# Characterization of the ePix100a and the FastCCD Semiconductor Detectors for the European XFEL

## TL;DR

This paper characterizes the ePix100a and FastCCD semiconductor detectors used at the European XFEL, evaluating their performance to improve data quality in high-brilliance, high-repetition-rate X-ray experiments.

## Contribution

It provides a detailed characterization and analysis of the ePix100a and FastCCD detectors, introducing methods to assess their performance for XFEL applications.

## Key findings

- Detectors operate effectively at 10 Hz train repetition rate.
- Performance metrics align with state-of-the-art analysis techniques.
- Characterization improves calibration and data quality for XFEL experiments.

## Abstract

The European X-ray Free Electron Laser (EuXFEL) is a research facility providing spatially coherent X-ray flashes in the energy range from 0.25keV to 25keV of unprecedented brilliance and with unique time structure: X-ray pulses with a 4.5 MHz repetition rate arranged in trains with 2700 pulses every 100 ms. The facility operates three photon beamlines called SASE 1, SASE 2 and SASE 3. Each of the beamlines is hosting two scientific experiments. The SASE 1 beamline started its user operation in September 2017, followed by successful first lasing at the SASE 2 beamline in May 2018. Early user experiments are planned to start in 2019 at this beamline, while early user experiments for the SASE 3 beamline are scheduled for the end of 2018. The quality of the experimental data will gain substantial benefits from an accurate characterization and calibration of the X-ray detectors. Supplementing high repetition rate detectors at MHz speeds, slower detectors such as the ePix100a and the FastCCD will be operated at the train repetition rate of 10 Hz. These 2D silicon pixelized detectors use fast parallel column-wise readout implemented as a CCD or as a hybrid pixel detector. In the following, characterization and analysis approaches for the FastCCD and the ePix100a detectors are discussed and the performance of the detectors is evaluated using appropriate state-of-the-art analysis techniques.