Energy Dependent Features of X-ray Signals in a GridPix Detector

TL;DR

This paper presents a detailed calibration and analysis of an argon/isobutane GridPix detector's response to soft X-rays, focusing on energy resolution and event characteristics across a range of energies.

Contribution

It provides the first comprehensive calibration of a GridPix detector with soft X-rays and analyzes its linearity and energy resolution in detail.

Findings

Energy resolution better than 10% above 2 keV

Linear response of the detector across studied energies

Characterization of event features at different energies

Abstract

We report on the calibration of an argon/isobutane (97.7 %/2.3 %)-filled GridPix detector with soft X-rays (277 eV to 8 keV) using the variable energy X-ray source of the CAST Detector Lab at CERN. We study the linearity and energy resolution of the detector using both the number of hit pixels and the total measured charge as energy measures. For the latter, the energy resolution {\sigma}_E/E is better than 10 % (20 %) for energies above 2 keV (0.5 keV). Several characteristics of the recorded events are studied.