National and International Standardization of Radiation Dosimetry PROCEEDINGS OF A SYMPOSIUM ATLANTA 5 -9 DECEMBER 1977 V tTj? INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1978 >*___¿I? NATIONAL AND INTERNATIONAL STANDARDIZATION OF RADIATION DOSIMETRY VOL.II The following States are Members of the International Atomic Energy Agency: AFGHANISTAN HOLY SEE PHILIPPINES ALBANIA HUNGARY POLAND ALGERIA ICELAND PORTUGAL ARGENTINA INDIA QATAR AUSTRALIA INDONESIA ROMANIA AUSTRIA IRAN SAUDI ARABIA BANGLADESH IRAQ SENEGAL BELGIUM IRELAND SIERRA LEONE BOLIVIA ISRAEL SINGAPORE BRAZIL ITALY SOUTH AFRICA BULGARIA IVORY COAST SPAIN BURMA JAMAICA SRI LANKA BYELORUSSIAN SOVIET JAPAN SUDAN SOCIALIST REPUBLIC JORDAN SWEDEN CANADA KENYA SWITZERLAND CHILE KOREA, REPUBLIC OF SYRIAN ARAB REPUBLIC COLOMBIA KUWAIT THAILAND COSTA RICA LEBANON TUNISIA CUBA LIBERIA TURKEY CYPRUS LIBYAN ARAB JAMAHIRIYA UGANDA CZECHOSLOVAKIA LIECHTENSTEIN UKRAINIAN SOVIET SOCIALIST DEMOCRATIC KAMPUCHEA LUXEMBOURG REPUBLIC DEMOCRATIC PEOPLE’S MADAGASCAR UNION OF SOVIET SOCIALIST REPUBLIC OF KOREA MALAYSIA REPUBLICS DENMARK MALI UNITED ARAB EMIRATES DOMINICAN REPUBLIC MAURITIUS UNITED KINGDOM OF GREAT ECUADOR MEXICO BRITAIN AND NORTHERN EGYPT MONACO IRELAND EL SALVADOR MONGOLIA UNITED REPUBLIC OF ETHIOPIA MOROCCO CAMEROON FINLAND NETHERLANDS UNITED REPUBLIC OF FRANCE NEW ZEALAND TANZANIA GABON NICARAGUA UNITED STATES OF AMERICA GERMAN DEMOCRATIC REPUBLIC NIGER URUGUAY GERMANY, FEDERAL REPUBLIC OF NIGERIA VENEZUELA GHANA NORWAY VIET NAM GREECE PAKISTAN YUGOSLAVIA GUATEMALA PANAMA ZAIRE HAITI PARAGUAY ZAMBIA PERU The Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is “ to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world” . Printed by the IAEA in Austria December 1978 PROCEEDINGS SERIES NATIONAL AND INTERNATIONAL STANDARDIZATION OF RADIATION DOSIMETRY PROCEEDINGS OF AN INTERNATIONAL SYMPOSIUM ON NATIONAL AND INTERNATIONAL STANDARDIZATION OF RADIATION DOSIMETRY HELD BY THE INTERNATIONAL ATOMIC ENERGY AGENCY IN ATLANTA, GEORGIA, 5 -9 DECEMBER 1977 In two volumes VOL.II INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1978 EDITORIAL NOTE The papers and discussions have been edited by the editorial staff o f the International Atomic Energy Agency to the extent considered necessary for the reader's assistance. The views expressed and the general style adopted remain, however, the responsibility o f the named authors or participants. In addition, the views are not necessarily those o f the governments o f the nominating Member States or o f the nominating organizations. Where papers have been incorporated into these Proceedings without resetting by the Agency, this has been done with the knowledge o f the authors and their government authorities, and their cooperation is gratefully acknowledged. The Proceedings have been printed by composition typing and photo-offset lithography. Within the limitations imposed by this method, every effort has been made to maintain a high editorial standard, in particular to achieve, wherever practicable, consistency o f units and symbols and conformity to the standards recommended by competent international bodies. The use in these Proceedings o f particular designations o f countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status o f such countries or territories, o f their authorities and institutions or o f the delimitation o f their boundaries. The mention o f specific companies or o f their products or brand names does not imply any endorsement or recommendation on the part o f the IAEA. Authors are themselves responsible for obtaining the necessary permission to reproduce copyright material from other sources. NATIONAL AND INTERNATIONAL STANDARDIZATION OF RADIATION DOSIMETRY IAEA, VIENNA, 1978 STI/PUB/471 ISBN 9 2 - 0 - 0 1 0 5 7 8 - 5 FOREWORD Public concern about all aspects of radiation safety has generated a strong demand for reliable measurement of ionizing radiation, a demand that applies not only to the protection of man and his environment but also to those activities in which radiation work plays an essential role — in medicine, nuclear power, industrial radiation processing and scientific research. All these require regulation of some kind, and in many countries new or revised rules have been issued concerning the use of ionizing radiations, leading to a requirement for standardization in dosimetry on both the national and international levels. The introduction of the international system of units (SI) in the field of radiation measurement has engendered a critical appraisal of the concepts and quantities as well as of the units. This has coincided with