RADu0130OACTu0130VE DECAY HANDBOOK.pdf - DOE/TIC 1 1026...

Unformatted text preview: DOE/TIC- 1 1026 A Handbook of Decay Data for Application to Radiation Dosimetry and Radiological Assessments David C. Kocher Office of Scientific and Technical Information U. S. DEPARTMENT OF ENERGY ABOUT THE OFFICE OF SCIENTIFIC AND TECHNICAL INFORMATION The Department of Energy’s Scientific and Technical Information Program (STIP) is carried out at many levels within the Department and by its contractor organizations. The Office of Scientific and Technical Information (OSTI) in Oak Ridge, Tennessee, provides direction and leadership for STlP and serves as DOE’s national center for scientific and technical information management and dissemination. Both DOE-originated information and worldwide literature regarding advances in subjects of interest to DOE researchers are collected, processed, and disseminated through an energy information system maintained by OSTI. The major data bases in this system are available within the United States through commercial on-line systems and to those outside the United States through formal governmental exchange agreements. The current-year records for the major data base, plus a number of specialized data bases, are available to DOE offices and contractors through OSTl’s Integrated Technical Information System (ITIS). ITIS also serves as a gateway to other government and commercial systems and provides information merging for customized information products. To manage DOE‘s informotion resources effectively, DOE‘s Scientific and Technical Information Program is one of continual development and evaluation of new information products, systems, and technologies. . DISCLA1MER This report was prepared as an account of work sponsored by an agency of the United States Government. 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DOE/TIC-1 1026 (DE81002999) A Handbookof Decay Data for Application to Radiation Dosimetry and Radiological Assessments David C.Kocher Health and Safety Research Division Oak Ridge National Laboratory 1981 _. Published by Office of Scientific and Technical Information U. S. DEPARTMENT OF ENERGY Library of Congress Cataloging in Publication Data Kocher, David C. Radioactive decay data tables. “DOE/TIC-11026” 1 . Radioactive decay-Tables. [ D N LM: 1. Radioactivity-Tables. QC795.8.D4K62 539.7’5 ISBN 0-87079-124-9 AACR2 I. Title. WN 16 K76r] 81 -607800 Available as D E 8 1 0 0 2 9 9 9 National Technical Information Service U S. Department of Commerce 5 2 8 5 Port Royal Road Springfield, Virginia 2 2 1 6 1 D O E Distribution Category U C - 4 1 Price Code: Paper Copy A 1 1 Microfiche A 0 1 Printed in the United States of America April 1981; latest printing November 1988 Radioactive D e c a y Data Tables occupationally exposed individuals. Approximately 500 radionuclides are contained in the current data base, and our recent experience suggests that almost all radionuclides o f potential impact on the general public or occupationally exposed individuals have been included. The data for each radionuclide have been maintained on an up-to-date basis by examination of all recent experimental results published in the open literature and incorporation of these results into the data base whenever warranted. The data base takes into account all experimental results reported t o me prior t o July 1, 1979. Several compilations o f radioactive decay data similar in some respects to this one have been published in recent years. Particularly noteworthy are the compilations by L. T. Dillman and F. C. Von der Lage, published in 1975 in Pamphlet No. 10 of t h e Medical Internal Radiation Dose Committee, and M. J. Martin of the Nuclear Data Project, published in 1978 in Report No. 58 of the National Council on Radiation Protection and Measurements. The proliferation of published compilations containing data for large numbers of radionuclides i s testimony to the successful application of computers to the processing of data bases of this type. In spite of the apparent similarities between the different compilations, there are some differences of importance t o potential users o f the data. The most obvious i s the particular selection of radionuclides. More subtle differences may result from the various methods used t o select and evaluate data from the literature and t o prepare the data sets. It is worth emphasizing that there i s a considerable degree o f subjectivity in this process and two knowledgeable compilers can therefore produce somewhat different decay schemes for a given radionuclide starting from This compilation of radioactive decay data culminates 8 years of effort in the field of nuclear d a t a compilation and evaluation. During the first 4'/2 years of this time, I