Practical Gamma-ray Spectrometry E-Book

Gordon Gilmore

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1283

Veröffentlichungsjahr: 2024

Beschreibung

The cutting-edge new edition of the classic introduction to radioactive measurement

Gammy-Ray Spectrometry is a key technique in the study of radioactive decay. It measures the rate and extent of radioactivity from a variety of sources, both natural and artificial, including cosmic ray sources, nuclear reactors, high-energy physics experiments, and more. The resulting data can be essential to environmental monitoring and to a range of experimental sciences.

For years, Practical Gamma-Ray Spectrometry has served as the classic introduction to this area for current or aspiring practitioners. A comprehensive but accessible treatment of the subject, with a thorough discussion of all major classes of detectors and their associated electronic systems, it contains everything a researcher needs to make optimal gamma-ray measurements. Now fully updated to reflect the latest technology and experimental data, it is a must-own for researchers looking to incorporate gamma-ray spectrometry into their scientific practice.

Readers of the third edition of Practical Gamma-Ray Spectrometry will also find:

• Fault-finding guide for rapid and effective problem resolution
• Workshop-style approach emphasizing the fundamentals of laboratory practice
• New sections dealing with novel developments in nuclear structure research, measuring effects of pollution and climate change, new semiconductor detectors, and more

Practical Gamma-Ray Spectrometry is ideal for PhD students and practicing gamma-ray spectroscopists, including researchers working on radiation, energy and environmental monitoring professionals, and researchers working in physics, archaeometry, and related subjects.

Leseprobe

Practical Gamma-ray Spectrometry

Third Edition

Gordon Gilmore

Honorary Professor

University of Liverpool

Liverpool, UK

David Joss

Professor of Physics

University of Liverpool

Liverpool, UK

This third edition first published 2024.© 2024 John Wiley & Sons Ltd

Edition History:John Wiley & Sons Ltd (1e, 1995 and 2e, 2008)

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The right of Gordon Gilmore and David Joss to be identified as the authors of this work has been asserted in accordance with law.

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In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging-in-Publication Data:

Names: Gilmore, Gordon, author. | Joss, David, author. | John

Wiley & Sons, publisher.

Title: Practical gamma-ray spectrometry / Gordon Gilmore, David Joss.

Description: Third edition. | Hoboken, NJ : Wiley, 2024. | Includes index.

Identifiers: LCCN 2024011669 (print) | LCCN 2024011670 (ebook) | ISBN

9781119896081 (hardback) | ISBN 9781119896098 (adobe pdf) | ISBN

9781119896104 (epub)

Subjects: LCSH: Gamma ray spectrometry.

Classification: LCC QC793.5.G327 G55 2024 (print) | LCC QC793.5.G327

(ebook) | DDC 537.5/352–dc23/eng/20240507

LC record available at https://lccn.loc.gov/2024011669

LC ebook record available at https://lccn.loc.gov/2024011670

Cover Design: Wiley

Cover Images: Courtesy of Gordon Gilmore

Preface to the Third Edition

Some years after the publication of the Second Edition of this book, I received an invitation to meet for lunch from Jenny Cossham, my contact within Wiley at the time. She assured me that she wouldn’t be asking me to prepare another edition so I could enjoy lunch – which I did. Since then, I have retired from all gamma spectrometry activities and spent much of my time on a delightful Greek island in the Aegean Sea. It was, therefore, not an unalloyed pleasure to receive an email in the summer of 2021 from Jenny suggesting that I might like to update ‘The Book’ for a third edition.

Being in my 80th year and not having had my hands on a gamma spectrometer for a considerable time and having no understanding of the latest developments in software and equipment, my first instinct was to refuse. However, after Jenny suggested the idea of making a joint venture to update the book with someone who was actively engaged in gamma spectrometry, I decided to consider the invitation. So, after meeting with David Joss, Professor at Liverpool University, and coming to an understanding about how much, or little, I was able to contribute, taking into account my long absence from active spectrometry, I decided to accept the commission and start work.

