电子辐照下的光电倍增管窗口材料：荧光和磷光

Photomultiplier window materials under electron irradiation: fluorescence and phosphorescence.

作者信息

Viehmann W, Eubanks A G, Pieper G F, Bredekamp J H

出版信息

Appl Opt. 1975 Sep 1;14(9):2104-15. doi: 10.1364/AO.14.002104.

DOI:10.1364/AO.14.002104

PMID:20154970

Abstract

The fluorescence and phosphorescence of photomultiplier window materials under electron irradiation have been investigated using a Sr(90)-Y(90) beta emitter as the electron source. Spectral emission curves of uv-grade, optical-grade, and electron-irradiated samples of MgF(2) and LiF, and of CaF(2), BaF(2), sapphire, fused silica, and uv-transmitting glasses were obtained over the 200-650-nm spectral range. Fluorescence yields, expressed as the number of counts in a solid angle of 2pi sr/MeV of incident electron energy deposited [MeV(-1) (2pi sr)(-1)], were determined on these materials utilizing photomultiplier tubes with cesium telluride, bialkali, and trialkali (S-20) photocathodes, respectively. Typical yields observed with a uv/visible sensitive bialkali cathode range from 10 MeV(-1) (2pi sr)(-1) for uv-grade MgF(2) to approximately 200 MeV(-1) (2pi sr)(-1) for CaF(2). For comparison, sodium-activated cesium iodide, one of the most efficient scintillator materials, yields about 700 MeV(-1) (2pi sr)(-1). High-purity fused silica has the lowest yield, approximately 6 MeVW(-1) (2pi sr)(-1). Optical-grade MgF(2)and LiF, as well as electron-irradiated uv-grade samples of these two materials, show enhanced fluorescence due to color-center formation and associated emission bands in the blue and red wavelength regions. Large variations in fluorescence intensities were found in uv-grade sapphire samples of different origins, particularly in the red end of the spectrum, presumably due to various amounts of chromium-ion content. Phosphorescence decay with time is best described by a sum of exponential terms, with time constants ranging from a few minutes to several days. Phosphorescence intensity expressed as a fraction of the steady-state fluorescence intensity is an extremely sensitive measure of crystalline perfection and purity. This fraction ranges from a high of approximately 10(-2) for some fluoride samples to a low of </=2 x 10(-6) for fused silica. Application of the parameters obtained in this work to the analysis of recent flight observations on low light-level experiments yields good quantitative agreement with flight data from OAO-3, OSO-7, and Apollo 17.

摘要

利用锶（90）-钇（90）β发射体作为电子源，对光电倍增管窗口材料在电子辐照下的荧光和磷光进行了研究。在200 - 650纳米光谱范围内，获得了氟化镁（MgF₂）、氟化锂（LiF）以及氟化钙（CaF₂）、氟化钡（BaF₂）、蓝宝石、熔融石英和紫外透射玻璃的紫外级、光学级和电子辐照样品的光谱发射曲线。荧光产额表示为每兆电子伏入射电子能量沉积在2π球面度立体角内的计数[兆电子伏⁻¹（2π球面度）⁻¹]，分别使用具有碲化铯、双碱和三碱（S - 20）光电阴极的光电倍增管对这些材料进行测定。使用紫外/可见敏感双碱阴极观察到的典型产额范围从紫外级MgF₂的10兆电子伏⁻¹（2π球面度）⁻¹到CaF₂的约200兆电子伏⁻¹（2π球面度）⁻¹。作为比较，钠激活碘化铯是最有效的闪烁体材料之一，其产额约为700兆电子伏⁻¹（2π球面度）⁻¹。高纯度熔融石英产额最低，约为6兆电子伏⁻¹（2π球面度）⁻¹。光学级MgF₂和LiF以及这两种材料的电子辐照紫外级样品，由于色心形成以及在蓝色和红色波长区域相关的发射带，显示出增强的荧光。在不同来源的紫外级蓝宝石样品中发现荧光强度有很大变化，特别是在光谱的红色端，推测是由于铬离子含量不同。磷光随时间的衰减最好用指数项之和来描述，时间常数范围从几分钟到几天。磷光强度表示为稳态荧光强度的分数，是晶体完美度和纯度的极其敏感的度量。该分数范围从一些氟化物样品的约10⁻²的高值到熔融石英的≤2×10⁻⁶的低值。将这项工作中获得的参数应用于对近期低光水平实验飞行观测的分析，与轨道天文台3号（OAO - 3）、轨道太阳观测站7号（OSO - 7）和阿波罗17号的飞行数据在定量上有良好的一致性。