worked with the Nuclear Data Project in the Physics Division a t Oak Ridge National Laboratory (ORNL). The primary interest of this group i s the evaluation of a wide variety of nuclear physics data t o determine the structure and properties of atomic nuclei, and i t s most visible contribution t o nuclear structure physics is the mass-chain evaluations published in the journal Nuclear Data Sheets. In 1976, I joined the Technology Assessments Section of the Health and Safety Research Division a t ORNL. Since that time I have been concerned with the evaluation and compilation of radioactive decay data from the point of view of i t s application t o radiation dosimetry and radiological assessments. Initially, I prepared a data base of evaluated decay data for 240 radionuclides of potential importance in the nuclear fuel cycle. This data base was adopted for use by the U. S. Nuclear Regulatory Commission, and the data were published in August 1977 as the report ORNL/NUREG/TM:102. The radioactive decay _data tabulated in this handbook result from the continual expansion and updating of the data base published in the aforementioned report. I n addition t o the radionuclides of interest in the nuclear fuel cycle, the data base now comprises most of the nuclides occurring naturally in the environment, those of current interest in nuclear medicine and fusion reactor technology, and some (but hardly all!) additional radionuclides of interest t o Committee 2 of the International Commission on Radiological Protection for the estimation of annual limits of intake and derived air concentrations for iii the same data in the literature. We note, however, that the differences would likely be within experimental uncertainties unless the decay scheme is poorly determined from the data. In the preparation of the decay data in this handbook, the fundamental principle has been to critically evaluate the available data from all source! in the open literature and attempt to construct the most accurate decay scheme consistent with the data rather than simply to adopt a decay scheme proposed by another compiler or experimenter without further examination. The evaluation process i s not always foolproof, however, since the compiler is occasionally faced with reconciling or choosing between disparate sets of data, and the choices made may not prove to be correct. It is clear, therefore, that the biases of the compiler can play an important role in the process of selecting and evaluating data. It is hoped that my biases and data-evaluation philosophy have been applied reasonably consistently to obtain the adopted data sets for all the radionuclides contained herein. I cannot overemphasize the importance of the contributions of the staff of the Nuclear Data Project and other compilers who have published mass-chain compilations in the journals Nuclear Data Sheets and Nuclear Physics t o the successful completion of this work. I am particularly grateful to W. B. Ewbank, director of the Nuclear Data Project, for his continual assistance and cooperation throughout this effort. The Nuclear Data Project maintains a computer file called the Evaluated Nuclear Structure Data File (ENSDF). Radioactive decay data sets written in the ENSDF format were used t o generate the tables of decay data given in this handbook. When work on this compilation began early in 1976, much of the radioactive decay data previously published in Nuclear Data Sheets and Nuclear Physics had not yet been entered in ENSDF. Consequently considerable effort was required on my part to prepare many of the data sets in the proper format. In the meantime, however, ENSD F has been expanded to currently include more than 1500 radioactive decay data sets. I f a compiler were to begin now to assemble a compilation such as the one presented in this handbook, he or she would be able t o rely almost exclusively on data sets already contained in ENSDF, and little additional effort in evaluating data and producing new data sets would be required. Thus it is my intention in the future to rely on ENSDF rather than continually updating a separate data base of my own to provide additional radioactive decay data that might be needed in the radiological assessment activities of the Health and Safety Research Division. It is worth noting that, with few exceptions, the decay data contained in this handbook are not likely to change significantly over the next few years as the result of new measurements. Most of the decay schemes have been studied with reasonable care and accuracy, and only minor improvements in the data of l i t t l e significance for radiological applications can be expected. Thus I anticipate that the data contained in this handbook and in other recent compilations