Abstract Details
| Name: Tanmoy Chattopadhyay Affiliation: Physical Research Laboratory, Ahmedabad Conference ID: ASI2015_703 Title : Development of a Hard X-ray Focal Plane Compton Polarimeter Authors and Co-Authors : 1. Santosh Vadawale, PRL 2. S. Goyal, PRL Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : Polarisation measurements of celestial astrophysical sources in X-rays offer unique opportunity of detailed study of behavior of matter in extreme gravitational and magnetic field. Hard X-ray polarimetry is specifically useful since at higher energies expected polarisation from the sources is higher than that at lower energies. Compton polarimeters when coupled with hard X-ray optics can provide sensitive polarisation measurements in hard X-rays with a broad energy band. In this regard, we are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI scintillators. The scatterer is of 5 mm diameter and 100 mm length obtained from Saint–Gobain as an integrated module containing plastic scintillator (BC404) coupled to a photo-multiplier tube (PMT; Hamamatsu R6095). In the polarimetric configuration, the scattered photons from plastic are collected by 16 CsI(Tl) scintillators (5 mm X 5 mm X 150 mm) which are read by Si Photomultiplier at the end of each of the CsI tubes. Sensitivity of Compton polarimeters critically depends on the lower energy detection limit of the active scatterer and the surrounding scintillators and thus it is important to know the characteristics of scintillators at lower energy depositions in order to have a realistic estimate of the energy range and sensitivity of Compton polarimeter. Here we describe briefly the characteristics of the plastic scatterer and the CsI absorbers. Finally we will show the preliminary experimental results obtained from the final configuration of the Compton polarimeter and compare with the simulation results. |