Enhanced energy range thermoelectrically cooled silicon X-ray detectors

Thermoelectrically cooled X-ray detectors are widely used in both portable and laboratory X-ray spectrometers. The most common detectors are fully depleted 500 μm devices behind a Be window to provide a vacuum tight enclosure. These provide good resolution and efficiency for characteristic X-rays from 2 keV to about 20 keV but a larger energy range is desirable. In many applications, one needs to measure elements with K lines below 2 keV and above 20 keV with good efficiency. Recent research at Amptek, Inc. has focused on enhancing both the upper and lower ends of this energy range. First, to improve efficiency at high energies, SDDs have been fabricated on 1 mm wafers. Second, to improve efficiency at low energies, windows made of 50 nm Si₃N₄ on a Si grid have been developed. Third, to improve resolution at low energies, electronic noise has been reduced by using a modified trapezoidal pulse shape with lower 1/f noise index. The performance of systems utilizing these enhancements will be presented.