can be used with confidence for a considerable period of time. I would like to express my appreciation to G. G. Killough, R. 0. Chester, P. S. Rohwer, and S. V. Kaye of the Health and Safety Research Division a t ORNL and to F. Swanberg, Jr., of the Division of Safeguards, Fuel Cycle, and Environmental Research a t the Nuclear Regulatory Commission for their support and encouragement of this effort. This research was sponsored by the Office of Nuclear Regulatory Research, U. S. Nuclear Regulatory Commission, under Interagency Agreement DOE 40-550-75 with the U. S. Department of Energy under contract W-7405-eng-26 with the Union Carbide Corporation. David C. Kocher Health and Safety Research Division Oak Ridge National Laboratory Radioactive Decay Data Tables Preface Chapter 1 Introduction References Chapter 2 Review of Radioactive Decay Processes 2-1 Alpha Decay 2-2 Beta Decay 2-3 Electromagnetic De-Excitation of Nuclear Energy Levels 2-4 Atomic Radiations References Chapter 3 Preparation of Radioactive Decay Data Sets 3-1 ENSDF Formats 3-2 Preparation of Decay Data Sets References Chapter 4 Computer Code MEDLIST and Description of Tables of Radioactive Decay Data Reference Chapter 5 Applications of Decay Data to Radiation Dosimetry and Radiological Assessments References ... Chapter 6 Parent-Daughter Activity Ratios References 111 1 2 3 3 4 5 7 8 9 9 11 20 20 Chapter 7 Accuracy of the Data and Uncertain Decay Schemes 7-1 Uncertain Decay Data for Radionuclides from the Nuclear Fuel Cycle 7-2 Uncertain Decay Schemes for Other Radionuclides Reference 23 25 Appendix 1 Symbols and Definitions 26 Appendix 2 Index t o Tables of Radioactive Decay Data 27 Appendix 3 References for Radioactive Decay Data Sets 36 Appendix 4 Diagrams of Radioactive Decay Chains 49 Appendix 5 Tables of Radioactive Decay Data 68 21 21 14 15 17 18 19 V Introduction of the discussion in Chaps. 2 and 3 i s probably not comprehensible t o readers lacking a basic knowledge of atomic and nuclear structure. Without deviating substantially from the scope of this handbook, it is difficult t o adequately define such concepts as spin and parity, gamma-ray transition multipolarity, forbiddenness of beta transitions, and energy levels of nuclei and orbital atomic electrons. The inclusion of the material of a specialized nature should provide the interested reader with a reasonably self-contained description of the decay data and how they were obtained, but these discussions should not preclude proper interpretation of the data tables by any interested user. Chapter 4 describes the tables of radioactive decay data and the computer code MEDLIST used to produce the table^.^ Some applications of the radioactive decay data t o problems of interest in radiation dosimetry and radiological assessments a r e described in Chap. 5. The calculation of the activity of a daughter radionuclide relative t o the activity of i t s parent in a radioactive decay chain is described in Chap. 6. Chapter 7 discusses the accuracy of the decay data in this handbook with particular emphasis on radionuclides for which the data may be significantly in error with regard to applications to radiation dosimetry. The symbols appearing in the tables of decay data and their definitions are listed in Appendix 1. Appendix 2 provides an index of the tables o f radioactive decay data, and Appendix 3 contains the literature references on which the tables are based. Appendix 4 gives diagrams of all decay chains involving two or more raldionuclides in the present compilation. The tables of radioactive decay data are presented in Appendix 5. The estimation of radiation dose to man from either external or internal exposure t o radionuclides requires a knowledge of the energies and intensities of the atomic and nuclear radiations emitted during the radioactive decay process. The availability of evaluated decay data for the large number of radionuclides of interest is thus of fundamental importance for radiation dosimetry. This handbook contains a compilation of decay data for approximately 500 radionuclides. These data constitute an evaluated data file that I have constructed for use in the radiological assessment activities of the Technology Assessments Section of the Health and Safety Research Division a t Oak Ridge National Laboratory. -- The radionuclides selected for this handbook include those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and fusion reactor technology, and some of those of interest to Committee 2 o f the International Commission on Radiological Protection for the estimation of annual limits on intake via inhalation and ingestion for occupationally exposed individuals. This handbook supersedes a previous report,' which was concerned only with radionuclides from