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Record W2042516064 · doi:10.1107/s0909049508030859

Selected techniques in diamond anvil cell crystallography: centring samples using X-ray transmission and rocking powder samples to improve X-ray diffraction image quality

2008· article· en· W2042516064 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueJournal of Synchrotron Radiation · 2008
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicHigh-pressure geophysics and materials
Canadian institutionsUniversity of Ottawa
Fundersnot available
KeywordsCentringDiffractionOpticsX-rayBeam (structure)Rotation (mathematics)Collimated lightSample (material)X-ray crystallographyCalibrationMaterials scienceDetectorSynchrotronDiamond anvil cellPhysicsGeometryMathematicsLaser

Abstract

fetched live from OpenAlex

The distinct X-ray transmission profile obtained by scanning a sample in a diamond anvil cell across a collimated X-ray beam is used to monitor sample displacement brought about by rotation. This measured displacement can in turn be used to calculate, and subsequently correct, the sample position with respect to a centre of rotation. This centring method differs from others also based on transmission in that it does not require a 180 degrees sample rotation, nor does it require prior positioning of the rotation axis in the path of the X-ray beam. After a full description of the method, an example is presented together with an extended record of use to evaluate the method in a practical setting. The practice and benefits of rocking polycrystalline samples during X-ray exposure have also been quantitatively examined. Changing the orientation of the sample grains with respect to the incident beam yields the expected result of a more homogeneous intensity distribution along Debye rings. Interestingly, by limiting the amount of time large grains assume a particular orientation, rocking brings about the added effect of significantly reducing detector saturation. Sample rocking yields more reliable relative intensities, a more appropriate line shape and narrower line width. Data are presented for a calibration standard at ambient pressure as well as a research sample at high pressure.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.856
Threshold uncertainty score0.563

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.015
GPT teacher head0.241
Teacher spread0.226 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it