Evaluation of a reflective coating for an organic scintillation detector

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• 作者：A. Tarancó ; n^a ; ^{alex.tarancon@ub.edu} ; E. Marin^a ; J. Tent^b ; G. Rauret^a ; J.F. Garcia^a
• 关键词：Plastic scintillation ; Reflective coating ; White paint ; Custom-made detector
• 刊名：Nuclear Instruments and Methods in Physics Research Section A ; Accelerators ; Spectrometers ; Detectors and Associated Equipment
• 出版年：2012
• 期刊代码：41_01689002
• 类别：ph
• 出版时间：11 May, 2012
• 卷：674
• 期：Complete
• 页码：92-98
• 文件大小：740 K

摘要

A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO₂, were also tested to determine the one with the best performance and lowest radioactivity content.

In a first experiment, we evaluated the capability of the reflective coating by measuring ⁹⁰Sr/⁹⁰Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt).

The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides (⁴⁰K, ²²⁶Ra and ²²⁸Ra) in the EJ510.

On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).