Cadmium telluride (CdTe) is a semiconducting material for gamma-ray spectroscopy, which has several interesting properties such as high relative efficiency and low cost, and it is operable at room temperature. A problem though is trapping of the charge carriers. The effects of trapping are degraded spectroscopic performance, which however, can be improved by applying adequate pulse-processing techniques such as the pulse shape correction method investigated here.
This diploma work comprises both experimental studies and studies based on simulations of a planar CdTe detector with a thickness of 3 mm and an area of 5 mm x 5 mm. In the experimental part of the work, an 8 bit and 100 MS/s Analogue-to-Digital Converter (ADC) was used. The experimental results were used to validate the simulation software developed in this work. This software emulated experimental setups with various digital resolution and sampling rate. As quality measures for the analysis, the peak-to-Compton ratio, the peak-to-total ratio and the energy resolution, in terms of the Full Width at Half Maximum (FWHM), were used.
The experimental results for the peak-to-Compton and the peak-to-total ratios were about 0.7 and 0.08, respectively and the FWHM was 9.4 % at 662 keV. After correction using the pulse shape correction method the corresponding results were 1.1, 0.2 and 8.3 %, respectively. For the simulations of a 14 bit and 100 MS/s ADC, the uncorrected results were 0.8, 0.03, and 3.5 % at 662 keV, respectively, while the corrected results were 1.9, 0.1, and 3.4 %, respectively