the nuclear fuel cycle. The physical processes involved in radioactive decay which produce the different types of radiation observed are discussed in Chap. 2. The methods used t o prepare the decay data sets for each radionuclide in the format of the computerized Evaluated Nuclear Structure Data File (ENSDF),2 developed and maintained by the Nuclear Data Project a t Oak Ridge National Laboratory, are described i n Chap. 3. Some 1 This handbook is one of several similar compilations of radioactive decay data which have appeared in recent years. Particularly recommended is the compilation by Dillman and Von der Lage,4 which contains data for 122 radionuclides o f interest t o nuclear medicine, and the compilation prepared by M. J. Martin of the Nuclear Data Project for the National Council on Radiation Protection and Measurement~,~which contains data for about 210 radionuclides of interest primarily t o nuclear medicine and the nuclear fuel cycle. I have independently reevaluated decay data for all radionuclides in the previous compilations which are included in this compilation. REFERENCES 1. D. C. Kocher, Nuclear Decay Data for Radionuclides Occurring in Routine Releases from Nuclear Fuel Cycle 2 RADIOACTIVE DECAY DATA TABLES Facilities, ERDA Report ORNL/NUREG/TM-102, Oak Ridge National Laboratory, 1977, NTIS. 2. W. B. Ewbank and M. R. Schmorak, Evaluated Nuclear Structure Data File-A Manual for Preparation of Data Sets, ERDA Report ORNL-5054/RI, Oak Ridge National Laboratory, 1978, NTIS. 3. M. J. Martin (Ed.), Nuclear Decay Dara for Selected Radionuclides, ERDA Report ORNL-5114, Oak Ridge National Laboratory, 1976, NTIS. 4. L. T. Dillman and F. C. Von der Lage, Radionuclide Decay Schemes and Nuclear Parameters for Use in RadiationDose Estimation, Pamphlet I O , Society of Nuclear Medi- cine, New York, 1975. 5. National Council on Radiation Protection and Measure- ments, A Handbook of Radioactivity Measurements Procedures, Report No. 58, 1978. Review of Radioactive Decay Processes The term "radioactivity" denotes those spontaneous changes of state in atomic nuclei which release energy in the form of electromagnetic or particle radiations. This chapter discusses briefly the different radioactive decay processes in sufficient detail to allow an understanding of the tables in Appendix 5. This presentation and the discussions in Chaps. 4 and 6 follow closely those given previously by Martin.' J For examples of more-detailed discussions of radioactive decay processes, the reader i s referred t o the report by Dillman3 and the reference work of Siegba hn.4 In this compilation we are concerned with alpha decay, beta decay [including /3-, /3+, and electron capture (EC)], isomeric transitions (i.e., the decay of long-lived excited states of a nucleus t o states of lower energy i n the same nucleus), and the various atomic and nuclear radiations that accompany these processes. Nuclear radiations are those which result directly from a change of state of the nucleus and include alpha particles, 0- and 0' particles; gamma rays, and internal conversion electrons. Atomic radiations are those which result from the subsequent changes of state of the orbital electrons-in the daughter atom and include X rays and Auger electrons. A radioactive decay process not considered in this compilation i s spontaneous fission, which can be the most important mode of decay in terms of total energy released for some of the transuranic radionuclides. Methods for estimating energy distributions of neutrons, prompt and delayed gamma rays, and beta particles, as well as the average energies of these radiations, have been given by Dillman and Jones.' A type of radiation also not considered in this compilation i s bremsstrahlung, which is the gamma radiation produced when electrons emitted in radioactive decay are slowed down by passage through matter. Bremsstrahlung forms a continuous spectrum of energies ranging from zero energy to the kinetic energy of the emitted electron with the intensity distribution considerably skewed toward the lower energies. Intensities of bremsstrahlung from slowing down of alpha particles and other heavy charged particles, such as recoil nuclei and fission fragments, are expected to be very small compared with electron bremsstrahlung. Bremsstrahlung consists of two types, external and internal. External bremsstrahlung results from the interaction of the emitted electrons with the atoms in the material surrounding the radiating atom; so i.he energy spectrum depends on the atomic composition of the surrounding medium. In some cases, particularly for radionuclides that emit only beta particles, external bremsstrahlung can be of importance in radiation ...
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