From the beginning, when John Hemingway and I wrote the first edition, the intention was to write a ‘plain man’s’ guide to gamma spectrometry, free of academic starch. A book that gave the impression that its content was the result of long practical experience in the laboratory. I think we achieved that, and, in this third edition, David and I have tried to stay true to that. Of course, most of the book deals with unchanging principles, so, necessarily, much of the second edition is unchanged. David has had the task of removing unnecessary out-of-date information and introducing our readers to more recent exciting developments. I am extremely grateful to David for doing that, as I am no longer in a position to do it myself.

In the second edition, I expressed a passion for quality issues in gamma spectrometry and tried to demonstrate that one cannot blindly trust the software we buy to analyse our spectra. While preparing this new edition, I was looking forward to finding out that the glaring problems within some of the software had been addressed. The reader will be able to judge if that was the case.

Within the book, I have frequently used FitzPeaks as a positive example of a spectrum analysis program. It was, therefore, with great sadness that I received news at the end of January 2023 that Jim Fitzgerald, the creator of FitzPeaks, had passed away.

Gordon Gilmore

The first edition of Practical Gamma-Ray Spectrometry by Gordon Gilmore and John Hemingway was published shortly after I started my doctoral research degree in nuclear physics. The book proved to be invaluable in providing a wealth of accessible practical knowledge for a fledgling gamma-ray spectroscopist. The second edition was released shortly after I became a lecturer, and it immediately became an essential reference text that I would recommend to my students. Indeed, I have bought many copies of the book over the years to replace those that found themselves on ‘long-term loan’ to students and colleagues. Practical Gamma-Ray Spectrometry has been a constant companion throughout my working life. When I was invited to work with Gordon Gilmore on the third edition, I was delighted to accept it without hesitation. It has been a pleasure to work with Gordon on this project. I am grateful to Jenny Cossham at Wiley for introducing me to Gordon and inviting me to contribute.

The underlying concepts and challenges in gamma-ray spectrometry that were discussed in earlier editions remain just as relevant today. It has been our aim to complement the discussion of those ideas with some of the recent developments in the field. The manufacturers of gamma-ray spectrometry systems have been very active since the publication of the second edition and have brought new technological innovations to the marketplace. These include small contact HPGe detectors that achieve excellent energy resolution and good efficiency over a broad energy range, new scintillator materials for gamma-ray detection and high-performance digital pulse processing systems. This is an exciting time for gamma-ray spectrometry and its applications.

I would like to acknowledge my colleagues at the University of Liverpool who have engaged in fruitful discussions about gamma-ray spectrometry, collaborated in measurements, or shared research data. In particular, I am indebted to Andy Boston, Helen Boston, Fraser Holloway, Dan Judson, Robert Page, Ellis Rintoul and Conor Sullivan.

David Joss

Preface to the Second Edition

During 2005, while this second edition was being prepared, I was totally unprepared to receive a telephone call that my co-author on the first edition, John Hemingway, was seriously ill after suffering a brain haemorrhage. Only a few days later, on 5th September, he passed away. My original, and obvious, intent was to update the sections allocated to John and myself and publish this second edition as ‘Gilmore and Hemingway’. That intent was frustrated by contractual difficulties with John’s estate. It became necessary for me to rewrite those sections completely and remove John’s name from the second edition. I deeply regret that that was necessary. It has deprived us all of John’s often elegant prose and has meant that some topics that John had particular interest in introducing to the new edition have had to be omitted.

Earlier in that year, another reminder of the inexorable passage of time came with the death of someone whose name had been familiar to me throughout my career in gamma spectrometry. On 16th January, Richard Helmer passed away at the age of 70 years. His co-authored work, the justly famous Gamma and X-Ray Spectrometry with Semiconductor Detectors, was one of the books that introduced John and myself to the complexities of gamma spectrometry and one which we consistently recommended to others. His influence as an author and in many other roles, such as an evaluator of nuclear data, has left all of us in his debt, whether we all realize it or not.

On a lighter note, during the year 2005 the very title of this book was called into question. The radiochemical mailing list, RADCH-L, agonized, in general terms, over which is the correct term – ‘spectrometry’ or ‘spectroscopy’. Of course, the suffix ‘-metry’ means to measure and ‘-scopy’ means to visualize – and so the discussion went on, to and fro. Eventually, the 1997 IUPAC ‘Golden Book’, Compendium of Chemical Terminology, was quoted: ‘SPECTROMETRY is the measurement of such [electromagnetic] radiations as a means of obtaining information about the system and their components’.

