Publication
Maximum likelihood methods in DIALS
Authors:
James
Parkhurst
(Diamond Light Source)
,
Graeme
Winter
(Diamond Light Source)
,
David
Waterman
(CCP4)
,
Richard
Gildea
(Diamond Light Source)
,
Luis
Fuentes-montero
(Diamond Light Source)
,
Garib
Murshudov
(Laboratory of Molecular Biology, Cambridge)
,
Gwyndaf
Evans
(Diamond Light Source)
Co-authored by industrial partner:
No
Type:
Conference Paper
Conference:
Twenty-Fourth Congress and General Assembly of the International Union of Crystallography
Peer Reviewed:
No
State:
Published (Approved)
Published:
August 2017
Abstract: In macromolecular crystallography, integration programs - such as DIALS (Waterman et al. 2013) - are used to estimate the intensities of Bragg reflections recorded on a series of X-ray diffraction images. The reflection intensities are estimated using the following procedure. A model for the shape of the reflection profile is estimated from a set of strong reflections. This model is then applied to each reflection in order to estimate the size and shape of the reflection on the detector surface and to label each pixel as either foreground or background. The intensity of each reflection is then estimated (in the case of summation integration) by summing the total counts minus the estimated background counts in the foreground region. Since the background level under the reflection peak cannot be measured directly, it is estimated from the surrounding background pixels assuming a given model.
Journal Keywords: Integration; maximum likelihood; modelling
Subject Areas:
Technique Development
Technical Areas:
Data acquisition
,
Detectors
Added On:
05/01/2018 14:11
Discipline Tags:
Technical Tags: