Optimisation of X-ray micro-tomography for the low-dose analysis of highly-dosed gels

An X-ray micro-tomography system has been designed that is optimised for low dose imaging of radiation sensitive polymer gels. The scanner is based on a third-generation cone-beam X-ray CT scanner. A mini-focus X-ray source (Oxford XTF5011 or an Oxford series 1500) is used in conjunction with a 100mm diameter X-ray image intensifier (Hamamatsu C7336). The sample may be rotated and moved perpendicular to the beam axis. A schematic view of the system is shown in figure 1. The XTF5011 X-ray source has a focal spot diameter of 100μm, has a silver target, and is operated at 50 kVp, 0.5 mA and the series 1500 source has a focal spot diameter of 33 μm, has a tungsten target, and is operated at 80 kVp, 0.25 mA. The polychromatic source from the XTF5011 X-ray source is filtered using 2 mm of aluminium and 50 μm of palladium giving a “quasi-monochromatic” spectrum centred about the 22 keV silver Kα characteristic peak. Institute of Physics Publishing Journal of Physics: Conference Series 3 (2004) 257–260 doi:10.1088/1742-6596/3/1/041 Third International Conference on Radiotherapy Gel Dosimetry