Performance of Radiation Detectors with the Pulse-Reset Readout Based on PentaFET

Abstract

X-ray nano-analytical tools impose stringent requirements on low-energy resolution and long-term peak stability of radiation detection systems. The front contact interface, noise performance of a read-out FET, dielectric properties of the feedback capacitor and baseline restoration algorithm play crucial roles in meeting these requirements. An electronic reset method based on PentaFET is well established in spectrometry with Si(Li) detectors. This paper shows how the same method offers distinct advantages for silicon drift chambers (SDD) when compared with other readout methods employing various continuous discharge mechanisms. While the resolution at low X-ray energies for the pn-junction SDDs is currently limited by charge collection, the quasi-Schottky junction Si(Li) detectors still offer the best prospects for low energy X-ray spectrometry. An electronic noise as low as 3.34e (30.39 eV) and 4.03e (36.11 eV) FWHM have been achieved with 10 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 30 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area Si(Li) detectors coupled to the PentaFETtrade with no compromise on the low energy tailing. A carbon resolution of 49.95 eV has been measured with our new INCAPentaFET-x3trade 30 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> detector as a part of the complete energy dispersive spectrometer mounted on the scanning electron microscope (SEM).