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by Alex de Maria, Armando Solé, and Andy Gotz on behalf of the ESRF Data Policy Implementation Team The ESRF, the European Synchroton, has recently adopted a Data Policy which will archive all data collected at the ESRF for 10 years and... more
by Alex de Maria, Armando Solé, and Andy Gotz on behalf of the ESRF Data Policy Implementation Team The ESRF, the European Synchroton, has recently adopted a Data Policy which will archive all data collected at the ESRF for 10 years and be made freely available as Open Data after an initial embargo period of 3 years (can be extended on request). Currently the ESRF produces 2 PBs of raw data annually. This means archiving at least 70 PBs of data over the next 10 years if one assumes a linear growth of data production. The Data Policy introduces a number of new challenges for the ESRF. These challenges include persistent user identities, user rights, metadata definition and standardisation, automated collecting of metadata, metadata catalogue, data containers, long term archiving, and finding and re-using data. This paper will describe how these challenges are being solved. The paper describes how it is possible for a mature synchrotron to adopt and implement a modern Data Policy larg...
Structural studies of light-driven conformational changes in a photosynthetic reaction centre.
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A scanning-type crystal spectrometer for high-resolution Compton profile measurements has been constructed at the High Energy Inelastic Scattering Beamline (ID15B) of the ESRF. Radiation from a seven-period asymmetrical permanent-magnet... more
A scanning-type crystal spectrometer for high-resolution Compton profile measurements has been constructed at the High Energy Inelastic Scattering Beamline (ID15B) of the ESRF. Radiation from a seven-period asymmetrical permanent-magnet wiggler or from a superconducting wavelength shifter is focused horizontally onto the sample by a bent-crystal monochromator. Typical energies are 30, 50 and 60 keV, the flux on the sample is 1012 photons s−1, and the relative energy bandwidth is 3 × 10−4. The spectrometer operates in the Rowland circle geometry, where the sample is fixed and the cylindrically bent analyser crystal and the detector move on the focusing circle by synchronized translations and rotations. The main detector is a large-diameter NaI scintillation counter, the incident beam is monitored by an Si diode, and scattering from the sample is detected using a Ge detector. The recorded spectrum is corrected for the energy-dependent response of the spectrometer, background and multi...
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Structural studies of light-driven conformational changes in a photosynthetic reaction centre.
The production of three-dimensional crystallographic structural information of macromolecules can now be thought of as a pipeline which is being streamlined at every stage from protein cloning, expression and purification, through... more
The production of three-dimensional crystallographic structural information of macromolecules can now be thought of as a pipeline which is being streamlined at every stage from protein cloning, expression and purification, through crystallisation to data collection and structure solution. Synchrotron X-ray beamlines are a key section of this pipeline as it is at these that the X-ray diffraction data that ultimately leads to the elucidation of macromolecular structures are collected. The burgeoning number of macromolecular crystallography (MX) beamlines available worldwide may be enhanced significantly with the automation of both their operation and of the experiments carried out on them. This paper reviews the current situation and provides a glimpse of how a MX beamline may look in the not too distant future.
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... Arnaud Clere, Frank Felisaz, David Flot, Julien Huet, Pierre-Yves Lanquetin, Bernard Lavault, Lionel Mallet, Andrew McCarthy, Raimond Ravelli, Andrew Thompson; (MRC-France) Hugo Caserotto, Ludovic Launer, Martin Walsh. References. 1.... more
... Arnaud Clere, Frank Felisaz, David Flot, Julien Huet, Pierre-Yves Lanquetin, Bernard Lavault, Lionel Mallet, Andrew McCarthy, Raimond Ravelli, Andrew Thompson; (MRC-France) Hugo Caserotto, Ludovic Launer, Martin Walsh. References. 1. Norvell, JC and Zapp Machalek, A ...
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... Arnaud Clere, Frank Felisaz, David Flot, Julien Huet, Pierre-Yves Lanquetin, Bernard Lavault, Lionel Mallet, Andrew McCarthy, Raimond Ravelli, Andrew Thompson; (MRC-France) Hugo Caserotto, Ludovic Launer, Martin Walsh. References. 1.... more
... Arnaud Clere, Frank Felisaz, David Flot, Julien Huet, Pierre-Yves Lanquetin, Bernard Lavault, Lionel Mallet, Andrew McCarthy, Raimond Ravelli, Andrew Thompson; (MRC-France) Hugo Caserotto, Ludovic Launer, Martin Walsh. References. 1. Norvell, JC and Zapp Machalek, A ...
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Directional-spin-dependent Compton profiles of ferromagnetic hexagonal close packed cobalt metal have been measured with 117 keV and 167 keV circularly polarized synchrotron radiation at the new ESRF high energy beamline. Significantly... more
Directional-spin-dependent Compton profiles of ferromagnetic hexagonal close packed cobalt metal have been measured with 117 keV and 167 keV circularly polarized synchrotron radiation at the new ESRF high energy beamline. Significantly improved resolution was achieved at the higher energy. The results have been compared with the profile predicted from an augmented plane wave (APW) calculation of the electron momentum density in the hexagonal phase. No significant difference was found between the c-axis and the basal plane magnetic profiles. The experiments show that there is substantially more 3d spin density at high momentum than in the model calculation. After correcting for this deficiency we find that the 4s-p component of the momentum density remains significantly different than predicted.
