Devolopment of Amplified GaAs Imager

我们研制了APD型、EB型(电子轰击型)和注入型成像器件，这些器件都是用砷化镓单晶薄膜制成的。稀释法是通过抛光技术完成的。我们用一个安装在蒸发器上的可拆卸装置来测量摄像。我们使用了低速光束扫描系统，也使用了高速光束扫描系统来获得精确的滞后特性。APD型和EB型的分辨率极限大于550TVL，APD型和EB型的滞后为零。雪崩光电倍增10时的过量噪声系数为1，而雪崩光电倍增为100时的过剩噪声因子为10，几乎所有数据都与a-se的数据相似。由于弱负滞后的存在，可能存在基于偶极子模型的降噪效应。EB增益在100~1000之间时，EB型的超额噪声系数为1.2。注入型的暗电流很大，我们无法测量过多的噪声因子。用砷化镓制作的雪崩光电二极管的热阻比a-Se制作的雪崩光电二极管的热阻大，工作电压是a-Se雪崩光电二极管工作电压的十分之一，这些特点改善了它的重复性，为电子束和雪崩光电二极管混合模式的超高灵敏度成像器提供了条件。

We developed the image devices of APD type, EB type (Electron Bombardmet type) and injection type, which were made of GaAs single crystalline film. The thinning method was done by a polishing technique. We measured the pickup images by a demountable apparatus attached to an evaporator. We used a low velocity beam scanning system, and also used high velocity beam scanning system for precise lag characteristics. The resolution limits of the APD and EB type are more than 550 TVL.The lags of APD type and EB type are zero. The excess noise factor of APD gain of ten is unity, whereas the one of APD gain of 100 is 10, almost all data are like those of a-Se. There may be the noise reduction effect based on dipole model in a-Se because of the presence of a weak negative lag. The excess noise factor of EB type is 1.2 for EB gain from 100 to 1000. The dark current of an injection type is enormous, we cannot measured the excess noise factor. The heat resistance APD made by GaAs is lager than that of APD made by a-Se, the working voltage is tenth of the voltage of a-Se APD.These features improve the reproducibility, they serve a super high sensitive imager of mixed mode of EB and APD.