Temporal X-ray Reconstruction using Temporal and Spectral Measurements at LCLS
Abstract
Transverse deflecting structures (TDSs) are widely used in accelerator physics to measure the longitudinal density of particle bunches. When used in combination with a dispersive section, the whole longitudinal phase space density can be imaged. At the Linac Coherent Light Source (LCLS), the installation of such a device downstream of the undulators enables the reconstruction of the X-ray temporal intensity profile by comparing longitudinal phase space distributions with lasing on and lasing off. However, the resolution of this TDS is limited to around 1 fs rms (root mean square), and therefore, it is not possible to resolve single self-amplified spontaneous emission (SASE) spikes within an X-ray photon pulse. By combining the power spectrum from a high resolution photon spectrometer and the temporal structure from the TDS, the overall resolution is enhanced, thus allowing the observation of temporal, single SASE spikes. The combined data from the spectrometer and the TDS is analysed using an iterative algorithm to obtain the actual intensity profile. In this paper, we present some improvements to the reconstruction algorithm as well as real data taken at LCLS.
Additional Information
© The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 23 December 2019 Accepted 18 May 2020. Published 17 June 2020. This work was supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-76SF00515. Code availability: The algorithm and datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Author Contributions: A.A.L. conceived the algorithm. A.A.L., V.A.J., and F.C. programmed the algorithm and tested it on simulation data, with inputs from Z.H., D.R., and T.J.M. during development. F.C., Y.D., J.K., T.J.M., and D.R. performed the measurement. F.C. and T.J.M. analysed the measurement data. F.C. wrote the manuscript in consultation with A.A.L., T.J.M., D.R., J.R.-S., and M.V. The authors declare no competing interests.Attached Files
Published - s41598-020-66220-5.pdf
Submitted - 1911.06090.pdf
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Additional details
- PMCID
- PMC7300001
- Eprint ID
- 103958
- Resolver ID
- CaltechAUTHORS:20200622-104138354
- DE-AC02-76SF00515
- Department of Energy (DOE)
- Created
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2020-06-23Created from EPrint's datestamp field
- Updated
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2022-02-15Created from EPrint's last_modified field