Single-shot analysis of hard x-ray laser radiation using a noninvasive grating spectrometer

Abstract

We present a spectrometer setup based on grating dispersion for hard x-ray free-electron lasers. This setup consists of a focusing spectrometer grating and a charge-integrating microstrip detector. Measurement results acquired at Linac Coherent Light Source are presented, demonstrating noninvasive monitoring of single-shot spectra with a resolution of 2.0×10(-4) ±0.3×10(-4) at photon energy of 6 keV with more than 95% transmission of the main beam.

Perspective: Opportunities for ultrafast science at SwissFEL

“…The initial phase of operation will cover the first two experimental hutches, with the third planned for installation in the coming years. The beamlines include several different diagnostics elements to report for every pulse the X-ray spectrum, 76–78 energy, and beam position 79,80 . For pump-probe studies, a specialized timing diagnostic tool provides shot-to-shot information on the relative time-delay between the optical laser excitation pulse and the probe X-ray pulse with an accuracy of <10 fs 55,81 …”

A beam branching method for timing and spectral characterization of hard X-ray free-electron lasers

“…In this paper, we propose a scheme using a transmission grating to split an x-ray beam into a main branch and several sub-branches, which are dedicated for experiments and diagnostics, respectively. Similar approaches have been used for building a split-and-delay line 7 as well as for spectral monitoring 31,32 combined with a thin bent analyzer crystal 33 . Here, we utilized the +1st-order and −1st-order branches for measuring the spectrum and the arrival timing jitter, respectively (see Fig.…”

High-resolution single-shot spectral monitoring of hard x-ray free-electron laser radiation

“…1(b)] [9] and one based on a focusing transmission grating [ Fig. 1(c)] [10]. The spectrometer based on a thin bent crystal [9] offers a high spectral resolution of better than ∼0.2 eV, as well as a nondemanding alignment, but causes significant beam intensity loss of up to 50% at lower photon energies due to absorption.…”

“…The spectrometer based on a thin bent crystal [9] offers a high spectral resolution of better than ∼0.2 eV, as well as a nondemanding alignment, but causes significant beam intensity loss of up to 50% at lower photon energies due to absorption. The grating-based method [10] has the advantages of high x-ray beam transmission and radiation hardness, but suffers from a limited spectral resolution of the order of 1.5 eV.…”

“…In this Article we present a novel single-shot on-line spectrometer for hard x-rays [ Fig. 2(a)] that has the benefits of both the diffraction grating [10] and the high-resolution crystal analyzer methods [6,9], yet overcomes their respective disadvantages. The key aspect for such an achievement is to combine the noninvasive, radiation hard, and highly transmissive diffraction grating with one of the high-resolution crystal spectral analyzers [6,9].…”