High energy resolution pixel detectors based on boron oxide vertical Bridgman grown CdZnTe crystals

Gohil

Journal of Applied Physics

et al. 2016

A prototype 200 μm diameter Al0.52In0.48P p+-i-n+ mesa photodiode (2 μm i-layer) was characterised at temperatures from 100 °C to −20 °C for the development of a temperature tolerant photon counting X-ray spectrometer. At each temperature, X-ray spectra were accumulated with the AlInP detector reverse biased at 0 V, 5 V, 10 V, and 15 V and using different shaping times. The detector was illuminated by an 55Fe radioisotope X-ray source. The best energy resolution, as quantified by the full width at half maximum (FWHM) at 5.9 keV, was observed at 15 V for all the temperatures studied; at 100 °C, a FWHM of 1.57 keV was achieved, and this value improved to 770 eV FWHM at −20 °C. System noise analysis was also carried out, and the different noise contributions were computed as functions of temperature. The results are the first demonstration of AlInP's suitability for photon counting X-ray spectroscopy at temperatures other than ≈20 °C.

Section: Introductionmentioning

confidence: 99%

Temperature study of Al0.52In0.48P detector photon counting X-ray spectrometer

Gohil

Journal of Applied Physics

et al. 2016

“…CdTe and CdZnTe detectors have been widely developed for room temperature X-ray spectroscopy. For example, Zappettini et al [8] demonstrated CdZnTe detectors with an energy resolution at 59.5 keV of 2.5 keV using low-noise application specific integrated circuit (ASIC) readout electronics. Abbene et al [9] reported a CdZnTe structure showing energy resolutions of 3.8% (2.26 keV) and 3.2% (3.91 keV) at 59.5 keV and 122.1 keV, respectively, at low count rate.…”

mentioning

confidence: 99%

Temperature characterisation of spectroscopic InGaP X-ray photodiodes

Nuclear Instruments and Methods in Physics Research Section A:

Krysa

et al. 2018

In this paper for the first time, an InGaP photodiode was used in a high temperature tolerant X-ray spectrometer. The use of InGaP in X-ray spectrometers shows a significant advance within this field allowing operation up to 100 °C. Such results are particularly important since GaP and InP (the InGaP binary parent compounds) are not spectroscopic even at room temperature. The best energy resolution (smallest FWHM) at 5.9 keV for the InGaP spectrometer was 1.27 keV at 100 °C and 770 eV at 20 °C, when the detector was reverse biased at 5 V. The observed FWHM were higher than the expected statistically limited energy resolutions indicating that other sources of noise contributed to the FWHM broadening. The spectrometer's Si preamplifier electronics was the limiting factor for the FWHM rather than the InGaP photodiode itself. The InGaP electron-hole pair creation energy (εInGaP) was experimentally measured across the temperature range 100 °C to 20 °C. εInGaP was 4.94 eV ± 0.06 eV at 20 °C.

InGaP (GaInP) mesa p-i-n photodiodes for X-ray photon counting spectroscopy

Krysa

et al. 2017

Sci Rep

In this paper, for the first time an InGaP (GaInP) photon counting X-ray photodiode has been developed and shown to be suitable for photon counting X-ray spectroscopy when coupled to a low-noise charge-sensitive preamplifier. The characterisation of two randomly selected 200 μm diameter and two randomly selected 400 μm diameter In0.5Ga0.5P p+-i-n+ mesa photodiodes is reported; the i-layer of the p+-i-n+ structure was 5 μm thick. At room temperature, and under illumination from an 55Fe radioisotope X-ray source, X-ray spectra were accumulated; the best spectrometer energy resolution (FWHM) achieved at 5.9 keV was 900 eV for the 200 μm In0.5Ga0.5P diameter devices at reverse biases above 5 V. System noise analysis was also carried out and the different noise contributions were computed.