Phase retrieval in nanocrystallography

Joe P J Chen, John Spence, Rick P. Millane

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Protein X-ray crystallography is a method for determining the three-dimensional structures of large biological molecules by analysing the amplitudes of X-rays scattered from a crystalline specimen of the molecule under study. Conventional structure determination in protein crystallography requires chemical modification to the sample and collection of additional data in order to solve the corresponding phase problem. There is an urgent need for a direct (digital) low-resolution phasing method that does not require modified specimens. Whereas diffraction from large crystals corresponds to samples (so-called Bragg samples) of the amplitude of the Fourier transform of the scattering density, the diffraction from very small crystals allows measurement of the diffraction amplitude between the Bragg samples. Although highly attenuated, these additional measurements offer the possibility of iterative phase retrieval without the use of ancillary experimental data. In this study we examine the noise characteristics of small-crystal diffraction and propose a data selection strategy to improve the quality of reconstructions using iterative phase retrieval algorithms. Simulation results verify that a higher noise level can be tolerated by using such a data selection strategy.

Original languageEnglish (US)
Title of host publicationImage Reconstruction from Incomplete Data VII
StatePublished - 2012
EventImage Reconstruction from Incomplete Data VII - San Diego, CA, United States
Duration: Aug 14 2012Aug 15 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherImage Reconstruction from Incomplete Data VII
Country/TerritoryUnited States
CitySan Diego, CA


  • Nanocrystallography
  • Phase retrieval
  • Selective sampling
  • Shape transform
  • X-ray free-electron laser

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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