A compact single-shot soft X-ray photon spectrometer for free electron laser diagnostics
preprintposted on 2023-06-08, 13:05 authored by Kirk A. Larsen, Kurtis Borne, Razib Obaid, Andrei Kamalov, Yusong Liu, Xinxin Cheng, Justin James, Taran Driver, Kenan Li, Yanwei Liu, Anne Sakdinawat, Christian David, Thomas J. A. Wolf, James Cryan, Peter Walter, Ming-Fu Lin
The photon spectrum from free-electron laser (FEL) light sources offers valuable information in time-resolved experiments and machine optimization in the spectral and temporal domains. We have developed a compact single-shot photon spectrometer to diagnose soft X-ray spectra. The spectrometer consists of an array of off-axis Fresnel zone plates (FZP) that act as transmission-imaging gratings, a Ce-YAG scintillator, and a microscope objective to image the scintillation target onto a two-dimensional imaging detector. This spectrometer operates in an energy range which covers absorption edges associated with several atomic constituents carbon, nitrogen, oxygen, and neon. The spectrometer's performance is demonstrated at a repetition rate of 120 Hz, but our detection scheme can be easily extended to 200 kHz spectral collection by employing a fast complementary metal oxide semiconductor (CMOS) line-scan camera to detect the light from the scintillator. This compact photon spectrometer provides an opportunity for monitoring the spectrum downstream of an endstation in a limited space environment with subelectronvolt energy resolution.