Journal Article

High-brightness self-seeded X-ray free-electron laser covering the 3.5 keV to 14.6 keV range

Oh Bonggi, Lee, Sang Jae, Park Gisu, Chang-Ki, Min, Heo Hoon, Kim, Seonghan, Shvyd’ko Yuri, Yang Haeryong, Kim Changbum, Chun, Sae Hwan, Deming, Shu, Terentyev Sergey, Nam Inhyuk, Suh Young Jin, Kim Gyujin, HyoJung, Hyun, Eom Intae, Rah Seungyu, Park, Jaehyun, Heung-Sik, Kang, Shim, Chi Hyun, Cho, Myung Hoon, Ko, Jun Ho, Kim Jangwoo, Kwang-Je, Kim, Lee, Jae Hyuk, Blank, Vladimir, Min-Jae, Kim, Kim, Kyung Sook, Park Sehan, Na Donghyun

2021

Overview

A self-seeded X-ray free-electron laser (XFEL) is a promising approach to realize bright, fully coherent free-electron laser (FEL) sources in the hard X-ray domain that have been a long-standing issue with longitudinal coherence remaining challenging. At the Pohang Accelerator Laboratory XFEL, we have demonstrated a hard X-ray self-seeded XFEL with a peak brightness of 3.2 × 1035 photons s–1 mm–2 mrad–2 0.1% bandwidth (BW)–1 at 9.7 keV. The bandwidth (0.19 eV) is about 1/70 times as wide (close to the Fourier transform limit) and the peak spectral brightness is 40 times higher than in self-amplified spontaneous emission (SASE), with substantial improvements in the stability of self-seeding and noticeably suppressed pedestal effects. We could reach an excellent self-seeding performance at a photon energy of 3.5 keV (lowest) and 14.6 keV (highest) with the same stability as the 9.7 keV self-seeding. The bandwidth of the 14.6 keV seeded FEL was 0.32 eV, and the peak brightness was 1.3 × 1035 photons s–1 mm–2 mrad–2 0.1%BW–1. We show that the use of seeded FEL pulses with higher reproducibility and a cleaner spectrum results in serial femtosecond crystallography data of superior quality compared with data collected using SASE mode.A hard X-ray self-seeded X-ray free-electron laser at the Pohang Accelerator Laboratory provides X-ray pulses with peak brightness of 3.2 × 1035 photons s–1 mm–2 mrad–2 0.1%BW–1 at 9.7 keV and a very small shot-to-shot electron energy jitter of 0.012%.

• Publisher: Nature Publishing Group
• Subject: Bandwidths / Brightness / Crystallography / Electron energy / Electrons / Fourier transforms / Free electron lasers / Laboratories / Lasers / Photons / Spontaneous emission / Stability / Vibration