EDUARDO G. YUKIHARA | STEPHEN W. S. McKEEVER Optically Stimulated Luminescence FUNDAMENTALS AND APPLICATIONS Optically Stimulated Luminescence Optically Stimulated Luminescence Fundamentals and Applications EDUARDO G. YUKIHARA and STEPHEN W. S. McKEEVER Physics Department, Oklahoma State University Oklahoma, USA A John Wiley and Sons, Ltd., Publicatio n This edition first published 2011 C 2011 John Wiley & Sons Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com. The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. 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No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom. Library of Congress Cataloging-in-Publication Data Yukihara, Eduardo G. Optically stimulated luminescence : fundamentals and applications / Eduardo G. Yukihara and Stephen W.S. McKeever. p. cm. Includes bibliographical references and index. ISBN 978-0-470-69725-2 (cloth) – ISBN 978-0-470-97705-7 (ePDF) – ISBN 978-0-470-97706-4 (ebook) 1. Optically stimulated luminescence dating. 2. Radiation dosimetry. I. McKeever, S. W. S., 1950– II. Title. QE508.Y85 2011 535 .356–dc22 2010037269 A catalogue record for this book is available from the British Library. Print ISBN: 978-0-470-69725-2 ePDF ISBN: 978-0-470-97705-7 oBook ISBN: 978-0-470-97706-4 ePub ISBN: 978-0-470-97721-7 Typeset in 10/12pt Times by Aptara Inc., New Delhi, India. Printed and bound in Singapore by Markono Print Media Pte Ltd. To Stefanie, my music, my silence To Joan and our wonderful daughters, Katie and Alison. Contents Preface xi Acknowledgments xiii Disclaimer xiv List of Acronyms xv 1 Introduction 1 1.1 A Short History of Optically Stimulated Luminescence 1 1.2 Brief Description of Successful Applications 7 1.2.1 Personal 7 1.2.2 Space 8 1.2.3 Medical 9 1.2.4 Security 10 1.3 The Future 10 2 Theory and Practical Aspects 13 2.1 Introduction 13 2.2 Basic Aspects of the OSL Phenomenon 17 2.2.1 Energy Levels in Perfect Crystals 17 2.2.2 Defects in the Crystal 18 2.2.3 Excitation of the Crystal by Ionizing Radiation 19 2.2.4 Trapping and Recombination at Defect Levels 22 2.2.5 Thermal Stimulation of Trapped Charges 24 2.2.6 Optical Stimulation of Trapped Charges 25 2.2.7 The Luminescence Process 27 2.2.8 Rate Equations for OSL and TL Processes 33 2.2.9 Temperature Dependence of the OSL Signal 40 2.2.10 Other OSL Models 44 2.3 OSL Readout 47 2.3.1 Basic Elements of an OSL Reader 47 2.3.2 Stimulation Modalities 48 2.4 Instrumentation 58 2.4.1 Light Sources 59 2.4.2 Light Detectors 63 2.4.3 Optical Filters 67 2.4.4 Light Collection 69 2.4.5 Sample Heaters 69 viii Contents 2.5 Available OSL Readers 70 2.5.1 Experimental Arrangements 70 2.5.2 Automated Research Readers 71 2.5.3 Commercial Dosimetry Readers 73 2.5.4 Optical Fiber Systems 74 2.5.5 Imaging Systems 75 2.5.6 Portable OSL Readers 76 2.6 Complementary Techniques 76 2.6.1 OSL Emission and Stimulation Spectrum 76 2.6.2 Lifetime and Time-Resolved OSL Measurements 78 2.6.3 Correlations Between OSL and TL 78 2.6.4 Other Phenomena 82 2.7 Overview of OSL Materials 82 2.7.1 Artificial Materials 85 2.7.2 Natural Materials 95 2.7.3 Electronic Components 98 2.7.4 Other OSL Materials and Material Needs 98 3 Personal Dosimetry 101 3.1 Introduction 101 3.2 Quantities of Interest 102 3.2.1 Absorbed Dose and Other Physical Quantities 103 3.2.2 Protection Quantities 108 3.2.3 Operational Quantities 110 3.3 Dosimetry Considerations 111 3.3.1 Definitions 111 3.3.2 Dose Calculation Algorithm 114 3.3.3 Reference Calibration Fields for Personal and Area Dosimeters 118 3.3.4 Uncertainty Analysis and Expression of Uncertainty 119 3.4 Detectors 123 3.4.1 General Characteristics 123 3.4.2 Al 2 O 3 :C Detectors 129 3.4.3 BeO Detectors 140 3.5 Dosimetry Systems 143 3.5.1 Luxel+Dosimetry System 143 3.5.2 InLight Dosimetry System 146 3.6 Neutron-Sensitive OSL Detectors 150 3.6.1 Development of Neutron-Sensitive OSL Detectors 151 3.6.2 Properties of OSLN Detectors 154 3.6.3 Ionization Density Effects 157 4 Space Dosimetry 163 4.1 Introduction 163 4.2 Space Radiation Environment 165 4.2.1 Galactic Cosmic Rays (GCR) 165 4.2.2 Earth’s Radiation Belts (ERB) 167 [...]