DocumentCode :
2052482
Title :
Chemical polishing of LSO crystals to increase light output
Author :
Slates, Randal ; Chatziioannou, Arion ; Fehlberg, Brianna ; Lee, Taekyeung ; Cherry, Simon
Author_Institution :
Crump Inst. for Biol. Imaging, California Univ., Los Angeles, CA, USA
Volume :
2
fYear :
1999
fDate :
1999
Firstpage :
939
Abstract :
Surface treatment of scintillators is critical for light collection from narrow rectangular crystals. The authors investigated chemical polishing which is less labor intensive and costly than hand and machine polishing. They used phosphoric acid to chemically polish LSO crystals at 110°C, 150°C and 190°C, and compared these with unpolished and mechanically polished crystals. Groups of five 2×2×10 mm crystals were etched for different times at each temperature. Weight loss, light output and energy resolution were measured as a function of treatment time and temperature. The authors found that chemical polishing can increase light output by 250% relative to unpolished crystals and by 16% relative to mechanically polished crystals. The energy resolution was relatively independent of surface treatment, with values of between 14 and 16%. The rate of loss of LSO was 0.03%/min at 110°C, 0.1%/min at 150°C and 0.36%/min at 190°C. Maximum light output occurred when 5-10% of the LSO was removed. The crystals were also imaged using a scanning electron microscope and the surface roughness quantitatively assessed by using a profilometer. These measurements helped to clarify the effect of acid polishing on the surface of the scintillator. In summary, chemical polishing appears to be a convenient and effective method for improving light output from small LSO crystals
Keywords :
biomedical equipment; gamma-ray detection; polishing; positron emission tomography; radioisotope imaging; solid scintillation detectors; 110 to 190 C; LSO crystals; acid polishing; chemical polishing; energy resolution; light output increase; medical diagnostic imaging; medical instrumentation; narrow rectangular crystals; nuclear medicine; profilometer; scanning electron microscopy; scintillators surface treatment; surface roughness; weight loss; Chemicals; Crystals; Energy measurement; Energy resolution; Etching; Loss measurement; Rough surfaces; Surface roughness; Surface treatment; Temperature;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Nuclear Science Symposium, 1999. Conference Record. 1999 IEEE
Conference_Location :
Seattle, WA
ISSN :
1082-3654
Print_ISBN :
0-7803-5696-9
Type :
conf
DOI :
10.1109/NSSMIC.1999.845817
Filename :
845817
Link To Document :
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