Characterisation of a GaAs(Cr) Medipix2 hybrid pixel detector

Tlustos, L.; Shelkov, G.A.; Толбанов, О. П.

doi:10.1016/j.nima.2010.06.137

Cited by 37 publications

(34 citation statements)

References 6 publications

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“…The outermost 20 columns on the right chip edge were found to be defective in the digital chip test and thus were masked. Besides these columns, in total only 52 pixels were found to be nonfunctional, which corresponds to a bonding yield of more than 99.9% and shows the improvement in processing and flip-chip bonding compared to previous measurements using the same material [39]. The higher counting and partially saturated pixels in the outermost regions of the chip reflect the higher leakage current flowing along the sensor edges due to the absence of a guard ring.…”

Section: A Detector Characterizationmentioning

confidence: 61%

Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor

Hamann

Koenig

Zubér

et al. 2015

IEEE Trans. Med. Imaging

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High resistivity gallium arsenide is considered a suitable sensor material for spectroscopic X-ray imaging detectors. These sensors typically have thicknesses between a few hundred μm and 1 mm to ensure a high photon detection efficiency. However, for small pixel sizes down to several tens of μm, an effect called charge sharing reduces a detector's spectroscopic performance. The recently developed Medipix3RX readout chip overcomes this limitation by implementing a charge summing circuit, which allows the reconstruction of the full energy information of a photon interaction in a single pixel. In this work, we present the characterization of the first Medipix3RX detector assembly with a 500 μm thick high resistivity, chromium compensated gallium arsenide sensor. We analyze its properties and demonstrate the functionality of the charge summing mode by means of energy response functions recorded at a synchrotron. Furthermore, the imaging properties of the detector, in terms of its modulation transfer functions and signal-to-noise ratios, are investigated. After more than one decade of attempts to establish gallium arsenide as a sensor material for photon counting detectors, our results represent a breakthrough in obtaining detector-grade material. The sensor we introduce is therefore suitable for high resolution X-ray imaging applications.

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Section: A Detector Characterizationmentioning

confidence: 61%

Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor

Hamann

Koenig

Zubér

et al. 2015

IEEE Trans. Med. Imaging

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“…Therefore, materials showing higher atomic numbers, like CdTe (Z=48, 52) or Ge (Z=32) have to be used. As shown previously [1], semi-insulating (SI), chromium (Cr) compensated GaAs (Z=31, 33) also proves to be a good alternative as sensor material for detection of X-rays in the mid-energy range up to ~60-80 keV, closing the gap between the low-absorbing, high quality Si and the high absorbing, lower quality CdTe.…”

Section: Introductionmentioning

confidence: 70%

Characterization of photon counting pixel detectors based on semi-insulating GaAs sensor material

Hamann

Cecilia

Zwerger

et al. 2013

J. Phys.: Conf. Ser.

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“…As discussed earlier [1][2][3][4], gallium arsenide compensated with chromium is a promising material for semiconductor detectors with X-ray photon energies ranging from 15 to 60 keV. The results of investigations on the variations in the pulse height distribution with the electrophysical characteristics of the detector material and in the output signal (photocurrent and count rate) with the X-ray intensity and bias voltage are presented.…”

Section: Contentsmentioning

confidence: 97%

Chromium-compensated GaAs detector material and sensors

Budnitsky¹,

Tyazhev²,

Novikov³

et al. 2014

J. Inst.

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Results obtained from numerical calculations of and experimental studies on the pulse height distribution inherent in ionizing radiation gallium arsenide sensors as a function of the design features of the devices and electrophysical characteristics of the detector material are presented. It is shown that the pulse height distribution is defined by the distribution pattern of the nonequilibrium charge carrier lifetime and by the electric field profile in the bulk of the sensor. Investigations on the detector sensitivity to X-ray energies in the range between 40 and 150 keV were performed. The sensor polarization was found to produce only a marginal effect compensated by an increase in the bias voltage. Prototype pixel sensors measuring 256 × 256 and 512 × 768 pixels with a 55 µm pitch and a 500 µm thick sensitive layer were produced. The dependence of the photocurrent and count rate on the X-ray radiation intensity and bias voltage applied to the sensor was examined. In the 40-80 keV energy range, the maximum count rate amounted to 800 kHz/pixel for a negative sensor bias voltage of 800 V. The sensors are demonstrated to provide spatial resolution varying with the pixel pitch and to enable high-quality X-ray images to be obtained.

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Characterisation of a GaAs(Cr) Medipix2 hybrid pixel detector

Cited by 37 publications

References 6 publications

Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor

Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor

Characterization of photon counting pixel detectors based on semi-insulating GaAs sensor material

Chromium-compensated GaAs detector material and sensors

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