Study of the basic performance of the XRPIX for the future astronomical X-ray satellite

TL;DR

This study evaluates the basic performance of XRPIX CMOS sensors for future X-ray astronomy, focusing on temperature effects on noise, gain, and energy resolution to guide improvements.

Contribution

It provides detailed analysis of temperature dependence on XRPIX performance, highlighting noise sources and informing future sensor enhancements.

Findings

Readout noise and energy resolution depend on temperature.

Electronic circuit noise is proportional to the square root of temperature.

Leak current and noise increase at higher operating temperatures.

Abstract

We have developed CMOS imaging sensor (XRPIX) using SOI (Silicon-On-Insulator) technology for the X-ray astronomical use. XRPIX(X-Ray soiPIXel) has advantage of a high time resolution, a high position resolution and an observation in a wide X-ray energy band with a thick depletion layer of over 200um. However, the energy resolution of XRPIX is not as good as one of X-ray CCD. Therefore improvement of the the energy resolution is one of the most important development item of XRPIX. In order to evaluate the performance XRPIX more precisely, we have investigated on the temperature dependence of the basic performance, such as readout noise, leak current, gain and energy resolution, using two type of XRPIX, XRPIX1 and XRPIX2b_CZ. In our study, we confirmed the readout noise, the leak current noise and the energy resolution clearly depended on the operating temperature of XRPIX. In addition, we divided the readout noise into the leak current noise and the circuit origin noise. As a result, we found that noise of the electronic circuitry origin was proportional to the square root of operating temperature.