Proton Radiation Damage Experiment on P-Channel CCD for an X-ray CCD camera onboard the Astro-H satellite

TL;DR

This study evaluates the radiation tolerance of a newly developed P-channel CCD for space X-ray imaging, demonstrating its robustness after proton exposure and effectiveness of charge-injection and cooling techniques.

Contribution

It provides the first proton radiation damage assessment of a P-channel CCD designed for space X-ray applications, confirming its suitability for satellite use.

Findings

The P-channel CCD remains radiation tolerant after exposure to 10^9 protons/cm^2.

Charge-injection and lower temperature reduce charge transfer inefficiency.

The device's radiation tolerance exceeds that of previous CCDs used in space.

Abstract

We report on a proton radiation damage experiment on P-channel CCD newly developed for an X-ray CCD camera onboard the Astro-H satellite. The device was exposed up to 10^9 protons cm^{-2} at 6.7 MeV. The charge transfer inefficiency (CTI) was measured as a function of radiation dose. In comparison with the CTI currently measured in the CCD camera onboard the Suzaku satellite for 6 years, we confirmed that the new type of P-channel CCD is radiation tolerant enough for space use. We also confirmed that a charge-injection technique and lowering the operating temperature efficiently work to reduce the CTI for our device. A comparison with other P-channel CCD experiments is also discussed.