Study on the radiation detector using new semiconductor materials.

硅半导体探测器在目前，甚至在未来的高能物理实验中，作为顶点探测器都扮演着不可或缺的角色。然而，这种探测器的物理尺寸被限制在小尺寸，因为硅晶体非常昂贵。为了制造更便宜更大的探测器，人们正在研究利用有机半导体作为辐射探测器的可能性。研究了以有机半导体为传感器的新型辐射探测器。放大器连接到有机半导体传感器。当激光注入传感器时，利用NIM和CAMAC在线数据采集系统，通过ADC和Flash ADC对输出信号进行测量。通过对实验数据的分析，我们得到了脉冲高度、S/N比和响应时间(信号上升时间)与偏置电压的关系。对于电极间距为5 mm的聚噻吩型传感器，脉冲高度和S/N比在300V以上呈现平台；对于偏置电压沿薄膜厚度(几十微米)供电的聚苯胺型传感器，在300V以上没有出现平台。聚噻吩型传感器和聚苯胺型传感器的信号上升沿时间分别约为10us和小于100 ns。从我们的研究结果来看，我们认为最适合用作辐射传感器的有机半导体是聚噻吩型和聚苯胺型。

The silicon semiconductor detector plays an indispensable role as the vertex detector at current and possibly also in future high energy physics experiments. However, the physical dimensions of such detectors are limited to small sizes because the silicon crystal is very expensive. In order to make cheaper and larger detectors, the possibility of utilizing the organic semiconductor as a radiation detector is being investigated.A study of new radiation detectors using organic semiconductors as sensors has been made. An amplifier is connected to an organic semiconductor sensor. When laser light is injected to the sensor, an output signal was measured with ADC and Flash ADC by using a NIM and CAMAC online data acquisition system. By analysis of the experimental data, we could obtain bias voltage dependence of pulse height, S/N ratio, and response time (rise time of the signal). Pulse height and S/N ratio showed plateau above 300V for the polythiophene sensor having an electrode gap of 5 mm.For the polyaniline sensor, for which the bias voltage was fed across the film thickness (several tens of microns), no plateau appeared up to 300V. Signal rise times are about 10 us and less than 100 ns for the polythiophene sensor and the polyaniline sensor, respectively.Judging from the result of our study, we think that the best organic semiconductors suitable to be used as radiation sensors are polythiophene and polyaniline.