# An novel analog programmable power supply for active gain control of the Multi-Pixel Photon Counter (MPPC) [IMA]

Silicon Photo-Multipliers (SiPM) are regarded as novel photo-detector to replace conventional Photo-Multiplier Tubes (PMTs). However, the breakdown voltage dependence on the ambient temperature results in a gain variation of $\sim$3$\% /^{\circ} \mathrm C$. This can severely limit the application of this device in experiments with wide range of operating temperature, especially in space telescope. An experimental setup in dark condition was established to investigate the temperature and bias voltage dependence of gain for the Multi-Pixel Photon Counter (MPPC), one type of the SiPM developed by Hamamatsu. The gain and breakdown voltage dependence on operating temperature of an MPPC can be approximated by a linear function, which is similar to the behavior of a zener diode. The measured temperature coefficient of the breakdown voltage is $(59.4 \pm 0.4$ mV)$/^{\circ} \mathrm C$. According to this fact, a programmable power supply based on two zener diodes and an operational amplifier was designed with a positive temperature coefficient. The measured temperature dependence for the designed power supply is between 63.65 to 64.61mV/$^{\circ} \mathrm C$ at different output voltages. The designed power supply can bias the MPPC at a over-voltage with a variation of $\sim$ 5mV$/^{\circ} \mathrm C$. The gain variation of the MPPC biased at over-voltage of 2V was reduced from 2.8$\% /^{\circ} \mathrm C$ to 0.3$\% /^{\circ} \mathrm C$. Detailed design and performance of the programmable power supply in the temperature range from -42.7$^{\circ}\mathrm{C}$ to 20.9$^{\circ}\mathrm{C}$ will be discussed in this paper.

Z. Li, C. Liu, Y. Xu, et. al.
Tue, 14 Jun 16
29/67