focusing (P. A. Tishkln)! a double-lens device for the study of B = coincidences (V. A. Sergienko) and a lens spectrometer intended for research on soft beta spectra (I. M. Rogachev). Spectrometer design work is being carried on under the supervision of the head of the department, Professor B. S. Dzhelepov. Research is underway at present, in the department, on neutron-deflcient isotopes of rare earth elements. This work is being performed in collaboration with the Joint Institute for Nuclear Research and the V. G. Khiopin Radium Institute of the Academy of Sciences of the USSR. Neutron-deficlent isotopes of the rare earths are pro= duced in the synchrocyclotron of the Joint Institute for Nuclear Research by bombarding a tantalum target with fast protons. They are then separated out from the target by chromatographic techniques. Research on these isotopes is of great interest for the study of the shell model of the nucleus. The research materials are reported on at annual conferences on nuclear spectroscopy, and are being published. A m o n g the experiments on neutrondeficient isotope research mention is due to the study of the rather complicated decay arrangement of He i~, and the establishment of the energy levels of Dy Is~ A theorerical research team at work in the department is taking up the study of beta spectra, conversion electrons, and the analysis of models of nuclear shells, etc.

V~ P.

AT THE TOMSK

POLYTECHNIC

INSTITUTE

Work on the design of betatron machines was initiated in 1947 at the Tomsk Polytechnic Institute, under the supervision of, and with the direct participation of A. A. Vorob'ev, M. F. FLlippov, V. N. TRoy0 B. N. Rodlmov, and A. K. Pot~zhnyi. The firstaccomplishments were the fabrtcarion of 10 Mev, 15 Mev, and P.5 M e v betatrons, and betatrons with conslderably higher parricle energies are being designed and bulk at the present time. In the course of research partially reported on earlier (I. Atomic Energys No. 3, 299, 1958)p workers at Tomsk Poly.technic introduced many new concepts in the theory and practice of this type of accelerator. L. S. Sokolov and B. A. Kononov achieved the extraction of an electron beam from a betatron doughnut by various techniques. In 1956, V. A. Moskalev proposed a variant for the design of a stereobetatron. Before long, such a betatron was in actual operation, with the active assistance of lu. M. Akimov. The stereobetatron has two accelerating chambers situated in the two=pole gaps of an electromagnet (Fig. I). Both electron beams are directed in opposition to each other, and intersect at a given point. This makes it possible, in using the betatron for flaw detection purposes, to obtain stereo shots of flaws in a workpiece, and to obtain double-field irradiation, when used in medicine applications. A special advantage of the stereobetatron is the possibility of obtaining stereo shots of processes going to completion rapidly, or of fast-movlng parts. The stereobetatron designed at Tomsk Polytechnic will be on display during 1959 at the A11-Union Industrial Exposition. One of the firstbetatrons completed without iron magnet yokes or pole pieces to be put into operation in the USSR was the one designed at Tomsk Polytechnlc (see Fig. 2), by G. I. Dimov and D. A. Noskov. In 1954, an electron synchrotron with an original design acceleraring device in the form of two ring electrodes, proposed by B. A, Solntsev, was put into operation. This novel design brought about a considerable and far-golng simpli= flcatlon of the high-frequency circuitry of the synchrotron. The betatrons designed at Tomsk Polytechnic lusRtute are used for research in nuclear physics, for training purposes, in medicine and in industrial applications. Thus, at the Cinematography Sclenliflc Research Institute, a betatron with an extracted beam is used for the quality control of photographic plates. T w o betatrons were recently shipped to the Chluese Peoples Republic. At the All-Union Industrial Exposltton held in 1958, a 25 M e v betatron constructed at Tomsk Poly~echnlc (see Fig. 3) was put on exhibit, and was awarded a first-class prize.

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Two All-Union Conferences on electron accelerators have been convened at Tomsk Polytechnic! most of the reports delivered at the two conferences were made by staff members and students of the Institute. The Physics and Engineering Department of the Institute maintains close scientific ties with many organizations in the USSR, assisting them in mastering and adjusting betatrons through consultations and supplying them with conference reports and materials.

Fig. 1. Experimental stereobetatron at 10 Mev electron energy (upper pole piece of magnet removed).

Fig. 2. Electromagnet of the 5 Mev electron energy ironless betatron. The students of the Physics and Engineering Department take an active part in the work on betatson development and research. They perform undergraduate and graduate work on the drafting Fig. 8. The 25 Mev betatron with mechanisms for and design of betatrons, carry on scientific investivertical and horizontal positioning. gations and participate in the conferences. Students receive good direct-participation and undergraduate experfenee in the laboratories of the department. The most capable and promising students from among those completing their courses in the department are retained for work in the laboratories, where everything needed for their further growth as scientists is afforded them. 1613

5) photographic recording of the observations is possible; 6) measurements are made fully automatic, .without any ldnd of controllers.

A

UF~

OBI

B

OL~

061 0~1 0 L~" u=

Fig. 2. TWO methods for recording the direction and intensity of gamma radiarion.

M~ K~

CHANGES

IN T H E

STRUCTURE

OF URANIUM

OF T H E R A W

IN C A P I T A L I S T

MATERIALS

BASE

COUNTRIES

During the first stages of the development of the production of uranium, the balk of the uranium ores were mined from occurrences of the vein type, such as Eldorado in Canada and Shinkolobwe in the Belgian Congo. Those occurrences exhibited a high percentage of ores with uraninite and pitchblende featured as chief minerals. Over the past 5-6 years, a radical change has come about in the base of uranium raw materials in the capitalist countries. While in 1946 over 90% of the available uranium reserves were contained in occurrences of the vein type, in 1958 the role of occurrences of that type had dropped down to a level of 10%, with 90% of the reserves assigned to uraniferrous conglomerates and occurrences in sedimentary rock species (see Figure) [1]. These data confirm the deep significance attributed to occurrences of the sedimentary type in the solution of the problem of creating a raw materials base for uranium. This assertion is supported by the experience of geological exploration work in the USA, where the problem was entirely solved through the discovery of occurrances of the sandstone type such as Ambrosia Lake, Big Indian Wash, etc. Accompanying the change in the role of the particular types of occurrences, the significance of various uranium minerals has also undergone a change. In the USA, for instance, with the discovery of occurrences in New Mexico, the chief mineral for uranium is now coffinite [2]. The chief mineral in the Canadian Blind River deposits, reserves of which comprise about a third of the total uranium reserves available in capitalist countries,

1615