That seemed to be the ‘clincher’. The prime objective of our activities is to measure gamma radiation, not just to create a spectrum, and so spectrometry’ it is, performed by ‘gamma spectrometrists’!

Before a second edition is approved, the publishers canvass the opinion of people in the field as to whether a new edition is justified and ask them for suggestions for inclusion. I have taken all of the suggestions offered seriously but, in the event, have had to disappoint some of the reviewers. For example, X-ray spectrometry is such a wide field with a different emphasis than gamma spectrometry and the space available within this new edition is so limited that merely exposing a little more of the ‘iceberg’ seemed pointless. In other cases, my ignorance of certain specific matters was sufficient to preclude inclusion. I can only offer my apologies to those who may feel let down.

Since the first edition (1995), there have been a number of significant advances in gamma spectrometry. Indeed, some of those advances were taking place while I was writing, meaning re-writes even to the update! In particular, I have included digital pulse processing and I have explained the changes in the way that nuclear data are being kept up to date. On statistics, I have introduced the matter of uncertainty budgets as being of increasing importance now that more laboratories seek accreditation. I have had to re-assess the ideas I espoused in the first edition on peak width and now have a much more comfortable mathematical justification for fitting peak-width calibrations.

Throughout, I have tried to keep to the principles John and I declared in the Preface to the first edition – an emphasis on the practical application of gamma spectrometry at the expense of, if possible, the mathematics. That being the case, I have reproduced most of the preface to the first edition below. The first edition was very well received. I can only hope that I have done enough to ensure that popular opinion is as supportive of this second edition.

Gordon R. Gilmore

Preface to the First Edition

This book was conceived during one of the gamma spectrometry courses then being run at the Universities’ Research Reactor at Risley. At that time, we had been ‘peddling’ our home-spun wisdom for seven or eight years, and transforming the lecture notes into something more substantial for the benefit of course participants seemed an obvious development.

Our intention is to provide more of a workshop manual than an academic treatise. In this spirit, each chapter ends with a ‘Practical Points’ section. This is not a summary as such but a reminder of the more important practical features discussed within the chapter. We have attempted, not always successfully, it must be admitted, to keep the mathematics to a minimum. In most cases, equations are presented as faites accomplis and are not derived.

One practical process that can have a major influence on the reliability of the results obtained by users of gamma-spectrometric equipment is that of sampling. It was after much discussion and with some regret that we decided to omit this topic. This is because it is peripheral to our main concern of describing the best use of instrumentation, because we suspect that another book would be necessary to do justice to the subject and because we do not know much about it. What is clear is that an analyst must be aware that uncertainties introduced by taking disparate samples from an inhomogeneous mass can far outweigh uncertainties in the individual measurements themselves. This is a particular problem when sampling such a diverse and complex mass as the natural environment.

No previous knowledge of nuclear matters or instrumentation is assumed, and we hope the text can be used by complete beginners. There is even a list of names and symbols of the elements; while chemists may smile at this, in our experience not every otherwise scientifically literate person can name Sb and Sn or distinguish Tb and Yb.

In a practical book, we think it useful to mention particular items of commercial equipment to illustrate particular points. We must make the usual disclaimer that these are not necessarily the best, nor the worst, and in most cases are certainly not the only items available. In general, the manufacturers do a fine job, and choosing one product rather than another is often an invidious task. We can only recommend that the user (1) decides at an early stage what capabilities are required, (2) reads and compares specifications (this text should explain these), (3) is not seduced by the latest ‘whizz-bang device’, yet (4) bears in mind that more recent products are better than older ones, not just in ‘bald’ specification but also in manufacturing technology, and should consequently show greater reliability.

Readers may notice the absence of certain terms in common use. The exclusion of some such terms is a deliberate choice. For example, instead of ‘photopeak’ we prefer ‘full-energy peak’; we have avoided the statisticians’ use of ‘error’ to mean uncertainty and reserve that word to indicate bias or error in the sense of ‘mistake’. ‘Branching ratio’ we avoid altogether. This is often used ambiguously and without definition. In other texts, it may mean the relative proportions of different decay modes, the proportions of different beta-particle transitions, or the ratio of ‘de-excitation’ routes from a nuclear-energy level. Furthermore, it sometimes appears as a synonym for ‘gamma-ray emission probability’, where it is not always clear whether or not internal conversion has been taken into account.

