Radiological Safety Aspects of the Operation of Proton Accelerators

490 Pages·2011·19.54 MB·English

TECHNICAL REPORTS SERIES IMo. 2 83
Radiological Safety Aspects
of the Operation
of Proton Accelerators
^ INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1988
LVJ
The cover picture shows part of the first cyclotron.
By courtesy of Lawrence Berkeley Laboratory, University of California.
RADIOLOGICAL SAFETY ASPECTS
OF THE OPERATION
OF PROTON ACCELERATORS
The following States are Members of the International Atomic Energy Agency:
AFGHANISTAN GUATEMALA PARAGUAY
ALBANIA HAITI PERU
ALGERIA HOLY SEE PHILIPPINES
ARGENTINA HUNGARY POLAND
AUSTRALIA ICELAND PORTUGAL
AUSTRIA INDIA QATAR
BANGLADESH INDONESIA ROMANIA
BELGIUM IRAN, ISLAMIC REPUBLIC OF SAUDI ARABIA
BOLIVIA IRAQ SENEGAL
BRAZIL IRELAND SIERRA LEONE
BULGARIA ISRAEL SINGAPORE
BURMA ITALY SOUTH AFRICA
BYELORUSSIAN SOVIET JAMAICA SPAIN
SOCIALIST REPUBLIC JAPAN SRI LANKA
CAMEROON JORDAN SUDAN
CANADA KENYA SWEDEN
CHILE KOREA, REPUBLIC OF SWITZERLAND
CHINA KUWAIT SYRIAN ARAB REPUBLIC
COLOMBIA LEBANON THAILAND
COSTA RICA LIBERIA TUNISIA
COTE D'lVOIRE LIBYAN ARAB JAMAHIRIYA TURKEY
CUBA LIECHTENSTEIN UGANDA
CYPRUS LUXEMBOURG UKRAINIAN SOVIET SOCIALIST
CZECHOSLOVAKIA MADAGASCAR REPUBLIC
DEMOCRATIC KAMPUCHEA MALAYSIA UNION OF SOVIET SOCIALIST
DEMOCRATIC PEOPLE'S MALI REPUBLICS
REPUBLIC OF KOREA MAURITIUS UNITED ARAB EMIRATES
DENMARK MEXICO UNITED KINGDOM OF GREAT
DOMINICAN REPUBLIC MONACO BRITAIN AND NORTHERN
ECUADOR MONGOLIA IRELAND
EGYPT MOROCCO UNITED REPUBLIC OF
EL SALVADOR NAMIBIA TANZANIA
ETHIOPIA NETHERLANDS UNITED STATES OF AMERICA
FINLAND NEW ZEALAND URUGUAY
FRANCE NICARAGUA VENEZUELA
GABON NIGER VIET NAM
GERMAN DEMOCRATIC REPUBLIC NIGERIA YUGOSLAVIA
GERMANY, FEDERAL REPUBLIC OF NORWAY ZAIRE
GHANA PAKISTAN ZAMBIA
GREECE PANAMA ZIMBABWE
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 Head-
quarters 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".
© IAEA, 1988
Permission to reproduce or translate the information contained in this publication may be
obtained by writing to the International Atomic Energy Agency, Wagramerstrasse 5, P.O. Box 100,
A-1400 Vienna, Austria.
Printed by the IAEA in Austria
May 1988
TECHNICAL REPORTS SERIES No. 283
RADIOLOGICAL SAFETY ASPECTS
OF THE OPERATION
OF PROTON ACCELERATORS
A report written by
Ralph H. THOMAS
Lawrence Berkeley Laboratory
University of California
United States of America
and
Graham R. STEVENSON
European Centre for Nuclear Research
(CERN)
INTERNATIONAL ATOMIC ENERGY AGENCY
VIENNA, 1988
RADIOLOGICAL SAFETY ASPECTS
OF THE OPERATION OF PROTON ACCELERATORS
IAEA, VIENNA, 1988
STI/DOC/10/283
ISBN 92-0-125188-2
FOREWORD
Particle accelerators are finding increased application in both the fundamental
and applied sciences and in industry around the world. Recognizing this, the
International Atomic Energy Agency began, in 1975, preparing a series of technical
reports dealing with the radiological safety of accelerator operation. The first of
these, IAEA Safety Series No. 42, entitled Radiological Safety Aspects of the Opera-
tion of Neutron Generators and written by R.F. Boggs, was published in 1976. A
second book, Radiological Safety Aspects of the Operation of Electron Linear
Accelerators (IAEA Technical Reports Series No. 188), written by W.P. Swanson,
was issued in 1979. This present report deals with positive ion accelerators.
Since their first operation in the 1930s, positive ion accelerators have been
applied to a wide range of investigations in the fundamental sciences, including
astronomy, biology, chemistry and physics. Indeed, the birth of the 'radiation
sciences' — nuclear physics, fundamental particle physics, radiation biology and
radiation chemistry — largely derives from the creation of positive ion accelerators.
While the use of these accelerators in the applied sciences and industry has perhaps
been slower, and is less extensive, than has been the case for electron accelerators,
it is now rapidly increasing. Positive ion accelerators are being applied in a host of
fields, including radiation damage studies, induced activation and dating
measurements, radiography, radiotherapy and fusion research. Because these
devices can be potent sources of neutrons, it is important that information concerning
their safe operation be widely available.
This report is conceived as a source book providing authoritative guidance in
radiation protection from an important category of radiation sources. It thus
supplements other manuals of the IAEA related to the planning and implementation
of radiation protection programmes. The authors, Ralph H. Thomas of the
University of California and Graham R. Stevenson of the European Organization for
Nuclear Research (CERN), were engaged as consultants by the Agency to compile
and write the report, and the Agency wishes to express its gratitude to them.
Comments from readers for possible inclusion in a later edition of the manual
are welcome and should be addressed to:
The Director,
Division of Nuclear Safety,
International Atomic Energy Agency,
Wagramerstrasse 5, P.O. Box 100,
A-1400 Vienna,
Austria.