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Investigations of spin densities in ferromagnetic materials using magnetic Compton scattering are reported. At the high-energy beamline ID15 at the ESRF, experiments have been carried out utilizing the high flux at very high photon... more
Investigations of spin densities in ferromagnetic materials using magnetic Compton scattering are reported. At the high-energy beamline ID15 at the ESRF, experiments have been carried out utilizing the high flux at very high photon energies. Energies from 60 up to 1000 keV have been used for investigations of experimental resolution, cross section, spin moments and momentum distribution. Optimized conditions are found for photon energies from 200 to 250 keV with a momentum resolution < 0.4 a.u. and a doubled magnetic effect compared with earlier measurements. In the determination of absolute spin moments multiple scattering has to be taken into account.
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ABSTRACT The spin moments of DyFe2 and ErFe2 samples have been determined from magnetic Compton scattering experiments performed at the KEK Accumulation Ring with 47.1 keV circularly polarized synchrotron radiation at temperatures 50-355... more
ABSTRACT The spin moments of DyFe2 and ErFe2 samples have been determined from magnetic Compton scattering experiments performed at the KEK Accumulation Ring with 47.1 keV circularly polarized synchrotron radiation at temperatures 50-355 K. The polycrystalline samples were mounted in a cryostat and magnetized by an electromagnet producing a magnetic field of 0.5 T. The magnetic field was aligned parallel to the X-ray scattering vector and the scattering angle was fixed at 160 degrees . The good signal averaging associated with the use of an electromagnet facilitated the analysis of the magnetic Compton profiles of DeFe2 and ErFe2 in terms of a combination of rare-earth 4f, diffuse and iron 3d free-atom Compton profiles. The temperature dependence of the total spin moment mirrors the corresponding dependence of the rare-earth 4f moment. The rare-earth orbital moments have been deduced by combining the Compton data with bulk magnetization measurements.
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An automatic data-collection system has been implemented and installed on seven insertion-device beamlines and a bending-magnet beamline at the ESRF (European Synchrotron Radiation Facility) as part of the SPINE (Structural Proteomics In... more
An automatic data-collection system has been implemented and installed on seven insertion-device beamlines and a bending-magnet beamline at the ESRF (European Synchrotron Radiation Facility) as part of the SPINE (Structural Proteomics In Europe) development of an automated structure-determination pipeline. The system allows remote interaction with beamline-control systems and automatic sample mounting, alignment, characterization, data collection and processing. Reports of all actions taken are available for inspection via database modules and web services.
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The production of three-dimensional crystallographic structural information of macromolecules can now be thought of as a pipeline which is being streamlined at every stage from protein cloning, expression and purification, through... more
The production of three-dimensional crystallographic structural information of macromolecules can now be thought of as a pipeline which is being streamlined at every stage from protein cloning, expression and purification, through crystallisation to data collection and structure solution. Synchrotron X-ray beamlines are a key section of this pipeline as it is at these that the X-ray diffraction data that ultimately leads to the elucidation of macromolecular structures are collected. The burgeoning number of macromolecular crystallography (MX) beamlines available worldwide may be enhanced significantly with the automation of both their operation and of the experiments carried out on them. This paper reviews the current situation and provides a glimpse of how a MX beamline may look in the not too distant future.
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The structure of the manganese superoxide dismutase (Mn-SOD; DR1279) from Deinococcus radiodurans has been determined in two different crystal forms. Both crystal forms are monoclinic with space group P2(1). Form I has unit-cell... more
The structure of the manganese superoxide dismutase (Mn-SOD; DR1279) from Deinococcus radiodurans has been determined in two different crystal forms. Both crystal forms are monoclinic with space group P2(1). Form I has unit-cell parameters a = 44.28, b = 83.21, c = 59.52 angstroms, beta = 110.18 degrees and contains a homodimer in the asymmetric unit, with structure refinement (R = 16.8%, R(free) = 23.6%) carried out using data to d(min) = 2.2 angstroms. Form II has unit-cell parameters a = 43.57, b = 87.10, c = 116.42 angstroms, beta = 92.1 degrees and an asymmetric unit containing two Mn-SOD homodimers; structure refinement was effected to a resolution of 2.0 angstroms (R = 17.2%, R(free) = 22.3%). The resulting structures are compared with that of Mn-SOD from Escherichia coli, with which they are shown to be essentially isostructural.
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A new type of Compton spectrometer is introduced for use at energies of 100keV. Synchrotron radiation beam of a well-defined energy gradient is reflected on the sample by a cylindrically bent Laue-type monochromator, and the scattered... more
A new type of Compton spectrometer is introduced for use at energies of 100keV. Synchrotron radiation beam of a well-defined energy gradient is reflected on the sample by a cylindrically bent Laue-type monochromator, and the scattered radiation is analyzed by another bent Laue-type crystal. It is shown that nearly exact dispersion compensation is achieved over the entire energy spectrum. Due to the increased reflecting power of asymmetrically cut bent crystals the average count rate of Compton scattering is of the order of 104cps, while the momentum resolution of the spectrometer is 0.1a.u. or better. Results of the first test measurements are presented.