Chemical polishing of LSO crystals to increase light output
Chemical polishing of LSO crystals to increase light output
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LSO 晶体的化学抛光以增加光输出
DOI：
10.1109/nssmic.1999.845817
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Cherry
中科院分区：
文献类型：
--
作者：
R. Slates;A. Chatziioannou;B. Fehlberg;Taekyeung Lee;S. Cherry
反射器的表面处理对于窄矩形晶体的光收集至关重要。作者研究了比手工和机器抛光劳动强度低、成本高的化学抛光。他们使用磷酸在110/spl deg/C、150/spl deg/C和190/spl deg/C下化学抛光LSO晶体，并将这些晶体与未抛光和机械抛光的晶体进行比较。在每种温度下蚀刻五个2/spl倍/2/spl倍/10 mm晶体的组不同的时间。重量损失，光输出和能量分辨率作为处理时间和温度的函数进行测量。作者发现，化学抛光可以使光输出相对于未抛光的晶体增加250%，相对于机械抛光的晶体增加16%。能量分辨率是相对独立的表面处理，与值之间的14和16%。LSO的损失速率在110/spl deg/C下为0.03%/min，在150/spl deg/C下为0.1%/min，在190/spl deg/C下为0.36%/min。当去除5-10%的LSO时，发生最大光输出。还使用扫描电子显微镜对晶体进行成像，并通过使用轮廓仪定量评估表面粗糙度。这些测量有助于澄清酸抛光对闪烁体表面的影响。总之，化学抛光似乎是一种方便和有效的方法，以提高从小LSO晶体的光输出。
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/spl deg/C, 150/spl deg/C and 190/spl deg/C, and compared these with unpolished and mechanically polished crystals. Groups of five 2/spl times/2/spl times/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/spl deg/C, 0.1%/min at 150/spl deg/C and 0.36%/min at 190/spl deg/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.