Improving CdZnTe X-ray detector performance by cooling and rise time discrimination

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

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Monte Carlo simulation study of detector performance for X-ray baggage inspection system

10.1063/5.0017839 ◽

2020 ◽

Author(s):

Amit Kumar ◽

Anita Topkar

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Simulation Study ◽

Inspection System ◽

Detector Performance ◽

Monte Carlo Simulation Study ◽

X Ray

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Generation of Runaway Electrons and X-ray at a Microsecond Voltage Rise Time in Different Gases

2020 7th International Congress on Energy Fluxes and Radiation Effects (EFRE) ◽

10.1109/efre47760.2020.9242071 ◽

2020 ◽

Author(s):

Alexander Burachenko ◽

Victor Tarasenko ◽

Evgenii Baksht

Keyword(s):

Rise Time ◽

Runaway Electrons ◽

Voltage Rise ◽

X Ray ◽

Different Gases

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Observations of X-rays from Laboratory Sparks in Air at Atmospheric Pressure under Negative Switching Impulse Voltages

Atmosphere ◽

10.3390/atmos10040169 ◽

2019 ◽

Vol 10 (4) ◽

pp. 169 ◽

Cited By ~ 1

Author(s):

Mahbubur Rahman ◽

Pasan Hettiarachchi ◽

Vernon Cooray ◽

Joseph Dwyer ◽

Vladimir Rakov ◽

...

Keyword(s):

Rise Time ◽

Atmospheric Pressure ◽

Opposite Polarity ◽

X Rays ◽

X Ray ◽

Impulse Voltage ◽

First Time ◽

Switching Impulses ◽

Low Rate

We present observations of X-rays from laboratory sparks created in the air at atmospheric pressure by applying an impulse voltage with long (250 µs) rise-time. X-ray production in 35 and 46 cm gaps for three different electrode configurations was studied. The results demonstrate, for the first time, the production of X-rays in gaps subjected to switching impulses. The low rate of rise of the voltage in switching impulses does not significantly reduce the production of X-rays. Additionally, the timing of the X-ray occurrence suggests the possibility that the mechanism of X-ray production by sparks is related to the collision of streamers of opposite polarity.

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Study of Detector-Grade CdMnTe:In Crystals Obtained by a Multi-Step Post-Growth Annealing Method

Crystals ◽

10.3390/cryst8100387 ◽

2018 ◽

Vol 8 (10) ◽

pp. 387 ◽

Cited By ~ 2

Author(s):

Pengfei Yu ◽

Yongren Chen ◽

Wei Li ◽

Wenfei Liu ◽

Bin Liu ◽

...

Keyword(s):

Annealing Temperature ◽

Crystal Quality ◽

High Resistivity ◽

Detector Performance ◽

Rocking Curve ◽

X Ray ◽

Annealing Step ◽

Subsequent Step ◽

Te Inclusions ◽

Annealing Method

A multi-step annealing method was successfully applied to inclusions reduction and resistivity improvement of CdMnTe:In (CMT:In) single crystals with high resistivity, including a Cd atmosphere annealing step followed by a Te atmosphere annealing step. After the Cd atmosphere annealing step, the density of Te inclusions was reduced distinctly, and it could be also decreased in the subsequent step of re-annealing under Te atmosphere. Both the resistivity and IR transmittance decreased notably after Cd atmosphere annealing, whereas they increased tremendously after re-annealing under a Te atmosphere. The reduction of full-width at-half-maximum (FWHM) and the increase of the intensity of the X-ray rocking curve indicated an improvement of the crystal quality. Meanwhile, after Cd atmosphere annealing, the increase of the intensity of the (D0,X) peak and the disappearance of the (A0,X) peak in photoluminescence (PL) measurements suggested further that the crystal quality was improved. The detector performance was enhanced obviously after annealing. The higher the annealing temperature, the better the performance was. The detector fabricated by CMT:In slice (Cd atmosphere annealing at 1073 K for 240 h and Te atmosphere re-annealing at 773 K for 120 h) with 9.43% energy resolution and 1.25 × 10−3 cm2/V μτ value had the best detector performance.

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Defects in Silver-Doped Mercuric Iodide Crystals and their Effect on X-Ray and Gamma-Ray Detector Performance

MRS Proceedings ◽

10.1557/proc-302-103 ◽

1993 ◽

Vol 302 ◽

Cited By ~ 1

Author(s):

R. B. James ◽

X. J. Bao ◽

T. E. Schlesinger ◽

A. Y. Cheng ◽

V. M. Gerrish

Keyword(s):

Gamma Ray ◽

Electrical Contacts ◽

Source Material ◽

Broad Emission Band ◽

Interfacial Region ◽

Mercuric Iodide ◽

Detector Performance ◽

X Ray ◽

Silver Silver ◽

Gamma Ray Detector

ABSTRACTThe processing steps associated with purification of source material, crystal growth, and attachment of electrical contacts can introduce defects into mercuric iodide (HgI2) that degrade the performance of detectors. We have employed low-temperature photoluminescence (PL) spectroscopy to study radiative recombination centers in the interfacial region between a thin semitransparent film of silver and mercuric iodide. The Ag film was found to introduce a new broad emission band centered at 5490 Å in the photoluminescence spectrum of HgI2. This PL feature can be used as a signature to identify the existence of Ag as a contaminant in HgI2 crystals and detectors. Experiments were also conducted on mercuric iodide surfaces that had been doped with silver, and the results showed that Ag is a rapid diffuser in bulk HgI2. Detectors with silver electrodes were also fabricated and tested using an americium-241 gamma-ray source. Large increases in the leakage currents were observed for the Ag-doped HgI2 devices, indicated that Ag impurities are electrically active in HgI2. These measurements show that silver is unacceptable as an electrode material for mercuric iodide x-ray and gamma-ray detector applications. In addition, they reveal that caution must be taken during handling of mercuric iodide source material, crystals, and detectors to avoid contact with silver, silver compounds, or with any material that contains silver as a contaminant.

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