Imaging Observation of MeV-Gamma-Rays from relativistic electron precipitation using an Electron Tracking Compton Camera with Balloon Borne Experiment around the Northern Polar Cap
Prof. Toru Tanimori
Department of Physics, Faculty of Science
Kyoto University
Kyoto
Japan
Abstract
We develop the SMILE-II balloon-borne low-energy gamma ray detector, an Electron Tracking Compton Camera (ETCC), for long-duration experiment to catch gamma-rays from both celestial targets and high energy particle precipitation on the polar region. By measuring the 3D-track of a recoil electron, ETCC can measure the direction of incident gamma-rays photon by photon with a 3 steradian wide field of view (FoV), and provides both a good background rejection and an angular resolution of 1 degree at 1MeV. The energy range and wide FoV of the SMILE-II are suitable for observing Bremsstrahlung from relativistic electrons precipitating into atmosphere and also fast neutrons from proton precipitation. By measuring the energy and the depth of gamma rays in the atmosphere from observed gamma-ray image, the position of the precipitation is determined. Also weak precipitation events less than atmospheric gamma ray background can be measured, which will provide us its full dynamic range and the quantitative estimate of the flux of the precipitating electrons. Based on MAXIS experiment results, several REP events per one day would be detected by SMILE-II. We propose a ground-based measurement campaign, including the EISCAT radars, all-sky cameras and photometers, as well as suitably located VLF receivers in support of the SMILE-II balloon campaign. The balloon experiment would be launched from Esrange in 2013 corresponding to the solar maximum activity.
Created 2012-01-09 11:05:18 by Mats Holmström Last changed 2012-01-20 11:02:37 by Uwe Raffalski
