Fine-pitch CdTe detector for hard X-ray imaging and spectroscopy of the Sun with the FOXSI rocket experiment

Abstract

We have developed a fine-pitch hard X-ray (HXR) detector using a cadmium telluride (CdTe) semiconductor for imaging and spectroscopy for the second launch of the Focusing Optics Solar X-ray Imager (FOXSI). FOXSI is a rocket experiment to perform high sensitivity HXR observations from 4-15 keV using the new technique of HXR focusing optics. The focal plane detector requires < 100 um position resolution (to take advantage of the angular resolution of the optics) and about 1 keV energy resolution (FWHM) for spectroscopy down to 4 keV, with moderate cooling (> -30 C). Double-sided silicon strip detectors were used for the first FOXSI flight in 2012 to meet these criteria. To improve the detectors' efficiency (66 at 15 keV for the silicon detectors) and position resolution of 75 um for the second launch, we fabricated double-sided CdTe strip detectors with a position resolution of 60 um and almost 100 % efficiency for the FOXSI energy range. The sensitive area is 7.67 mm x 7.67 mm, corresponding to the field of view of 791'' x 791''. An energy resolution of about 1 keV (FWHM) and low energy threshold of 4 keV were achieved in laboratory calibrations. The second launch of FOXSI was performed on December 11, 2014, and images from the Sun were successfully obtained with the CdTe detector. Therefore we successfully demonstrated the detector concept and the usefulness of this technique for future HXR observations of the Sun.

8 pages, 6 figures, accepted for publication in the Journal of Geophysical Research - Space Physics

References in corpus (5)

• High energy resolution hard X-ray and gamma-ray imagers using CdTe diode devices
• The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)
• The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR
• Constraining Hot Plasma in a Non-flaring Solar Active Region with FOXSI Hard X-ray Observations
• Fine-pitch semiconductor detector for the FOXSI mission

Cited by in corpus (4)

• FOXSI-2 Solar Microflares II: Hard X-ray Imaging Spectroscopy and Flare Energetics
• High-speed X-ray imaging spectroscopy system with Zynq SoC for solar observations
• Imaging and Spectral Performance of a 60 μm Pitch CdTe Double-Sided Strip Detector
• Imaging and Spectral Performance of a Wide-gap CdTe Double-Sided Strip Detector