Appl. Radiur hi. Vol. 37, No. 4, p. 363, 1986 In/ J. Ruhar. A/I/J/. Instrum. Port A Pergamon Press Ltd. Prmted in Great Britain

BOOK REVIEW

A Handbook of Radioactivity Measurement Procedures (NCRP Report No 58, 2nd edition). Published by NCRP, Bethesda, Maryland, U.S.A. (1985). ISBN o-913392-71-5. USS 25 (hard cover). 592 pp.

The book reviewed here is the second edition of a report issued in 1978 which was itself a complete update of one of three parts of NCRP Report No 28, A Manual of Radia- actit>ily Procedures, originally issued in 1961. This hand- book is aimed mainly at users in environmental, medical and industrial laboratories, the objective being to enable such laboratories to make quantitative measurements of the radioactivity of solid, liquid and gaseous sources (but excluding neutron emitters and fission sources) which may arise in the course of their work. The handbook will be of use mainly to users rather than to designers of equipment and, in particular, to those who are concerned in achieving the greatest possible precision and absolute accuracy in their measurements.

The first chapter provides a brief descriptive introduction to the interaction of radiation with matter and to the various methods by which radioactivity standards may be measured, The second deals at some length with the physics of many forms of radiation detector, from the current ionization chamber to the semiconductor and Cerenkov detectors, in a qualitative way. The final section of this chapter however deals in some detail with corrections due to dead times, source decay and backgrounds.

The third and fourth chapters deal in much greater detail with the determination of radioactivity by direct and indi- rect methods respectively and in the many expected and unexpected ways by which measurements can go wrong, More than 80% of chapter 3 is devoted to counting techniques and well over half of chapter 4 to gamma ray spectroscopy. Here even the experienced technician or sci- entist cannot fail to learn something new. not only in the depth but also in the breadth of the treatment of the methods described.

The fifth is a brief chapter on the preparation of sources and can only be regarded as an introduction to the difficulties involved in such undertakings.

The greater part of chapter 6 is devoted to the problems associated with low level measurements, which are many and various, but it begins with an expanded recapitulation of certain aspects of chapter I, including in particular valuable discussions of detection limits, background and other factors affecting the choice of particular techniques for particular problems. This is followed by brief sections on the supply of radioactive materials, user’s responsibility for quality control and the equipment needed in the well- equipped laboratory for radioactivity measurements, and a longer one on the assay of radiopharmaceuticals.

Chapter 7 is devoted to the statistics relevant to counting, particularly at low counting rates, and includes valuable discussions on the statistical design of experiments and on

the exact meanings of the terms precision, s~sremic error and

uncerrainrj~ which are followed up in the next chapter on Measurement Assurance, Standards, Traceability and the Statement of Uncertainty. Chapter 8 is significantly longer than in the first edition, particularly in the sections dealing with measurement assurance, traceability and uncertainty, which are almost completely new.

Then follow 150 pages of selected nuclear decay data, a brief appendix on the statistics of radioactive decay, about 700 references of which some 15% post-date the first edition, and some information on NCRP. The references are of course an essential feature of the book, for a very great deal of the detail necessary for more than a qualitative understanding of the text is to be found in the material referred to.

So we have here an extremely useful book, particularly for a person or a laboratory entering this field of work for the first time. One of the more important features is that periodically through the book it is manifest that effective measurement is almost as much an art as it is a science or technology.

However there are few points with which one can legiti- mately find fault, It is disappointing not to find SI units adhered to throughout the text (e.g. chapter 6) nor to find any approximate figure for the sea-level cosmic ray flux which can be an important contribution to the background in low counting rate experiments. Neutron induced activa- tion is very sketchily treated and neutron-induced effects in detectors are ignored completely-and they could be im- portant where measurements need to be made in the vicinity of strong neutron sources. The legibility of Figs 41 and 59 is unsatisfactory because the lettering is too small on the former and obscured by the background grid on the latter. The index seems very short for a book of this size and, for example, cosmic radiation. kerma and neutrons are absent from it as primary entries, It would have been helpful to the reader if the page numbers of tables were at the point in the text where they are referred to, for there are only 21 tables in 360 pages, excluding appendices, and at times the tables are more than a hundred pages away from the place of reference.

However one must not end this review on a note of carping criticism of minor matters, for the new edition is to be highly recommended, particularly to new entrants to this field of work. The book, whose technical level advances rapidly as one progresses from Chapter I to Chapter 8. clearly shows that the work involved in highly accurate measurement has its own beautiful inner logic and presents a great challenge that can be as satisfying to many people as the exploration of the frontiers of physics is to others.

BASIL ROSE Ahingdon

U.K.

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