... detector pulsed optically stimulated luminescence relative biological effectiveness radioluminescence spread out Bragg peak solar particle event thermoluminescence/thermally stimulated luminescence ultraviolet World Health Organization yttrium aluminum garnet (Y3 Al5 O12 ) 1 ‘OSLD’ has been used in the literature for optically stimulated luminescence dosimeter’ and optically stimulated luminescence. .. intensity modulated proton therapy infrared infrared stimulated luminescence International Organization for Standardization International Space Station light emitting diode linear energy transfer linear modulation optically stimulated luminescence National Council on Radiation Protection and Measurements optically stimulated luminescence/ photostimulated luminescence xvi List of Acronyms OSLD/TLD OTOR PMT... elements of 4 Optically Stimulated Luminescence the phenomenon that we now term optically stimulated luminescence Namely, after irradiation with the primary ionizing source, energy may be stored in the material in the form of trapped charge carriers (electrons and holes) Release of the trapped charge can then be stimulated by the absorption of optical photons of appropriate wavelength, resulting in luminescence. .. author(s), for what is now known as optically stimulated luminescence Description of the Phenomenon Name of the Phenomenon Author, and Date of First Introduction Light stimulated transfer of electrons from deep traps to shallow traps followed by phosphorescence Photophosphorescence Unidentifieda (1889) Delayed optically stimulated luminescence Yoder and Salasky (1997) Light stimulated release of electrons... stable concentration of trapped Optically Stimulated Luminescence: Fundamentals and Applications © 2011 John Wiley & Sons, Ltd Eduardo G Yukihara and Stephen W S McKeever 14 Optically Stimulated Luminescence (a) Excitation (b) Latency Exposure to ionizing radiation (e.g., X-rays, γ-rays) OSL detector (c) Stimulation Exposure to stimulation light (e.g., green light) Stimulated luminescence (e.g., blue emission)... photostimulated luminescence (PSL) The sensitivity and speed of readout of the stimulated luminescence signal has given radiologists the ability to reduce radiation doses to patients and yet provide high-resolution images to aid diagnosis However, the use of OSL in this way is not dosimetry The actual dose to the patient is still determined by conventional OSL (or TL) methods 10 Optically Stimulated Luminescence. .. ionizing radiation, from X-rays, an electron beam or a radioactive substance Optically stimulated luminescence (OSL) is a related phenomenon in which the luminescence is stimulated by the absorption of optical energy, rather than thermal energy It is difficult to identify when studies of OSL (or, as it is also known, photostimulated luminescence, PSL) were first described in the literature However, certainly... the words optically stimulated luminescence between 2000 and 2009 reveals 22 270 articles A search without date restriction shows 25 200 articles Perhaps of even more interest is the growth in the number of such articles over the past two decades, as shown in Figure 1.2 Finally we may note that a word search on Google finds about 2 850 000 entries containing the phrase optically stimulated luminescence ... phosphorescence, which is the afterglow emitted from a substance after the absorption of external energy (See Harvey (1957) for a Optically Stimulated Luminescence: Fundamentals and Applications © 2011 John Wiley & Sons, Ltd Eduardo G Yukihara and Stephen W S McKeever 2 Optically Stimulated Luminescence comprehensive review of the early literature on this topic A more modern discussion of TL and its relationship... Physicists in Medicine as low as reasonably achievable charge-coupled device charged particle equilibrium computed tomography computed tomography dose index continuous wave optically stimulated luminescence delayed optically stimulated luminescence electron paramagnetic resonance Earth’s radiation belts European Society for Therapeutic Radiology and Oncology galactic cosmic rays heavy charged particle . modulation optically stimulated luminescence NCRP National Council on Radiation Protection and Measurements OSL/PSL optically stimulated luminescence/ photostimulated. for optically stimulated luminescence dosimeter’ and optically stimulated luminescence detector’ indiscriminately. In this book we used OSLD for ‘optically