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Title: Implications of the focal beam profile in serial femtosecond crystallography

Abstract

The photon density profile of an X-ray free-electron laser (XFEL) beam at the focal position is a critical parameter for serial femtosecond crystallography (SFX), but is difficult to measure because of the destructive power of the beam. A novel high intensity radiation induced phasing method (HIRIP) has been proposed as a general experimental approach for protein structure determination, but has proved to be sensitive to variations of the X-ray intensity, with uniform incident fluence desired for best performance. Here we show that experimental SFX data collected at the nano-focus chamber of the Coherent X-ray Imaging end-station at the Linac Coherent Light Source using crystals with a limited size distribution suggests an average profile of the X-ray beam that has a large variation of intensity. We propose a new method to improve the quality of high fluence data for HI-RIP, by identifying and removing diffraction patterns from crystals exposed to the low intensity region of the beam. The method requires crystals of average size comparable to the width of the focal spot.

Authors:
 [1];  [1];  [2]
  1. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Center for Free-Electron Laser Science
  2. Univ. of Auckland (New Zealand)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1194678
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Proceedings of SPIE - The International Society for Optical Engineering
Additional Journal Information:
Journal Volume: 9511; Conference: Damage to VUV, EUV, and X-ray Optics V, Prague (Czech Republic), 13 Apr 2015; Journal ID: ISSN 0277-786X
Publisher:
SPIE
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS

Citation Formats

Galli, Lorenzo, Chapman, Henry N., and Metcalf, Peter. Implications of the focal beam profile in serial femtosecond crystallography. United States: N. p., 2015. Web. doi:10.1117/12.2182654.
Galli, Lorenzo, Chapman, Henry N., & Metcalf, Peter. Implications of the focal beam profile in serial femtosecond crystallography. United States. doi:10.1117/12.2182654.
Galli, Lorenzo, Chapman, Henry N., and Metcalf, Peter. Tue . "Implications of the focal beam profile in serial femtosecond crystallography". United States. doi:10.1117/12.2182654.
@article{osti_1194678,
title = {Implications of the focal beam profile in serial femtosecond crystallography},
author = {Galli, Lorenzo and Chapman, Henry N. and Metcalf, Peter},
abstractNote = {The photon density profile of an X-ray free-electron laser (XFEL) beam at the focal position is a critical parameter for serial femtosecond crystallography (SFX), but is difficult to measure because of the destructive power of the beam. A novel high intensity radiation induced phasing method (HIRIP) has been proposed as a general experimental approach for protein structure determination, but has proved to be sensitive to variations of the X-ray intensity, with uniform incident fluence desired for best performance. Here we show that experimental SFX data collected at the nano-focus chamber of the Coherent X-ray Imaging end-station at the Linac Coherent Light Source using crystals with a limited size distribution suggests an average profile of the X-ray beam that has a large variation of intensity. We propose a new method to improve the quality of high fluence data for HI-RIP, by identifying and removing diffraction patterns from crystals exposed to the low intensity region of the beam. The method requires crystals of average size comparable to the width of the focal spot.},
doi = {10.1117/12.2182654},
journal = {Proceedings of SPIE - The International Society for Optical Engineering},
issn = {0277-786X},
number = ,
volume = 9511,
place = {United States},
year = {2015},
month = {5}
}