We hope sensitive readers are not upset by our use of the word ‘program’. This ‘Americanized’ version is well on its way to being accepted as meaning specifically ‘computer program’, and enables a nice distinction to be made with the more general (and more elegant-looking) ‘programme’.

We have raided unashamedly the manufacturers’ literature for information, and our thanks are due particularly to Canberra and Ortec (in alphabetical order) for their cooperation and support in this. The book is not a survey of the latest research nor a historical study, and there are very few specific references in the text. Such that do exist are put at the end of each chapter, where there will also be found a more general short-list of ‘Further Reading’.

We also acknowledge our continuing debt to two books: Radiation Detection and Measurement, by G.F. Knoll, John Wiley & Sons, Ltd (1979, 1989) and Gamma- and X-Ray Spectrometry with Semiconductor Detectors, by K. Debertin and R.G. Helmer, North-Holland (1988).

These can be thoroughly recommended.

So why write another book? Fine as these works are, we felt that there was a place for a ‘plain-man’s’ guide to gamma spectrometry, a book that would concentrate on day-to-day operations. In short, the sort of book that we wish had been available when we began work with this splendid technique.

Gordon R. Gilmore and John D. Hemingway

Internet Resources Within the Book

Throughout this book, we list sources of information of value to gamma spectrometrists. The reality of modern life is that, for very many people, the Internet is the first ‘port-of-call’ for information. Because of this, we have leaned heavily on Internet sources and quoted links to them as standard URLs – Uniform Resource Locators, i.e. Internet addresses. URLs are usually not ‘case-sensitive’. However, that may depend on the type of server used to host the website. It is better to type the URL as given here, preserving upper/lowercase characters.

A word of caution is necessary. The Internet can be a source of the most up-to-date information and can be far more convenient than waiting for books and articles to be delivered or making a trip to a distant library. However, we feel duty bound to remind readers that, as well as holding up-to-date information, the Internet is also a vast repository of ancient, irrelevant, inaccurate and out-of-date information. It is up to the user to check the pedigree, and date, of all downloaded material. We believe the links that we have quoted to be reliable.

It is also said that once something gets on the Internet, it is there forever, that is not necessarily true, as we found out while checking the URLs in the Third edition of this book. Companies can cease to trade or be taken over and their domain name can be abandoned. Sometimes a website can be reorganized by a zealous new manager and information may still be on the website – but in a different place. So, the Internet is essentially an ephemeral entity.

The Practical Gamma-Ray Spectrometry Companion Website, written for the Second Edition by Gordon Gilmore, has been updated for the Third Edition. It carries links to most of the websites referred to in the book, test spectra (or links to them), and some of the spreadsheets used to create the diagrams and data in the book. It also carries a Corrections Page, where readers who find typographical or factual errors can report them to the Publisher and the authors.

The address of the Companion Website is: www.wiley.com/go/Gilmore/PracticalGammaraySpectrometry3e.

About the Website

www.wiley.com/go/Gilmore/PracticalGammaraySpectrometry

1Radioactive Decay and the Origin of Gamma and X-Radiation

1.1 Introduction

In this chapter, I intend to show how a basic understanding of simple decay schemes, and of the role gamma radiation plays in these, can help in identifying radioactive nuclides and in correctly measuring quantities of such nuclides. In doing so, I need to introduce some elementary concepts of nuclear stability and radioactive decay. X-radiation can be detected by using the same or similar equipment, and I will also discuss the origin of X-rays in decay processes and the light that this knowledge sheds on characterization procedures.

I will show how the Karlsruhe Chart of the Nuclides can be of help in predicting or confirming the identity of radionuclides, being useful both for the modest amount of nuclear data it contains and for the ease with which generic information as to the type of nuclide expected can be seen.

First, I will briefly look at the nucleus and nuclear stability. I will consider a nucleus simply as an assembly of uncharged neutrons and positively charged protons; both of these are called nucleons.

Z is the atomic number and defines the element. In the neutral atom, Z