Improvement in the low energy collection efficiency of Si(Li) X-ray detectors

Cox, Christopher E.; Fischer, Daniel A.; Schwarz, Willi; Song, Yongwei

doi:10.1016/j.nimb.2005.07.091

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…Commonly, all Monte Carlo codes give computed values that deviate significantly (> 10 %) from the experimental efficiency data [1,3,7,8,9,10], due to uncertainties associated to the values of the detector parameters supplied by manufacturer [7,12] and/or incomplete charge collection in the crystal [5,13]. The incomplete charge collection was overcome solving the Poisson differential equation for the potential and electric field inside the detector crystal [2,5,6,10]. But this procedure seems not sufficient to completely match the experimental and simulated values of the efficiency.…”

Section: Resultsmentioning

confidence: 99%

Si(Li) detector parameters optimization using efficiency calibration

Haifa¹,

Omrane²,

Trabelsi³

2007

AIP Conference Proceedings

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detector for the hard x-ray microprobe at ID22 (ESRF) Rev. Sci. Instrum. 77, 063705 (2006); Abstract. The efficiency of a Si(Li) detector was determined experimentally and adequately simulated with the GEANT4 code in the energy range from 5 to 27 keV. The point-like sources used were 55 Fe, 65 Zn, 85 Sr, 109 Cd and 241 Am. For simulation of the detector response we have used a recent version of GEANT4 8.0 (Released 10 February 2006). In this version, all needed electro-magnetic processes are considered, essentially Compton scattering, photo-electric effect, Raleigh effect, multiple scattering, fluorescence and Auger effect and ionization. The detector was firstly modeled using its technical dimensions supplied by the manufacturer. Then these dimensions were optimized in order to reproduce the experimental efficiency. An agreement better than 98 % for almost all the energy lines (5 to 27 keV) between experimental and simulated efficiency values was obtained by adjusting some detector parameters. Those optimized parameters are the front dead layer of the crystal which is increased by 1.3 µm and the crystal-to-window distance which is increased by 0.7 mm. Those results indicated that our simulation code is operational for a reliable interpolation and extrapolation of experimental efficiency data and can be accurately used for simulation of X-ray fluorescence spectrum acquisition.

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Section: Resultsmentioning

confidence: 99%

Si(Li) detector parameters optimization using efficiency calibration

Haifa¹,

Omrane²,

Trabelsi³

2007

AIP Conference Proceedings

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“…In addition, as we mentioned in the introduction, the resolution at low energies is affected by both the electronic noise and incomplete charge collection, whereas at MnKα, the former plays only a minor role. The fabrication processes of Si(Li) X-ray detectors with ultra-shallow entrance windows intended for applications at a sub-1 keV range have been reviewed in [19]. The charge generated in crystals by the incoming photons was read out by a DC coupled charge-sensitive preamplifier.…”

Section: Resultsmentioning

confidence: 99%

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

Polushkin

Sharp

2006

2006 IEEE Nuclear Science Symposium Conference Record

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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 2 and 30 mm 2 area Si(Li) detectors coupled to the PentaFET TM with no compromise on the low energy tailing. A carbon resolution of 49.95 eV has been measured with our new INCAPentaFET-x3 TM 30 mm 2 detector as a part of the complete energy dispersive spectrometer mounted on the scanning electron microscope (SEM).

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“…In the conventional detectors, the p-contacts are used as windows for lowenergy X-rays [41][42][43]. Therefore, such detectors adopted Schottky barrier contacts to minimize the p-side insensitive layers while suppressing bulk leakage currents.…”

Section: Driftmentioning

confidence: 99%

Developing a mass-production model of large-area Si(Li) detectors with high operating temperatures

Kozai

Fuke

Yamada

et al. 2019

Nuclear Instruments and Methods in Physics Research Section A:

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This study presents a fabrication process for lithium-drifted silicon (Si(Li)) detectors that, compared to previous methods, allows for mass production at a higher yield, while providing a large sensitive area and low leakage currents at relatively high temperatures. This design, developed for the unique requirements of the General Antiparticle Spectrometer (GAPS) experiment, has an overall diameter of 10 cm, with ∼9 cm of active area segmented into 8 readout strips, and an overall thickness of 2.5 mm, with 2.2 mm ( 90%) sensitive thickness. An energy resolution 4 keV full-width at half-maximum (FWHM) for 20−100 keV X-rays is required at the operating temperature ∼ − 40 • C, which is far above the liquid nitrogen temperatures conventionally used to achieve fine energy resolution. High-yield production is also required for GAPS, which consists of 1000 detectors. Our specially-developed Si crystal and custom methods of Li evaporation, diffusion and drifting allow for a thick, large-area and uniform sensitive layer. We find that retaining a thin undrifted layer on the p-side of the detector drastically reduces the leakage current, which is a dominant component of the energy resolution at these temperatures. A guard-ring structure and optimal etching of the detec- tor surface are also confirmed to suppress the leakage current. We report on the mass production of these detectors that is ongoing now, and demonstrate it is capable of delivering a high yield of ∼90%.We present here a high-yield mass production process for lithium-drifted silicon (Si(Li)) detectors that meet the unique requirements of the General Antiparticle Spectrometer (GAPS) experiment. GAPS is a balloon-borne experiment that aims to survey low-energy (<0.25 GeV/n) cosmic-ray antinuclei for the first time, by adopting a novel detection concept based on the physics of exotic atoms [1][2][3][4]. Low-energy cosmic-ray antinuclei, especially antideuterons, are predicted to be distinctive probes for the dark matter annihilation or decay occurring in the Galactic halo [1,[5][6][7][8][9]. Precise measurement of the low-energy antiproton spectra will also provide crucial information on the source and propagation mechanisms of cosmic rays [10][11][12][13]. GAPS sensitivities to antideuterons and antiprotons are discussed in [14] and [13], and capabilities for antihelium detection are being evaluated. The first flight of GAPS via a NASA Antarctic long duration balloon is planned for late 2021.GAPS is comprised of a 1.6 m W × 1.6 m D × 1.0 m H tracker made of Si(Li) detectors surrounded by a time-of-flight (TOF) system made of plastic scintillator paddles. A low-energy antinucleus triggered by the TOF is slowed and captured by the Si(Li) detector array, forming an excited exotic atom with a silicon nucleus. It immediately decays, radiating de-excitation X-rays of characteristic energies. The antinucleus then annihilates with the silicon nucleus, producing pions and protons with a multiplicity that scales with the incident antinucleus mass. The surrounding Si(Li)...

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Improvement in the low energy collection efficiency of Si(Li) X-ray detectors

Cited by 11 publications

References 15 publications

Si(Li) detector parameters optimization using efficiency calibration

Si(Li) detector parameters optimization using efficiency calibration

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

Developing a mass-production model of large-area Si(Li) detectors with high operating temperatures

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