CONTENTS
INTRODUCTION 1
CHAPTER 1. CHARACTERISTICS OF POSITIVE ION
ACCELERATORS 7
1.1. Historical review 7
1.1.1. Phases of accelerator development 8
1.2. Types of positive ion accelerators 14
1.3. Physical and radiological characteristics of positive ion accelerators .. 14
1.3.1. Particle energy 14
1.3.2. Beam intensity 16
1.3.3. Number of accelerators 18
1.4. Fields of application 19
1.5. Typical installations 21
1.5.1. 30 MV electrostatic generator — Daresbury Laboratory 22
1.5.2. 800 MeV linear accelerator — Clinton P. Anderson Meson
Physics Facility 28
1.5.3. 800 MeV proton synchrotron: spallation neutron source —
Rutherford Appleton Laboratory 34
1.5.4. Multi-GeV heavy ion facility: Bevalac —
Lawrence Berkeley Laboratory 38
1.5.5. 12 GeV strong focusing proton synchrotron (KEK) —
National Laboratory for High Energy Physics 41
L5.6. The CERN Super Proton Synchrotron (SPS) 48
References to Chapter 1 55
CHAPTER 2. RADIATION ENVIRONMENT OF POSITIVE ION
ACCELERATORS 63
2.1. Introduction 63
2.2. Prompt radiation fields 65
2.2.1. Historical background 65
2.2.2. Operational experience at high energy accelerators 67
2.2.3. Typical neutron spectra at proton accelerators 68
2.2.4. Charged particle environment outside high energy proton
accelerator shields 73
2.2.5. Heavy ion accelerators 80
2.2.6. Interpretation of accelerator radiation measurements 82
2.3. Induced radioactivity 90
2.3.1. Introduction: the remanent radiation field 90
2.3.2. Characteristics of the remanent radiation field 91
2.3.3. Magnitude of the problem of induced radioactivity 93
2.3.4. Induced radioactivity 95
2.3.5. Handling and maintenance of radioactive accelerator
components 112
2.3.6. Disposal of radioactive accelerator components 113
References to Chapter 2 124
CHAPTER 3. RADIATION MEASUREMENTS AT ACCELERATORS .. 137
3.1. Dosimetry at particle accelerators 137
3.2. Historical background 140
3.3. Mixed radiation field dosimetry 143
3.3.1. Ionization chambers 143
3.3.2. LET spectrometer instruments 144
3.3.3. Other dose equivalent or radiation quality instruments 145
3.4. Neutron dosimetry at accelerators 146
3.4.1. Classification of radiation detectors 146
3.4.2. Passive detectors 146
3.4.3. Active (prompt) detectors 147
3.4.4. Threshold detectors 147
3.4.5. Activation detectors 148
3.4.6. Moderated thermal neutron detectors 158
3.4.7. Multisphere techniques 161
3.5. Radiation surveys 162
3.5.1. Single detector 163
3.5.2. Two detectors 163
3.5.3. Three or more detectors 164
3.6. Dose equivalent instruments versus physical measurements 168
3.7. Determination of neutron spectra at accelerators 170
3.8. Interpretation of accelerator radiation measurements 173
3.8.1. Fluence to dose equivalent conversion coefficients ; 173
3.8.2. Intercomparison of dose equivalent determinations 178
References to Chapter 3 182