Detector and imaging systems for the gamma-ray imager/polarimeter for solar flares (GRIPS) instrument

Duncan, Nicole; Shih, Albert Y.; Hurford, G. J.; Saint-Hilaire, Pascal; Zoglauer, Andreas; Bain, H. M.; Amman, M.; Boggs, Steven E.; Lin, R. P.

doi:10.1117/12.2024667

Cited by 3 publications

(4 citation statements)

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“…When the cryocooler was briefly turned off, we were able to achieve line widths comparable to that previously reported for the GRIPS signal readout chain in a test cryostat cooled via liquid nitrogen: 3.5 keV FWHM at 59.5 keV. 2 The ∼30 keV low-energy spectral cutoff was determined by a combination of triggering thresholds, set to minimize spurious triggers, and the atmospheric energy cutoff, determined by the payload altitude and solar elevation in the sky. Due to the size of the ionization clouds and associated effects, there are not significant single-strip energy depositions above ∼1 MeV.…”

Section: Spectrasupporting

confidence: 67%

“…A complete description of the signal readout chain, including the ASIC electronics, can be found in an earlier manuscript. 2 Preliminary line-width measurements show a typical energy resolution of 5 keV FWHM at 59.5 keV, but we are still refining our approach to subtracting common-mode noise. Due to the fine strip pitch and dense circuit traces, there is significant correlated noise between multiple channels that can be quantified and removed.…”

Section: Spectramentioning

confidence: 91%

“…A detailed description of these components, the GRIPS science instrument overall and its support systems can be found in earlier manuscripts. 1,2 Figure 3 shows a schematic of the complete payload and its systems. In this section we give a general review of key systems, highlight instrumental milestones and discuss changes since we last reported on GRIPS.…”

Section: Instrument Outline and Overviewmentioning

confidence: 99%

“…This paper reports on the details of GRIPS' first flight and provides updates on critical system changes and milestones since the previous GRIPS papers. 1,2 Figure 1: The fully integrated GRIPS instrument payload. The gondola is suspended from "The Boss" launch vehicle while the GRIPS and Columbia Scientific Ballooning Facility (CSBF) teams complete pre-flight checklists during a launch attempt.…”

Section: Introductionmentioning

confidence: 99%

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First flight of the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument

Duncan

Saint-Hilaire²,

Shih

et al. 2016

SPIE Proceedings

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The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument is a balloon-borne telescope designed to study solar-flare particle acceleration and transport. We describe GRIPS's first Antarctic long-duration flight in January 2016 and report preliminary calibration and science results.Electron and ion dynamics, particle abundances and the ambient plasma conditions in solar flares can be understood by examining hard X-ray (HXR) and gamma-ray emission (20 keV to 10 MeV). Enhanced imaging, spectroscopy and polarimetry of flare emissions in this energy range are needed to study particle acceleration and transport questions. The GRIPS instrument is specifically designed to answer questions including: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? GRIPS's key technological improvements over the current solar state of the art at HXR/gamma-ray energies, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), include 3D position-sensitive germanium detectors (3D-GeDs) and a single-grid modulation collimator, the multi-pitch rotating modulator (MPRM). The 3D-GeDs have spectral FWHM resolution of a few hundred keV and spatial resolution <1 mm 3 . For photons that Compton scatter, usually 150 keV, the energy deposition sites can be tracked, providing polarization measurements as well as enhanced background reduction through Compton imaging. Each of GRIPS's detectors has 298 electrode strips read out with ASIC/FPGA electronics. In GRIPS's energy range, indirect imaging methods provide higher resolution than focusing optics or Compton imaging techniques. The MPRM gridimaging system has a single-grid design which provides twice the throughput of a bi-grid imaging system like RHESSI. The grid is composed of 2.5 cm deep tungsten-copper slats, and quasi-continuous FWHM angular coverage from 12.5-162 arcsecs are achieved by varying the slit pitch between 1-13 mm. This angular resolution is capable of imaging the separate magnetic loop footpoint emissions in a variety of flare sizes. In comparison, RHESSI's 35-arcsec resolution at similar energies makes the footpoints resolvable in only the largest flares.

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Section: Spectrasupporting

confidence: 67%

Section: Spectramentioning

confidence: 91%

Section: Instrument Outline and Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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