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Record W2021743093 · doi:10.1118/1.2244646

Po‐Thur Eve General‐19: Energy dispersive x‐ray diffraction system: Analysis of noise at low momentum transfer arguments

2006· article· en· W2021743093 on OpenAlexaff
R. J. LeClair, Y Wang, P. Zhao

Bibliographic record

VenueMedical Physics · 2006
Typearticle
Languageen
FieldMedicine
TopicRadiation Dose and Imaging
Canadian institutionsLaurentian University
Fundersnot available
KeywordsDiffractionOpticsPinhole (optics)PhysicsBeam (structure)ScatteringMomentum transferAperture (computer memory)Photon

Abstract

fetched live from OpenAlex

An energy dispersive x‐ray diffraction system has been built to measure the diffraction signals of breast tissue. The diffraction signals are a function of the momentum transfer argument, x=(E/hc)sin(θ/2), where E = photon energy and θ = scatter angle. The current system has noise problems for signals measured at x < 1.3 nm−1 where it is anticipated that most of the contrast exist for diagnosing normal breast tissue versus cancerous tissue. For a 5 mm thick 5 mm diameter water sample, the scatter signals at low x obtained at 9° with a 3 mm diameter 50 kV beam are about 70% higher than what are to be expected. Values at higher x values are however in good agreement with those in the literature. In this work we measured the scattered field from the pinhole since it could contribute to the large signals at low x values. The scattered count rates were measured at angles of 2 to 15 degrees in the usual way. For smaller angles including zero we used a 1.5 mm by 1.5 mm beam stopper centered at the bottom of the pinhole. A 100 μm diameter W aperture was placed above the detector and the field was sampled at various locations in the shadow of the beam stopper. The results suggest that the scatter from the pinhole could increase the diffraction signals at low x by 6%. Based on these findings we intend to revisit our measurement of the incident spectrum and the multiple scatter.

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.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.002
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.012
Threshold uncertainty score0.040

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0020.002
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0020.002
Science and technology studies0.0010.001
Scholarly communication0.0020.001
Open science0.0020.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0120.002

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 head0.006
GPT teacher head0.237
Teacher spread0.231 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2006
Admission routes1
Has abstractyes

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