The X-ray polarimeter of solar flares for the Interhelioprobe mission: a study of the characteristics of the physical model using radioisotope radiation sources

Abstract

The paper describes the physical model of the PING-P polarimetry unit of the PING-M X-ray polarimeter. The polarimeter is developed jointly by the Ioffe Institute and the Institute of Astrophysics of the Moscow Engineering Physics Institute for the Interhelioprobe mission. The model (PING-P-FM), made by the Ioffe Institute, represents the detector part of the polarimeter. The polarization degree is determined by the measurement of the asymmetry of the scattered radiation field. The device uses active scatterers based on paraterphenyl crystals for detecting the events of Compton scattering. A useful signal is the coincidence of pulses from one of the active scatterers (detector-scatterer) and one detector-receiver of scattered radiation. The polarimetry unit contains 3 detector-scatterers and 6 detector-receivers, thus resulting in 18 measurement channels. The requirements for instrument symmetry and stability of the measuring channels are high. The paper presents the results of an experimental study of the parameters of the measuring channels of the PING-P-FM model and their calibrations at different X-ray energies using Cd-109, Am-241, and Ba-133 isotope sources.