a period in which a transition in outlook is apparent — there being a movement away from the quantity exposure towards the quantity absorbed dose (or air-kerma) for appropriate radiation qualities. Thus it seemed timely to reconsider and discuss the realization of the primary radiation units and their dissemination through the entire calibration chain to provide practical units for accurate measurements in the field. It had also become clear that, in order to widen the availability — both geographically and numerically - of calibrated radiation measuring apparatus, the efforts of the national primary standards laboratories would have to be supplemented. In some of the larger industrialized countries, enlarged schemes for providing calibration services have had to be set up, with the national standards laboratory as the primary reference centre. For many countries now entering the field of nuclear energy, or using radiation in medicine and industry, the settingup of Secondary Standard Dosimetry Laboratories (SSDLs) appeared to provide the most suitable and economic solution to the problem of dis­ seminating radiation units. The SSDL’s role is to calibrate tertiary and field dose meters and to serve as the necessary link between the primary standards laboratories and the radiation user. The world-wide spread of such SSDLs — within the frame of the IAEA/WHO Network of SSDLs — gives rise to a need for them to collaborate with each other and with primary standards labora­ tories to ensure that standards are truly uniform. When preparing the Symposium on the National and International Standardization of Radiation Dosimetry, it therefore seemed appropriate to discuss, in addition to primary standards and the work of primary standards laboratories, the specific tasks of SSDLs, the presentation of results and uncertainties throughout the calibration chain, as well as the organization and results of dose intercomparisons such as those initiated by international, regional and national laboratories. In this context a discussion on national and inter­ national standards for the performance of dose meters, and the procedures for verification and type testing also seemed to be very relevant. It is imperative that work on the basic physics phenomena related to dosimetry be continued and discussed at international meetings. Basic data, characterizing the interaction processes between radiation and matter, enter into the calibration chain; this requires international standardization of the numerical values. Here again it becomes evident that the task of the standard­ izing laboratories cannot be confined to calibrations of secondary or tertiary standard dose meters against primary or secondary standards, respectively; it must include a follow-up of the entire chain of dissemination of the radiation unit, providing the ultimate user with a clear instruction on how to determine the absorbed dose at a specified point from the reading of the instrument. In the field of medicine, codes of practice for radiation therapy dosimetry with photon and electron radiation have been issued by a number of national and international committees. Some of these recommendations are at present under review or are the subject of revision. New formalisms have been suggested which might replace the widely used exposure calibration factor and the dose conversion factors. This new approach seems not only to be more con­ sistent and accurate, it leads also to a unified procedure for photon and electron radiation. Progress in standardization of radiation dosimetry is closely related to the activities of the International Commission on Radiation Units and Measure­ ments (ICRU). Involved in this subject ever since 1925, the ICRU has had more impact on standardization in radiation measurement than any other organiza­ tion. At present, one of the activities of ICRU is to provide information on the various factors needed for calculating the basic physical properties of absolute radiation standards. Of the ten sessions of the Symposium, two were devoted to calibration work at the national standardizing laboratories, two to work at SSDLs and related international activities, two to standardization and calibration in radia­ tion protection, one to standardization and calibration of radioactive sources, one to basic physical aspects, and two to absorbed dose determinations. A total of 65 papers were presented, nine of which were given by invited speakers. The 137 participants represented 26 countries and eight international organizations. The Proceedings, published in two volumes, include the papers and the sub­ sequent discussions.