The project of a high-resolution and sensitivity (HRS) instrument for solar flare gamma-ray spectroscopy

Abstract

Fine-structure measurements of solar gamma-emission lines are possible in the framework of high-resolution and sensitivity (HRS) spectroscopy only. Here we present the project of HRS instrument which includes Germanium and scintillator spectrometers. The Ge-spectrometer will cover the range 0.015–10 MeV with a resolution of ∼0.2% at 1 MeV. It consists of an array of Ge-detectors cooled to <90K. The scintillator spectrometer will cover the energy range 0.1–50 MeV with a resolution ∼10% at 0.66 MeV. It consists of 6 identical NaI(Tl)CsI(Tl) modules (operate in phosphich mode) with crossed axes (effective area ∼ 1000 cm 2, FOV ∼ π sr). Such detector configuration allows to select quanta falling inside and outside instrument FOV, that leads to decrease of the background level and guarantees high sensitivity. Both detector systems together allow to make accurate measurements of all parameters of the expected gamma-lines and to detect gamma-lines in wide energy range in power and weak solar flares.