Single-shot experiments at the soft X-FEL FERMI using a back-side-illuminated scientific CMOS detector.

Cyril Léveillé,Kewin Desjardins,Matteo Pancaldi,Renaud Delaunay,Boris Vondungbo,Emanuele Pedersoli,Dario De Angelis,Flavio Capotondi,Horia Popescu,Nicolas Jaouen,Emmanuelle Jal,Marcel Hennes

doi:10.1107/s1600577521012303

Abstract

The latest Complementary Metal Oxide Semiconductor (CMOS) 2D sensors now rival the performance of state-of-the-art photon detectors for optical application, combining a high-frame-rate speed with a wide dynamic range. While the advent of high-repetition-rate hard X-ray free-electron lasers (FELs) has boosted the development of complex large-area fast CCD detectors in the extreme ultraviolet (EUV) and soft X-ray domains, scientists lacked such high-performance 2D detectors, principally due to the very poor efficiency limited by the sensor processing. Recently, a new generation of large back-side-illuminated scientific CMOS sensors (CMOS-BSI) has been developed and commercialized. One of these cost-efficient and competitive sensors, the GSENSE400BSI, has been implemented and characterized, and the proof of concept has been carried out at a synchrotron or laser-based X-ray source. In this article, we explore the feasibility of single-shot ultra-fast experiments at FEL sources operating in theEUV/soft X-ray regime with an AXIS-SXR camera equipped with the GSENSE400BSI-TVISB sensor. We illustrate the detector capabilities by performing a soft X-ray magnetic scattering experiment at the DiProi end-station of the FERMI FEL. These measurements show the possibility of integrating this camera for collecting single-shot images at the 50 Hz operation mode of FERMI with a cropped image size of 700× 700 pixels. The efficiency of the sensor at a working photon energy of 58 eV and the linearity over the large FEL intensity have been verified. Moreover, on-the-fly time-resolved single-shot X-ray resonant magnetic scattering imaging from prototype Co/Pt multilayer films has been carried out with a time collection gain of 30 compared to the classical start-and-stop acquisition method performed with the conventional CCD-BSI detector available at the end-station.

Highlights

Nowadays, commercially available Complementary Metal Oxide Semiconductor (CMOS) 2D sensors are largely used for many visible applications or in the X-ray domain coupled with scintillators
In order to safely test the linearity of the CMOS, the free-electron lasers (FELs) intensity has been kept far from the damage threshold of the sensor based on our previous X-ray characterization (Desjardins et al, 2020)
We have shown the advantages that the CMOS camera could bring to FEL time-resolved experiments in terms of gain in data acquisition, but we would like to illustrate that by operating the CMOS camera at 50 Hz, corresponding to the FERMI main frequency, X-ray photon correlation spectroscopy (XPCS) experiments for pump– probe ultrafast dynamics in the ultra-fast time domain can be performed

Summary

Introduction

Commercially available Complementary Metal Oxide Semiconductor (CMOS) 2D sensors are largely used for many visible applications or in the X-ray domain coupled with scintillators. The GPIXEL (https://www.gpixel.com/) CMOS GSENSE400BSI is the first large production of this kind of sensor whose manufacturing process is compatible with soft X-ray applications due to the absence of a microlens, window and to the thin coating applied to the surface It is based on 2048 Â 2048 pixels of 11 mm with two gains and a combined gain mode to achieve the high dynamic range (HDR). The first utilization of this device opened up perspectives for soft X-ray ptychography (Mille et al, 2022), soft X-ray scattering techniques (Desjardins et al, 2020; Marras et al, 2021) and other applications, such as soft X-ray fluorescence (Staeck et al, 2021) Another obvious application concerns the implementation of such a class of detectors at ultra-short X-ray sources (laser-based X-ray source or free-electron laser), where the low frame rate of the standard commercially available CCD-BSI (see, for example, Vodungbo et al, 2012; Wang et al, 2012) limits the time of data collection. Sorting the collected data on the basis of pulse-deposited energy, we unequivocally observed a loss of the magnetic scattering efficiency before the sample damage

Methods

Results

Conclusion