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Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source



Uwe Arp, Alexander Sorokin, Ulf Jastrow, Pavle Jurani?, Svea Kreis, Mathias Richter, Yiping Feng, Dennis Nordlund, Kai Tiedtke, Philip Heimann, Bob Nagler, Hae Ja Lee, Stephanie Mack, Marco Cammarata, Oleg Krupin, Marc Messerschmidt, Michael Holmes , Michael Rowen, William Schlotter, Stefan Moeller, Joshua Turner


This paper reports novel measurements of x-ray optical radiation on an absolute scale from a recently developed source of radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the physics behind the electromagnetic radiation measurements, and then present the transmission results of a recently commissioned x-ray instrument at the Linac Coherent Light Source (LCLS) by using an absolute detector temporarily placed at the down stream end of the instrument. This provides an estimation of the reflectivity of all x-ray optical elements in the beamline as well as the most important parameter for a new instrument focused primarily on studying materials via resonant processes: the photon number per bandwidth per pulse. This parameter is important for many experiments which need to understand the trade-offs associated with experiments with high energy resolution compared to high flux. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content.
Applied Optics


Free electron laser, Gas detector


Arp, U. , , A. , Jastrow, U. , , P. , Kreis, S. , Richter, M. , , Y. , , D. , Tiedtke, K. , , P. , , B. , , H. , , S. , , M. , , O. , , M. , , M. , , M. , Schlotter, W. , Moeller, S. and , J. (2014), Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source, Applied Optics, [online], (Accessed April 16, 2024)
Created August 25, 2014, Updated November 10, 2018