The anti-coincidence detector for the GLAST large area telescope

Моисеев, А. А.; Hartman, R. C.; Ormes, J. F.; Thompson, D. J.; Amato, M.; Johnson, Thomas E.; Segal, K.; Sheppard, Dave

doi:10.1016/j.astropartphys.2006.12.003

Cited by 59 publications

(51 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All scintillator tiles are coupled to silicon photomultipliers (SiPM) by optical fibers. The architecture of the Upper-AC detector is fully derived from the successful design of the AGILE [108] and Fermi/LAT [95] AC systems. In particular, their segmentation has proven successful at limiting the "backsplash" self-veto, therefore the dead time of the instrument.…”

Section: Anticoincidence Systemmentioning

confidence: 99%

The e-ASTROGAM mission

et al. 2017

View full text Add to dashboard Cite

e-ASTROGAM ('enhanced ASTROGAM') is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV -the lower energy limit can be pushed to energies as low as 150 keV, albeit with rapidly degrading angular resolution, for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and the promise of eLISA.

show abstract

Section: Anticoincidence Systemmentioning

confidence: 99%

The e-ASTROGAM mission

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Note that the AntiCoincidence Detector, ACD, of EGRET was monolithic, which caused problems above 10 GeV: electromagnetic showers in the calorimeter produced backsplash that made a signal in the ACD, thus tagging high-energy gamma rays incorrectly as charged particles. To avoid this effect, the ACD for Fermi-LAT is divided into many scintillating tiles (see Moiseev et al 2007) and, therefore, Fermi-LAT provides us with a unique opportunity to study incoming gamma rays with energies above 10 GeV. At energies below ≈10 GeV, the accuracy of the directional reconstruction of photon events detected by Fermi-LAT is limited by multiple scattering, whereas above ≈10 GeV, multiple scattering is unimportant and the accuracy is limited by the ratio of the silicon-strip pitch to silicon-layer spacing (see Atwood 2007).…”

Section: Introductionmentioning

confidence: 99%

Counting gamma rays in the directions of galaxy clusters

Prokhorov

Churazov

2014

A&A

View full text Add to dashboard Cite

Emission from active galactic nuclei (AGNs) and from neutral pion decay are the two most natural mechanisms that could establish a galaxy cluster as a source of gamma rays in the GeV regime. We revisit this problem by using 52.5 months of Fermi-LAT data above 10 GeV and stacking 55 clusters from the HIFLUCGS sample of the X-ray brightest clusters. The choice of >10 GeV photons is optimal from the point of view of angular resolution, while the sample selection optimizes the chances of detecting signatures of neutral pion decay, arising from hadronic interactions of relativistic protons with an intracluster medium, which scale with the X-ray flux. In the stacked data we detected a signal for the central 0.25 deg circle at the level of 4.3σ. Evidence for a spatial extent of the signal is marginal. A subsample of cool-core clusters has a higher count rate of 1.9 ± 0.3 per cluster compared to the subsample of non-cool core clusters at 1.3 ± 0.2. Several independent arguments suggest that the contribution of AGNs to the observed signal is substantial, if not dominant. No strong support for the large contribution of pion decay was found. In terms of a limit on the relativistic proton energy density, we derived an upper limit of 2% relative to the gas thermal energy density, provided that the spectrum of relativistic protons is hard (s = 4.1 in dN ∝ p −s d 3 p). This estimate assumes that relativistic and thermal components are mixed. For softer spectra the upper limits are weaker and equal to 3% for s = 4.2, 4% for s = 4.3, and 6% for s = 4.4.

show abstract

“…EGRET was hampered in performing detailed studies of the -ray sky above 10 GeV, due to backsplash of secondary particles produced by high-energy -rays causing a self-veto in the monolithic anticoincidence detector used to reject charged particles and due to a noncalibrated detector response. GLAST, soon to be launched, will not be strongly affected by these problems, since the anticoincidence shield was designed in a segmented fashion (Moiseev et al 2007). The effective area of GLAST will be roughly an order of magnitude larger than that of EGRET, leading to an increased sensitivity for detecting celestial -ray photons (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Diffusion of Cosmic Rays and theGamma‐Ray Large Area Telescope: Phenomenology at the 1–100 GeV Regime

Marrero

Torres

Pozo

et al. 2008

Astrophysical Journal

View full text Add to dashboard Cite

This paper analyzes astrophysical scenarios that may be detected at the upper end of the energy range of the GammaRay Large Area Space Telescope (GLAST ), as a result of cosmic-ray (CR) diffusion in the interstellar medium (ISM). Hadronic processes are considered the source of -ray photons from localized molecular enhancements nearby accelerators. Two particular cases are presented: (1) the possibility of detecting spectral energy distributions (SEDs) with maxima above 1 GeV, which may be constrained by detection or nondetection at very high energies (VHEs) with observations by ground-based Cerenkov telescopes, and (2) the possibility of detecting V-shaped, inverted spectra, due to confusion of a nearby (to the line of sight) arrangement of accelerator/ target scenarios with different characteristic properties. We show that finding these signatures (in particular, a peak at the 1Y100 GeV energy region) indicates the underlying mechanism producing the -rays that is realized by nature, which accelerator (age and relative position to the target cloud) and under which diffusion properties CRs propagate.

show abstract

The anti-coincidence detector for the GLAST large area telescope

Cited by 59 publications

References 14 publications

The e-ASTROGAM mission

The e-ASTROGAM mission

Counting gamma rays in the directions of galaxy clusters

Diffusion of Cosmic Rays and theGamma‐Ray Large Area Telescope: Phenomenology at the 1–100 GeV Regime

Contact Info

Product

Resources

About