Measurement of the absolute number of photons of the hard X-ray beamline at the Linac Coherent Light Source

X-ray free-electron lasers provide intense pulses of coherent X-rays with a short pulse duration. These sources are chaotic by nature and therefore, to be used at their full potential, require that every X-ray pulse is characterized in terms of various relevant properties such as intensity, photon energy, position and timing. Diagnostics are for example installed on an X-ray beamline to specifically monitor the intensity of individual X-ray pulses. To date, these can however only provide a single-shot value of the relative number of photons per shot. Here are reported measurements made in January 2015 of the absolute number of photons in the hard X-ray regime at LCLS which is typically 3.5   ×   1011   photons shot − 1 between 6 and 9.5   keV at the X-ray Pump – Probe instrument. Moreover, an average transmission of ≈ 62% of the hard X-ray beamline over this energy range is measured and the third-harmonic content of ≈ 0.47% below 9   keV is characterized.

Source: Journal of Synchrotron Radiation - February 11, 2019 Category: Physics Authors: Song, S. Alonso-Mori, R. Chollet, M. Feng, Y. Glownia, J.M. Lemke, H.T. Sikorski, M. Zhu, D. Moeller, S. Lee, H.J. Hunter, M.S. Carini, G. Tiedtke, K. Jastrow, U. Sorokin, A. Richter, M. Owada, S. Tono, K. Saito, N. Tanaka, T. Kato, M. Yabashi, M. Robert, Tags: FEL hard X-rays absolute intensity research papers Source Type: research