Development of New Types of Linear Photo Detectors

我们已经建立了一个测试装置来测量线性度，精度为0.1%。通过使用该系统，我们评估了以下新型光电探测器的线性度。雪崩型光电二极管雪崩光电二极管（APD）上施加约1500 V-2400 V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，并产生另一对电子对，从而放大信号。增益为200时，入射光子数高达14万时，非线性度小于0.1%。*硅二极管混合型光电倍增管这种探测器由阴极和PIN二极管组成，阴极和PIN二极管之间施加约10 kV的电压。来自阴极的光电子被加速，并且当它们撞击二极管时，每个光电子产生大约2500个电子。信号由PIN二极管检测。由于电子轨迹简单，加上PIN二极管的良好线性，该探测器具有良好的线性度。测量的非线性度小于0.1%，直到14万个入射光子。混合型光电倍增管与雪崩型硅二极管这种探测器与上述相同，除了它使用APD代替PIN二极管，以获得更高的增益。在增益为5000时，对于14000个入射光子，测得的非线性约为6%。这种大的非线性是由于雪崩光电二极管本身，并且原则上它应该与更好的APD更线性。

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.