A setup for soft proton irradiation of X-ray detectors for future astronomical space missions

TL;DR

This paper describes a specialized setup for irradiating X-ray detectors with soft protons to simulate space radiation effects, aiding the development of more resilient detectors for future astronomical missions.

Contribution

It introduces a new irradiation setup with high flux uniformity and comprehensive monitoring, enabling early-stage testing of large-area silicon X-ray detectors for space applications.

Findings

Successful irradiation campaigns on silicon drift detectors

Enhanced understanding of soft proton effects on detector performance

Setup allows testing of large detectors with uniform proton flux

Abstract

Protons that are trapped in the Earth's magnetic field are one of the main threats to astronomical X-ray observatories. Soft protons, in the range from tens of keV up to a few MeV, impinging on silicon X-ray detectors can lead to a significant degradation of the detector performance. Especially in low earth orbits an enhancement of the soft proton flux has been found. A setup to irradiate detectors with soft protons has been constructed at the Van-de-Graaff accelerator of the Physikalisches Institut of the University of T\"ubingen. Key advantages are a high flux uniformity over a large area, to enable irradiations of large detectors, and a monitoring system for the applied fluence, the beam uniformity, and the spectrum, that allows testing of detector prototypes in early development phases, when readout electronics are not yet available. Two irradiation campaigns have been performed so far with this setup. The irradiated detectors are silicon drift detectors, designated for the use on-board the LOFT space mission. This paper gives a description of the experimental setup and the associated monitoring system.