Development of New Types of Linear Photo Detectors

我们搭建了一套测试装置，测量线性度的精度为0.1%。通过使用该系统，我们评估了下列新型光电探测器的线性度。*雪崩型光电二极管在雪崩光电二极管上施加大约1500V-2400V的偏置电压。进入p型硅的光子形成电子-空穴对。电子被电压加速，并产生另一对电子，从而放大信号。在14万个入射光子的情况下，增益为200的非线性小于0.1%。*硅二极管混合型光电倍增管该探测器由阴极和PIN二极管组成，它们之间的电压约为10KV。来自阴极的光电子被加速，当它们击中二极管时，每个光电子产生大约2500个电子。该信号由PIN二极管检测。由于简单的电子轨迹和PIN二极管良好的线性度，该探测器具有良好的线性度。在14万个入射光子的情况下，测量的非线性小于0.1%。*雪崩型硅二极管混合型光电倍增管该探测器与上面的探测器相同，只是它使用了雪崩二极管而不是PIN二极管，以获得更高的增益。对于14000个入射光子，在增益为5000的情况下，测量到的非线性约为6%。这种大的非线性是由于雪崩光电二极管本身，原则上它应该是更线性的更好的雪崩光电二极管。

We have built a test setup to measure the linearity with the precision of 0.1%. By using the system, we have evaluated the linearity of the following new types of photo detectors.*Avalanche type photo diodeA bias voltage of about 1500V-2400V is applied on an avalanche photo diode (APD). A photon entering the p-type silicon forms an electron-hole pair. The electron is accelerated by the voltage, and produce another pairs, thereby amplifies the signal. The nonlinearity at the gain of 200 was less than 0.1% up to 140 thousand incident photons.*Hybrid type photomultiplier with Si diodeThis detector consists of cathode and PIN diode, and a voltage of about 10kV is applied between them. Photoelectrons from the cathode is accelerated, and produce about 2500 electorons per photoelectron when they hit the diode. The signal is detected by the PIN diode. This detector has an excellent linearity because of simple electron trajectory, and the good linearity of the PIN diode. The measured non-linearity was less than 0.1% up to 140 thousand incident photons.*Hybrid type photomultiplier with avalanche type Si diodeThis detector is same as the above except that it uses APD instead of PIN diode, to obtain higher gain. The measured non-linearity was about 6% at the gain of 5000, for 14 thousand incident photons. This large non-linearity was due to the avalanche photo diode itself, and it should in principle be more linear with a better APD.