An unusual case of intussusception

Jones, Clifford

doi:10.1002/bjs.18003413521

Cited by 2 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8 The filters used were: Al and Cu, Gammex 115A and 116 HVL attenuator sets, respectively; Mo, Goodfellow Cambridge Ltd, 99.9% purity, temperannealed; Au, Advent Research Materials Ltd, 99.99% purity, temper -as rolled. The importance of using such high-quality/-purity filter materials in the present case has been investigated by, for example, Hü bner (1958), Jones (1961) and Archer et al (1988). 9 Small corrections (angular offsets) were made on the basis of peak-shape fitting to establish the true 0 position for each scan.…”

Section: Pink Beammentioning

confidence: 99%

Estimating the absolute flux distribution for a synchrotron X-ray beam using ionization-chamber measurements with various filters

Stevenson

Lillo

2017

J Synchrotron Radiat

View full text Add to dashboard Cite

It is shown that an extensive set of accurate ionization-chamber measurements with a primary polychromatic synchrotron X-ray beam transmitted through various filter combinations/thicknesses can be used to quite effectively estimate the absolute flux distribution. The basic technique is simple but the `inversion' of the raw data to extract the flux distribution is a fundamentally ill-posed problem. It is demonstrated, using data collected at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron, that the absolute flux can be quickly and reliably estimated if a suitable choice of filters is made. Results are presented as a function of the magnetic field (from 1.40 to 4.00 T) of the superconducting multi-pole wiggler insertion device installed at IMBL. A non-linear least-squares refinement of the data is used to estimate the incident flux distribution and then comparison is made with calculations from the programs SPECTRA, XOP and spec.exe. The technique described is important not only in estimating flux itself but also for a variety of other, derived, X-ray properties such as beam quality, power density and absorbed-dose rate. The applicability of the technique with a monochromatic X-ray beam for which there is significant harmonic contamination is also demonstrated. Whilst absolute results can also be derived in this monochromatic beam case, relative (integrated) flux values are sufficient for our primary aim of establishing reliable determinations of the percentages of the various harmonic components.

show abstract

Section: Pink Beammentioning

confidence: 99%