Automated identification and classification of single particle serial femtosecond X-ray diffraction data

Abstract

Abstract:The first hard X-ray laser, the Linac Coherent Light Source (LCLS), produces 120 shots per second. Particles injected into the X-ray beam are hit randomly and in unknown orientations by the extremely intense X-ray pulses, where the femtosecond-duration X-ray pulses diffract from the sample before the particle structure is significantly changed even though the sample is ultimately destroyed by the deposited X-ray energy. Single particle X-ray diffraction experiments generate data at the FEL repetition rate, resulting in more than 400,000 detector readouts in an hour, the data stream during an experiment contains blank frames mixed with hits on single particles, clusters and contaminants. The diffraction signal is generally weak and it is superimposed on a low but continually fluctuating background signal, originating from photon noise in the beam line and electronic noise from the detector. Meanwhile, explosion of the sample creates fragments with a characteristic signature. Here, we describe methods based on rapid image analysis combined with ion Time-of-Flight (ToF) spectroscopy of the fragments to achieve an efficient, automated and unsupervised sorting of diffraction data. The studies described here form a basis for the development of real-time frame rejection methods, e.g. for the European XFEL, which is expected to produce 100 million pulses per hour. ©2014 Optical Society of America

Time-resolved x-ray imaging of a laser-induced nanoplasma and its neutral residuals

“…The method of single-shot imaging requires a large amount of data to be collected in order to ensure meaningful statistics. Despite opening new possibilities it also demands novel filtering routines [51]. From the evolution-initiating IR pulse only a fluorescence is recorded and not a scattering pattern.…”

Current Status of Single Particle Imaging with X-ray Lasers

“…Coherent diffractive imaging experiments with X-ray free-electron lasers (XFEL-CDI) have studied a wide range of samples including man-made objects, nano-materials, clusters, and aerosol particles in the gas phase [101,[118][119][120][121][122][123][124][125][126][127][128][129][130][131][132]. Many of these were used to test the validity of XFEL-CDI and included measurements of the morphology of complex structures, functional imaging method development, and dynamic changes under a stimulus (pump-probe).…”

CFEL–ASG Software Suite(CASS): usage for free-electron laser experiments with biological focus

“…CASS has been used successfully in a variety of different experiments (Andreasson et al, 2014;Barends, White et al, 2015;Barends, Foucar et al, 2015Barty et al, 2012;Boll et al, 2013Boll et al, , 2014Botha et al, 2015;Boutet et al, 2012Boutet et al, , 2015Bublitz et al, 2015;Chapman et al, 2011;Erk et al, 2014Erk et al, , 2013aFrasinski et al, 2013;Fukuzawa et al, 2013;Gomez et al, 2014;Gorkhover et al, 2012;Johansson et al, 2012;Kü pper et al, 2014;Kassemeyer et al, 2012;Koopmann et al, 2012;Loh et al, 2013Loh et al, , 2012Lomb et al, 2011;Martin, Loh et al, 2012;Martin, Wang et al, 2012;Motomura et al, 2013;Mucke et al, 2014;Park et al, 2013;Pedersoli et al, 2013;Rudek et al, 2013Rudek et al, , 2012van der Schot et al, 2015;Seibert et al, 2011;Starodub et al, 2012;Stern et al, 2014;Yoon et al, 2011;Zhaunerchyk et al, 2013), including the aforementioned single-particle and the emerging SFX experiments. Moreover, it has been used for experiments at different FEL facilities such as LCLS, SACLA and FLASH.…”

“…Hit finding in single-particle experiments is different from the process in SFX experiments. Andreasson et al (2014) proposed an algorithm that allows the detection of non-empty frames, when the number of frames containing data is much less than the number of empty frames. This algorithm can easily be implemented in CASS using the existing modules.…”