The Gamma-Ray Polarimeter Experiment (GRAPE) is a high-altitude balloon experiment designed for polarization studies of transient sources with a long-term goal of observing Gamma-Ray Bursts (GRBs) aboard a series of Long Duration Balloon flights (LDBs). Polarization studies of GRB prompt emission is necessary to constrain existing physics models describing the radiation processes and magnetic field structures of astrophysical jets. GRAPE is a wide field of view (FoV) Compton polarimeter measuring γ-ray polarization in the 50-500 keV energy range with a broad range (20 keV – 3 MeV) for spectroscopy. The novel 3-dimensional geometry of the current design provides GRAPE with Compton imaging in addition to polarization capabilities. The instrument consists of 245 optically isolated SiPM coupled to either high-Z (GAGG:Ce) or low-Z (para-Terphenyl) scintillator arranged in a 7x7x5 cuboid structure. At the center of the scintillator array two low-Z detectors contain a ~25 nCi Co-60 calibration source for onboard calibrations. A test flight of this design was flown on August 27, 2023, from Fort Sumner, NM to validate the scientific capability of the instrument design. We will report on res
Microchannel plate (MCP) detectors have been the workhorse detector for many applications, including space borne ultra-violet imaging and spectrographic instruments. Recent advances in additive manufacturing (AM) have enabled fabrication of complex structures with nano-scale resolution facilitating the production of highly customizable MCPs. Using AM to produce MCPs potentially has many advantages over traditional fused glass substrates, including better material control (e.g., more robust glasses or ceramics), better control of microscopic features (e.g., unique pore geometries to improve performance), and better control of macroscopic features (e.g., printing precision curved surfaces for focal plane matching). Through a collaboration with industry, national laboratory, and university partners, small format microcapillary array substrates were produced using a standard polymer photoresin. These substrates were functionalized using atomic layer deposition and their performance was compared to current state-of-the-art Pb-glass and borosilicate-glass MCPs.
The Gamma-Ray Polarimeter (GRAPE) is a wide field of view (FoV) Compton polarimeter measuring γ-ray polarization from transient sources such as Gamma-Ray Bursts (GRBs) in the 50-500 keV energy range with a broad range (20 keV – 3 MeV) for spectroscopy. The instrument is a 7x7x5 array of 245 optically isolated SiPMs each coupled to either a high-Z (GAGG:Ce) or low-Z (para-Terphenyl) scintillator. The novel design provides enables Compton imaging in addition to polarization capabilities, and Co-60 calibration sources (~25 nCi) imbedded within two centrally located low-Z detectors allow for onboard calibrations. We will report on the instrument performance of this design during a test flight on August 27, 2023, from Fort Sumner, NM.
Understanding the underlying physics governing astrophysical jets associated with Gamma-Ray Bursts (GRBs) is necessary to advance the field of gamma-ray astronomy. Existing physics models can be constrained through GRB polarization studies. The Gamma-Ray Polarimeter Experiment (GRAPE) is a high-altitude balloon experiment designed to measure GRB polarization over the energy range of 50-500 keV at flight altitudes. A flight of the newest GRAPE design is scheduled to fly from Fort Sumner, NM in August 2023. The new design is based on an arrangement of small scintillation detector elements designed to measure photon interactions in three dimensions and provide modest imaging capabilities. The flight instrument consists of a 3-dimensional (7x7x5) array of high-Z (GAGG) and low-Z (P-terphenyl) scintillators each read out by individual Hamamtsu MultiPixel Photon Counters (MPPCs). Previous GRAPE missions have been sensitive to M-class solar flares and observations of the Crab Nebula with low signal to background ratios. The new design improves performance relative to the previous GRAPE design through the use of advanced scintillator materials, the ability to perform modest Compton imaging for source localization and background rejection, and by completely eliminating optical cross-talk. Background reduction is achieved using the imaging capabilities allowing for some level of event rejection for events inconsistent with the source direction. This paper will present the new module design and simulated response parameters to provide an estimate of the balloon payload sensitivity.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.