Experimental characterization of alpha spectrometer for optimization of operational parameters affecting energy resolution and detection efficiency

The operational parameters of an alpha spectrometer equipped with a planar silicon semiconductor detector were characterized by measuring a mixed alpha source. The full width at half maximum (FWHM) decreased with increasing conversion gain (CG) and sample-to-detector distance (SDD) and was constant beyond an SDD of 21 mm. Although the FWHM was minimum at 4096 CG, peak-shape analysis showed that 1024 CG and 2048 CG are more appropriate than 4096 CG for alpha spectrum analysis. In practical measurement with SDD less than 5 mm, a sample thickness difference of 1 mm caused a relative error in detection efficiency of 11 %.