High energy resolution hard X-ray and gamma-ray imagers using CdTe diode devices

Abstract

We developed CdTe double-sided strip detectors (DSDs or cross strip detectors) and evaluated their spectral and imaging performance for hard X-rays and gamma-rays. Though the double-sided strip configuration is suitable for imagers with a fine position resolution and a large detection area, CdTe diode DSDs with indium (In) anodes have yet to be realized due to the difficulty posed by the segmented In anodes. CdTe diode devices with aluminum (Al) anodes were recently established, followed by a CdTe device in which the Al anodes could be segmented into strips. We developed CdTe double-sided strip devices having Pt cathode strips and Al anode strips, and assembled prototype CdTe DSDs. These prototypes have a strip pitch of 400 micrometer. Signals from the strips are processed with analog ASICs (application specific integrated circuits). We have successfully performed gamma-ray imaging spectroscopy with a position resolution of 400 micrometer. Energy resolution of 1.8 keV (FWHM: full width at half maximum) was obtained at 59.54 keV. Moreover, the possibility of improved spectral performance by utilizing the energy information of both side strips was demonstrated. We designed and fabricated a new analog ASIC, VA32TA6, for the readout of semiconductor detectors, which is also suitable for DSDs. A new feature of the ASIC is its internal ADC function. We confirmed this function and good noise performance that reaches an equivalent noise charge of 110 e- under the condition of 3-4 pF input capacitance.

6 pages, 10 figures, accepted for publication in IEEE Transactions on Nuclear Science

References in corpus (5)

• Recent Progress in CdTe and CdZnTe Detectors
• Performance of a Low Noise Front-end ASIC for Si/CdTe Detectors in Compton Gamma-ray Telescope
• Investigation of charge sharing among electrode strips for a CdZnTe detector
• Low Noise Double-Sided Silicon Strip Detector for Multiple-Compton Gamma-ray Telescope
• Development of Uniform CdTe Pixel Detectors Based on Caltech ASIC

Cited by in corpus (12)

• The Medium Energy (ME) X-ray telescope onboard the Insight-HXMT astronomy satellite
• The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)
• FOXSI-2: Upgrades of the Focusing Optics X-ray Solar Imager for its Second Flight
• Constraining Hot Plasma in a Non-flaring Solar Active Region with FOXSI Hard X-ray Observations
• Probing entanglement in Compton interactions
• Fine-pitch semiconductor detector for the FOXSI mission
• A compact imaging system with a CdTe double-sided strip detector for non-destructive analysis using negative muonic X-rays
• Tomographic Imaging by a Si/CdTe Compton Camera for In-111 and I-131 Radionuclides
• 2-mm-Thick Large-Area CdTe Double-sided Strip Detectors for High-Resolution Spectroscopic Imaging of X-ray and Gamma-ray with Depth-Of-Interaction Sensing
• Fine-pitch CdTe detector for hard X-ray imaging and spectroscopy of the Sun with the FOXSI rocket experiment
• In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)
• Imaging and Spectral Performance of a 60 μm Pitch CdTe Double-Sided Strip Detector