Bibliography

V. Veksler, L. Groshev, and B. Isaev. Ionization Methods for the Study of Radiation. State Publishing House of Technical-Theoretical Literature, Moscow—Leningrad, 1949. 424 pp. Price 16 rubles 95 kopecks.

The last decade has been a period of rapid development in the technique of studying nuclear radiation. It is enough to recall the universal introduction of Geiger–Müller counters into laboratory practice, the creation of photographic emulsions sensitive to relativistic particles, the development of crystal, scintillation, plane-parallel, bolometric, and other new types of counters, the application of ionization chambers operating on an electron pulse, and so on. During this same time, finally, much work was carried out on studying the mechanism of operation of Geiger–Müller counters, leading to the creation of a theory of the operation of these counters that is well confirmed by experiment.

If ten years ago it was possible to give a detailed account of the basic methods of nuclear physics within the limits of a single book, the development of these methods noted above has now made the accomplishment of this task a matter of considerable difficulty. This circumstance apparently led the authors of the book Experimental Methods of Nuclear Physics, published ten years ago, to abandon the attempt at a simple “modernization” of it. In the new monograph, as its title indicates, only those methods of recording radiation are considered which are based on the direct measurement of electrical pulses caused by the rays under investigation.

The book is divided into two parts. In the first part, ionization chambers are considered. After setting forth the basic principles of operation of ionization chambers, the chambers used for recording α-, β-, γ-, X-, and cosmic rays and neutrons are examined separately. Attention is given to the methodological features of recording each of these types of radiation—to the influence of the walls, pressure, and nature of the gas, the voltage on the electrodes, the character of ionization inside the chamber, and so forth. Briefly considered are counting ionization chambers and, in particular, chambers operating on an electron pulse.

The second part of the book is divided into two sections. In the first section proportional counters are considered, and in the second, separately, non-self-quenching and self-quenching counters. The authors of the book are widely known for their work on the investigation of the properties of Geiger counters and, in particular, proportional counters. The inclusion of numerous works by the authors and their students, as well as by other Soviet researchers—

...readers is a considerable advantage of the monograph under review over similar foreign books.

The main attention in the second part of the book is devoted to an analysis of the discharge mechanism in all three types of counters and to determining the influence of various factors on this mechanism (the role of photons, the significance of secondary electron emission at the cathode, etc.). For all three types of counters, the question of the form of the pulse is examined in detail, and the reader interested in this important question of the operation of counters will find a clear and exhaustive exposition of it. However, the reader will find few indications of a practical nature that would help him construct a reliably operating counter or understand the vagaries of an existing counter.

The section devoted to self-quenching counters also includes such questions as artificial quenching of the discharge (although this question pertains above all to non-self-quenching counters), X-ray, cosmic-ray, and γ-ray counters, scintillation counters, counters with a small gas pressure, and β-particle counters.

The book concludes with a section devoted to the theory of corrections for individual counters and for counters operating in coincidence.

Undoubtedly, the selection of material for a monograph devoted to a rapidly developing scientific question is no easy task. This, probably, explains why disproportionately great attention has been given to some questions, while other questions, of great scientific and practical interest, are treated very superficially or passed over altogether. Thus, for example, more than 15 pages are devoted to the transition effects of γ-rays in ionization chambers, whereas the measurement of β-particles—“one of the most frequently encountered practical problems,” according to the authors—is given only 6 pages; the long § 38, which gives a detailed mathematical derivation of the distribution of paths of fast particles passing through two cylindrical counters connected in coincidence, is unlikely to be of great theoretical or practical interest to most readers (especially since the entire derivation has been published in a specialized public journal), while, for example, the extremely interesting question of obtaining data on the energy and character of particle ionization in counting-ionization chambers from the pulse shape is not considered at all.

An analysis of various tube circuits was not part of the authors’ task, and therefore such circuits are considered only insofar as they directly influence the mechanism of the counter discharge. Accordingly, only quenching and reversing circuits are considered.

The book contains many calculations that clearly explain the physical essence of the phenomena occurring in chambers and counters. It should be noted that the calculation given in § 27 to illustrate the influence of photons on the quenching coefficient in a proportional counter is erroneous, since the multiplication factor for photoelectrons produced at the cathode or in the gas of the counter is not taken into account. The same formula is derived a second time in § 32 as a special case of a more general formula, and, although the latter is written correctly, the authors derive from it (not mathematically!) the same incorrect formula that is given in § 27 [formula (31) on p. 215]. In general it must be pointed out that the value of this calculation is small, since the assumption that the probability of formation of a photoelectron in the subsequent avalanche by one electron of the preceding avalanche does not depend on the number of the avalanche is implausible, if one takes into account that the field strength decreases with each subsequent avalanche.

Among other errors present in the monograph, it should be noted that in Landau’s formula for calculating the most probable ionization,

produced by a relativistic particle as it passes through a specified layer of matter of thickness \(x\) (p. 218); \(n\) denotes Avogadro’s number, and not the number of electrons in a cubic centimeter, as is asserted in the book, and the thickness of the layer is expressed not in \(\mathrm{g/cm^2}\), but in centimeters.

On p. 281 it is asserted that “the role of the high-ohmic resistance \(R\) obviously consists in preventing the charge from flowing off the capacitance,” whereas in fact the purpose of this resistance is precisely the opposite.

On p. 359 it is noted that the counting characteristic of a self-quenching counter, satisfactorily operating at high-ohmic resistance, may have a large slope when operating in a quenching circuit, but it is not noted, as was pointed out by Kozodaev and Latyshev, that a multivibrator quenching circuit may also improve the characteristics of counters.

It should finally be pointed out that a certain lack of coordination between individual parts of the book is felt. Let us give one example. In analyzing the mechanism of discharge in a proportional counter, a simple derivation is given on one and a half pages of the relation between the potential of the filament and the position of the positive space charge [formula (16), p. 198]. This same formula is derived a second time in the treatment of self-quenching counters [formula (26), p. 275], the derivation now taking more than four pages, and it is not noted that this formula is identical with the one derived earlier.

The noted shortcomings of the book, which are rather in the nature of misprints, cannot diminish its high scientific level. The authors have succeeded in giving an exhaustive picture of the phenomena occurring in ionization chambers and counters in the registration of nuclear radiations, and also in setting forth the basic methodological features that arise in work with one or another instrument. It may confidently be said that the book under review will become an indispensable aid for every experimenter actively working with Geiger–Müller counters or with ionization chambers.

L. Bell