A low-profile monolithic multi-element Ge detector for X-ray fluorescence applications

Derbyshire, G.E.; Cheung, Kan-Cheung; Sangsingkeow, P.; Hasnain, S.S.

doi:10.1107/s0909049598017695

Cited by 39 publications

(25 citation statements)

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“…The SrAl 2 O 4 :Eu,Dy phosphors could not be measured in transmission mode because of the low dopant concentration and the relatively strong x-ray absorption of the SrAl 2 O 4 host matrix. The x-ray fluorescence yield was detected with a 9-element monolithic Ge detector 19 . Determination of the edge position, background subtraction and normalization of the calibrated raw XANES data was performed using Athena 20 .…”

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confidence: 99%

Luminescence and x-ray absorption measurements of persistent SrAl2O4:Eu,Dy powders: Evidence for valence state changes

et al. 2011

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The development of new efficient afterglow phosphors is currently hampered by a limited understanding of the persistent luminescence mechanism. Radioluminescence and x-ray absorption measurements on the persistent phosphor SrAl 2 O 4 :Eu,Dy were combined to reveal possible valence state changes for the rare earth (co)dopants. Traps in the phosphor material are quickly filled when exposing thermally emptied SrAl 2 O 4 :Eu,Dy powder to x-rays. On the same time scale, a partial oxidation of Eu 2+ to Eu 3+ is observed by XANES (x-ray absorption near-edge spectroscopy), while for the trivalent dysprosium the valence state remains unchanged. The impact of these observations on the recently proposed models for persistent luminescence is discussed.

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confidence: 99%

Luminescence and x-ray absorption measurements of persistent SrAl2O4:Eu,Dy powders: Evidence for valence state changes

et al. 2011

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“…Cu K-edge X-ray absorption data were collected in fluorescence mode using an energy-resolving four-element monolithic germanium C-TRAIN-4 detector (Ortec) (Derbyshire et al, 1999). A silicon (111) Views of the microspectrophotometer as installed on SRS beamline 10.…”

Section: Optical Xas and MX Data Collection From Axnir Crystalsmentioning

confidence: 99%

“…The end-station of the beamline is composed of a MAR desktop beamline (DTB) with cryogenic sample changer, with a MARMosaic 225 CCD detector for recording diffraction data and an Ortec C-TRAIN-04 detector for measuring XAS data (Derbyshire et al, 1999). Here we describe an extension to these capabilities through the incorporation of a singlecrystal microspectrophotometer into the goniometry, thus allowing optical spectra to be collected in situ and in parallel with X-ray diffraction and high-quality XAS data.…”

Section: Introductionmentioning

confidence: 99%

On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states

Ellis

Buffey

Hough

et al. 2008

J Synchrotron Radiat

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X-ray-induced redox changes can lead to incorrect assignments of the functional states of metals in metalloprotein crystals. The need for on-line monitoring of the status of metal ions (and other chromophores) during protein crystallography experiments is of growing importance with the use of intense synchrotron X-ray beams. Significant efforts are therefore being made worldwide to combine different spectroscopies in parallel with X-ray crystallographic data collection. Here the implementation and utilization of optical and X-ray absorption spectroscopies on the modern macromolecular crystallography (MX) beamline 10, at the SRS, Daresbury Laboratory, is described. This beamline is equipped with a dedicated monolithic energy-dispersive X-ray fluorescence detector, allowing X-ray absorption spectroscopy (XAS) measurements to be made in situ on the same crystal used to record the diffraction data. In addition, an optical microspectrophotometer has been incorporated on the beamline, thus facilitating combined MX, XAS and optical spectroscopic measurements. By uniting these techniques it is also possible to monitor the status of optically active and optically silent metal centres present in a crystal at the same time. This unique capability has been applied to observe the results of crystallographic data collection on crystals of nitrite reductase from Alcaligenes xylosoxidans, which contains both type-1 and type-2 Cu centres. It is found that the type-1 Cu centre photoreduces quickly, resulting in the loss of the 595 nm peak in the optical spectrum, while the type-2 Cu centre remains in the oxidized state over a much longer time period, for which independent confirmation is provided by XAS data as this centre has an optical spectrum which is barely detectable using microspectrophotometry. This example clearly demonstrates the importance of using two on-line methods, spectroscopy and XAS, for identifying well defined redox states of metalloproteins during crystallographic data collection.

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“…All measurements were performed in a standard cell [14] in the fluorescence mode, using a C-TRAIN detector with XSPRESS processing electronics [15]. The measurements were carried out on the as-deposited, fully hydrogenated and dehydrogenated films.…”

Section: Data Collectionmentioning

confidence: 99%

Structure of the Mg2Ni switchable mirror: an EXAFS investigation

Vece

Eerden

Grandjean

et al. 2005

Materials Chemistry and Physics

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Hydrogen intercalation changes both the structure and the optical properties of Mg 2 Ni thin films. The structure of evaporated thin films was investigated in the as-deposited, hydrogenated and dehydrogenated states with extended X-ray absorption fine structure (EXAFS) and X-ray diffraction (XRD). The partially crystalline virgin film becomes completely amorphous upon hydrogenation. After removal of the intercalated hydrogen the film remains amorphous. Hydrogen was detected in different concentrations in the virgin, hydrogenated and dehydrogenated films. Hydrogen loading was confirmed both by a shift of the nickel absorption edge and an increase of the hydrogen content. The intercalated hydrogen in the completely loaded film is located around the nickel atom with a coordination close to four.

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A low-profile monolithic multi-element Ge detector for X-ray fluorescence applications

Cited by 39 publications

References 0 publications

Luminescence and x-ray absorption measurements of persistent SrAl2O4:Eu,Dy powders: Evidence for valence state changes

Luminescence and x-ray absorption measurements of persistent SrAl2O4:Eu,Dy powders: Evidence for valence state changes

On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states

Structure of the Mg2Ni switchable mirror: an EXAFS investigation

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