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Title: Final Report: Scintillator Materials for Medical Applications, December 1, 1997 - November 30, 1999

Abstract

From the very beginning of our program we regarded the understanding of the scintillation mechanism as our primary mission. If in addition this understanding could lead to the discovery of a new material, so much the better. When we began this work some nine years ago, the theoretical basis for the scintillation phenomenon was in disarray. The initial and final steps were reasonably well characterized, but there was no consensus on the crucial intermediate, the transfer of energy from the lattice to the emitting center. In the over 40 publications that resulted from this program, we demonstrated that despite the highly insulating nature of the hosts and the great magnitude of the band gap, the primary means of transport is through mobile charge carriers and their sequential capture by the emitting center. Although radical at the time, this picture is now generally accepted throughout the field. Subsequently, we also recognized the critical role that trapping centers localized at lattice defects can play in the process, not merely as passive sources of loss but as active participants in the kinetics. In this sense shallow traps can wreak more havoc than deep ones, impeding the rate by which carriers can reach themore » emitting centers and seriously slowing the resulting decay. And we established low-temperature thermoluminescence as a comprehensive tool for quantizing these effects. As for new and better materials, our work also had an impact. We were among the first to recognize the potential of LuAlO{sub 3} (lutetium aluminum perovskite, or LuAP) as a detector for PET applications. Although this material has not supplanted LuSiO{sub 5} (lutetium oxysilicate, or LSO) in terms of light output or absence of afterglow, LuAP still exhibits by far the highest figure of merit (light output divided by decay time) of any scintillator material currently known. Our work has also bought into stark view the dismaying realization of just how improbable it is that a material will ever be found that will be capable of any more than an incremental improvement in performance.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Boston University, Boston, MA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
763152
DOE Contract Number:  
FG02-90ER61033
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 May 2000
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ALUMINIUM OXIDES; CHARGE CARRIERS; CRYSTAL DEFECTS; DECAY; KINETICS; LUTETIUM OXIDES; SCINTILLATIONS; THERMOLUMINESCENCE; SILICON OXIDES; BIOMEDICAL RADIOGRAPHY

Citation Formats

Lempicki, A., Brecher, C., Wojtowicz, A.J., and Szupryczynski, P. Final Report: Scintillator Materials for Medical Applications, December 1, 1997 - November 30, 1999. United States: N. p., 2000. Web. doi:10.2172/763152.
Lempicki, A., Brecher, C., Wojtowicz, A.J., & Szupryczynski, P. Final Report: Scintillator Materials for Medical Applications, December 1, 1997 - November 30, 1999. United States. doi:10.2172/763152.
Lempicki, A., Brecher, C., Wojtowicz, A.J., and Szupryczynski, P. Mon . "Final Report: Scintillator Materials for Medical Applications, December 1, 1997 - November 30, 1999". United States. doi:10.2172/763152. https://www.osti.gov/servlets/purl/763152.
@article{osti_763152,
title = {Final Report: Scintillator Materials for Medical Applications, December 1, 1997 - November 30, 1999},
author = {Lempicki, A. and Brecher, C. and Wojtowicz, A.J. and Szupryczynski, P.},
abstractNote = {From the very beginning of our program we regarded the understanding of the scintillation mechanism as our primary mission. If in addition this understanding could lead to the discovery of a new material, so much the better. When we began this work some nine years ago, the theoretical basis for the scintillation phenomenon was in disarray. The initial and final steps were reasonably well characterized, but there was no consensus on the crucial intermediate, the transfer of energy from the lattice to the emitting center. In the over 40 publications that resulted from this program, we demonstrated that despite the highly insulating nature of the hosts and the great magnitude of the band gap, the primary means of transport is through mobile charge carriers and their sequential capture by the emitting center. Although radical at the time, this picture is now generally accepted throughout the field. Subsequently, we also recognized the critical role that trapping centers localized at lattice defects can play in the process, not merely as passive sources of loss but as active participants in the kinetics. In this sense shallow traps can wreak more havoc than deep ones, impeding the rate by which carriers can reach the emitting centers and seriously slowing the resulting decay. And we established low-temperature thermoluminescence as a comprehensive tool for quantizing these effects. As for new and better materials, our work also had an impact. We were among the first to recognize the potential of LuAlO{sub 3} (lutetium aluminum perovskite, or LuAP) as a detector for PET applications. Although this material has not supplanted LuSiO{sub 5} (lutetium oxysilicate, or LSO) in terms of light output or absence of afterglow, LuAP still exhibits by far the highest figure of merit (light output divided by decay time) of any scintillator material currently known. Our work has also bought into stark view the dismaying realization of just how improbable it is that a material will ever be found that will be capable of any more than an incremental improvement in performance.},
doi = {10.2172/763152},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {5}
}