# Radiation tolerance of FPCCD vertex detector for the ILC

## TL;DR

This paper evaluates the radiation tolerance of FPCCD sensors for the ILC vertex detector by measuring charge transfer inefficiency after neutron irradiation and exploring methods to mitigate damage.

## Contribution

It presents the measurement of CTI degradation in irradiated FPCCD prototypes and investigates fat-zero charge injection as a method to improve CTI after radiation damage.

## Key findings

- Neutron irradiation degrades CTI in FPCCD sensors.
- Fat-zero charge injection partially restores CTI in irradiated FPCCDs.
- The study advances understanding of radiation effects on vertex detector sensors.

## Abstract

The Fine Pixel CCD (FPCCD) is one of the candidate sensor technologies for the ILC vertex detector. The vertex detector is located near the interaction point, thus high radiation tolerance is required. Charge transfer efficiency of CCD is degraded by radiation damage which makes traps in pixels. We measured charge transfer inefficiency (CTI) of a neutron irradiated FPCCD prototype. We observed a degradation of CTI compared with non-irradiated CCD. To improve the CTI of irradiated CCD, we performed the fat-zero charge injection to fill the traps. In this paper, we report a status of CTI improvement.