The investigation and comparison of three photodiode-based candidate structures for detecting the X-ray

Abstract

Recently, research has shown that PIN photodiodes can be used in ionization radiation detection, especially in medical applications. In this research, three photodiode-based X-ray detectors have been implemented. The preamplifiers in these circuits have completely different structures; the number of pulse shaper stages and the bias of photodiodes are different. The first circuit benefits lower manufacturing costs due to its simple structure. The second circuit has a preamplifier with feedback impedance that generates pulses with a large amplitude. The third circuit has better noise than the second circuit due to the transistor preamplifier structure with a small feedback capacitor, and its gain is larger than the first circuit. The S1223-01 photodiode from Hamamatsu Corporation has been utilized in the experiments, which is excited using the 232Th. Comparing the conversion gain, dissipation power, and pulse period of these circuits, the second circuit with a gain of 66.75-dB can be claimed to have the largest amplitude. Also, the first circuit with a noise power of 1.215-nV2 and a dissipation power of 36.6-mW, has recorded the lowest noise and energy consumption among others. The third circuit with a time period of 8.2-μs has the lowest pulse duration and dead time.

Keywords

• ionization radiation detection
• x ray
• photodiode
• pulse mode