Bev. The use of annular magnets of the synchrot- ron type has proved unfeasible because of the instabi- lity of the motions executed by the-particles: "Actually, in order to keep particle orbits within a narrow annular region upon acceleration, the magnetic field in,that region must'be increased 103-104 times. Recourse'to?-1 an axisymmetric field is no solution, since this runs' counter to the well known stability condition 0 < n
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