Greg Roach

Characterisation of coal and minerals using Compton profile analysis

Abstract There is considerable interest in the coal and mineral industries in the direct on-stream measurement of material composition. To the knowledge of the authors, the application of Compton profile analysis (CPA) has not been previously reported in this area. A Compton profile analyser has been constructed and tested in two applications, namely the determination of ash in synthetic coal samples and the simultaneous measurement of the solids loading fraction of slurries along with the determination of their heavy metal content via XRF. For the coal samples, the error for ash determination was 0.58 wt.% (1 std), compared with 1.4 wt.% for the industry-standard dual energy transmission technique. For the slurry solids loading measurements, the error was 0.3 wt.%. In this application, the key advantages of the CPA method are that the solids loading is determined using the same source and detector used for the XRF measurements and that the two measurements are performed over the same sample volume.

Beam Stop for Electron Accelerator Beam Characterisation

Electron linear accelerator applications involving the generation of hard X-rays frequently require accurate knowledge of the electron beam parameters. We developed a beam stop device which houses a tungsten Bremsstrahlung target and enables the electron beam current, energy and position to be monitored.

Beam stop for electron accelerator beam characterisation

Electron linear accelerator applications involving the generation of hard X-rays frequently require accurate knowledge of the electron beam parameters. We developed a beam stop device which houses a tungsten Bremsstrahlung target and enables the electron beam current, energy and position to be monitored. The beam stop consisted of four plates. The first was a removable aluminium (Al) transmission plate. Then followed the tungsten target. Behind the target there were four Al quadrant plates for beam position measurement. The last plate was a thick Al back-stop block. Currents from the four quadrants and the back-stop were measured and the beam lateral position, energy and current were calculated. The beam stop device was optimised using Monte-Carlo simulation, manufactured (including custom-made electronics and software) in our laboratory and tested at the ARPANSA (Australian Radiation Protection and Nuclear Safety Agency) linear accelerator in Melbourne. The electron beam energy was determined with a precision of 60 keV at beam energies between 11 and 21 MeV and the lateral beam position was controlled with a precision of 200 mum. The relative changes of the beam current were monitored as well.