An X-ray gas monitor for free-electron lasers

A novel X-ray gas monitor (XGM) has been developed which allows the measurement of absolute photon pulse energy and photon beam position at all existing and upcoming free-electron lasers (FELs) over a broad spectral range covering vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and soft and hard X-rays. The XGM covers a wide dynamic range from spontaneous undulator radiation to FEL radiation and provides a temporal resolution of better than 200   ns. The XGM consists of two X-ray gas-monitor detectors (XGMDs) and two huge-aperture open electron multipliers (HAMPs). The HAMP enhances the detection efficiency of the XGM for low-intensity radiation down to 105 photons per pulse and for FEL radiation in the hard X-ray spectral range, while the XGMD operates in higher-intensity regimes. The relative standard uncertainty for measurements of the absolute photon pulse energy is well below 10%, and down to 1% for measurements of relative pulse-to-pulse intensity on pulses with more than 1010 photons per pulse. The accuracy of beam-position monitoring in the vertical and horizontal directions is of the order of 10   µ m.

Source: Journal of Synchrotron Radiation - June 11, 2019 Category: Physics Authors: Sorokin, A.A. Bican, Y. Bonfigt, S. Brachmanski, M. Braune, M. Jastrow, U.F. Gottwald, A. Kaser, H. Richter, M. Tiedtke, K. Tags: free-electron lasers vacuum ultraviolet soft X-rays hard X-rays photon diagnostics research papers Source Type: research