Data collection strategies for time-resolved X-ray free electron laser diffraction, and 2-color methods.

POSTER

Abstract

We compare three schemes for time-resolved X-ray diffraction from protein nanocrystals using an X-ray free-electron laser. We find expressions for errors in structure factor measurement using Monte Carlo pump-probe method of data analysis with a liquid jet, the fixed sample pump-probe (goniometer) method, and a proposed two-color method. Here, an optical pump pulse arrives between X-ray pulses of slightly different energies which hit the same nanocrystal, using a weak first X-ray pulse which does not damage the sample. (Radiation damage is outrun in the other cases.) This two-color method, in which separated Bragg spots are impressed on the same detector readout, eliminates stochastic fluctuations in crystal size, shape, and orientation and is found to require two orders of magnitude fewer diffraction patterns than the currently used Monte Carlo liquid jet method, for 1{\%} accuracy. Detailed simulations provided for cathepsin B and IC3 crystals. While the error is independent of the number of shots for the dose-limited goniometer method, it falls off inversely as the square root of the number of shots for the two-color and Monte Carlo methods, with a much smaller pre-factor for the two-color mode, when the first shot is below the damage threshold.

Authors

  • Chufeng Li

    Arizona State University

  • Scott D. Bergesen

    Santa Fe Institute, Arizona State University, Department of Physics and Center for Biological Physics, Arizona State University, Brigham Young University Department of Physics and Astronomy, Brigham Young University, Utah Valley University, Dixie State College, Advisor, Student, Massachusetts Institute of Technology, Thomas Jefferson National Accelerator Laboratory, Colorado College, United States Air Force Academy, Georgia Institute of Technology, Utah State University, Brigham Young University - Idaho, Utah State University- Logan, National Institute of Standards and Technology, Humboldt State University, UC Santa Cruz, Institut de Chimie des Substances Naturelles, Arizona State Univ, University of Colorado at Colorado Springs, National Jewish Health, Department of Physics, The University of Texas at Austin, Department of Physics, New Mexico State University, U. S. Air Force Academy, Brigham Young Univ - Provo, University of New South Wales, University of Texas, University of Warwick, University of Louisiana, Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA., Center for Materials Genomics, Department of Mechanical Engineering and Materials Science and Department of Physics, Duke University, Durham, North Ca, Duke University, Durham, North Carolina., Brigham Young University -- Provo, Utah, General Atomics -- San Diego, California, Department of Mathematics, University of British Columbia, Department of Physics, Arizona State University, UC Riverside, UMASS, STScI, NOAO, UT Austin, Texas A&M, Arizona State Univeristy, New Mexico State Univ, Los Alamos National Laboratory, Colorado State Univ, Department of Physics, Oregon State University, Colorado School of Mines, University of Alaska, Fairbanks, The Peac Institute of Multiscale Modeling, UNSW Canberra

  • John Spence

    Arizona State University