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本文扼要分析了影响X线影像增强管增益的各种因素。结合15XZ3B管的增益问题,提出一种以测量X线激发背照射光电流I_b和“亮度—背照射光电流”特性(即L—I_b特性)为基础的分析方法。测量分析表明,15XZ3B管亮度低的原因有二个。一是输出屏“铯化”而降低了发光效率。二是光阴极膜过厚,阻碍了部分光电子的逸出,致使光阴极量子效率低下。通过在管内安装机械防铯装置、改进制屏工艺以及调整光阴极制造规范等措施,克服了“铯化”,改善了输出屏效率。另一方面,通过控制锑球重量,改进锑源结构制成薄而均匀的光阴极膜,从而提高了光阴极的量子效率。全面实现上述措施后,整管的平均亮度增加了七、八倍。“亮度”(或增益)单项参数的合格率由不到10％上升到80％,达到令人满意的效果。
This article briefly analyzes the various factors that affect the gain of X-ray image intensifier tubes. Combining with the gain problem of 15XZ3B tube, an analytical method based on the measurement of X-ray excitation backscattering current I_b and “brightness-backlit photocurrent” (ie L-I_b characteristic) is proposed. Measurement and analysis shows that 15XZ3B tube brightness is low for two reasons. First, the output screen “cesium” and reduce the luminous efficiency. Second, the light cathode film is too thick, hindering the escape of some photoelectrons, resulting in low quantum efficiency of the light and the cathode. Through the installation of mechanical anti-cesium tube in the pipe to improve the screen-making process and adjust the manufacturing standards and other measures to overcome the “cesium” to improve the output screen efficiency. On the other hand, by controlling the weight of antimony ball and improving the structure of antimony source, a thin and uniform photocathode is formed, which increases the quantum efficiency of photocathode. The full realization of the above measures, the average brightness of the whole pipe increased seven or eight times. The “pass” (or gain) of single parameter pass rate from less than 10% to 80%, to achieve satisfactory results.