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Title: Development of an on-demand beam pulsing system for Pixe-analysis of thick targets
Author: Armaghani, Mohammed A. S.
Awarding Body: Aston University
Current Institution: Aston University
Date of Award: 1985
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This work concerns the developnent of a proton irnuced X-ray emission (PIXEl analysis system and a multi-sample scattering chamber facility . The characteristics of the beam pulsing system and its counting rate capabilities were evaluated by observing the ion-induced X- ray pulsing operation. The characteristic X-rays were detected with a high resolution 5i(Li) detector ocoupled to a multi-channel analyser. The removal of the pile-up continuum by the use of the on-demand beam pulsing is clearly demonstrated in this work . This new on-demand pu1sing system with its counting rate capability of 25, 18 and 10 kPPS corresponding to 2, 4 am 8 used main amplifier time constant respectively enables thick targets to be analysed more readily. Reproducibility tests of the on-demand beam pulsing system operation were checked by repeated measurements of the system throughput curves, with and without beam pulsing . The reproducibility of the analysis performed using this system was also checked by repeated measurements of the intensity ratios from a number of standard binary alloys during the experimental work. A computer programme has been developed to evaluate the calculations of the X-ray yields from thick targets bombarded by protons, taking into account the secondary X-ray yield prproduction due to characteristic X- ray fluorescence from an element energetically higher than the absorption edge energy of the other element present in the target. This effect was studied on metallic binary alloys such aa Fe/Ni and Cr /Fe . The quantitative analysis of Fe/Ni and Cr/Fe alloy samples to determine their elemental composition taking into account the enhancement has been deIronstrated in this work. Furthermore , the usefulness of the Rutherford backscattering (R.B.S .) technique to obtain the depth profiles of the elements in the upper micron of the sample is discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physics ; Mathematics Atoms Molecules Nuclear physics Physics