Gamma-Ray Spectrometry in the Energy Range 0.5–5 MeV

MeV-range velocity-space tomography from gamma-ray and neutron emission spectrometry at JET

We demonstrate the measurement of a 2D MeV-range ion velocity distribution function by velocity-space tomography at JET. Deuterium ions were accelerated into the MeV-range by third harmonic ion cyclotron resonance heating. We made measurements with three neutron emission spectrometers and a highresolution γ-ray spectrometer detecting the γ-rays released in two reactions. The tomographic inversi...

Are There MeV Gamma-Ray Bursts?

It is often stated that gamma-ray bursts (GRBs) have typical energies of several hundred keV, where the typical energy may be characterized by the hardness H , the photon energy corresponding to the peak of νFν . Among the 54 BATSE bursts analyzed by Band et. al. more than half have 100keV < H < 400keV. Is the narrow range of H a real feature of GRBs or is it due to an observational bias? We co...

ON THE ORIGIN OF THE MeV GAMMA-RAY BACKGROUND

In this paper, we suggest a new hypothesis for explaining the spectrum of the extragalactic MeV γ-ray background as observed by COMPTEL and SMM. We propose that both the flux level and spectrum can be accounted for as a superposition of non-thermal MeV tails in the spectra of Seyfert galaxies and other AGN. Although present detectors are not sensitive enough to obtain MeV data from individual e...

Contribution to the Nsac Long-range Plan the Future of Gamma-ray Spectroscopy: Greta, the Gamma-ray Energy Tracking Array

Angular Correlations of the Mev Cosmic Gamma Ray Background

The measured cosmic gamma ray background (CGB) spectrum at MeV energies is in reasonable agreement with the predicted contribution from type Ia supernovae (SNIa). But the characteristic features in the SNIa gamma ray spectrum, weakened by integration over source redshifts, are hard to measure, and additionally the contributions from other sources in the MeV range are uncertain, so that the SNIa...