Optimization of the design of a cosmic hard X-ray polarimeter by Monte Carlo calculation

The development of a Compton-scatter X-ray polarimeter is taking place to observe the linear polarization of cosmic hard X-ray sources. The polarimeter consists of a scatterer of plastic-scintillator and four NaI scintillation counter to catch scattering X-rays. The size of the scatterer in the 50-100 keV energy range was optimized with the aid of a Monte Carlo simulation assuming the observation of Cyg X-1 at a balloon altitude. The plastic-scintillator of 5 inch in diameter and 6 cm in thickness was better as the scatterer in the calculation. The minimum detectable polarization at 3 standard deviation for Cyg X-1 in a 60 min. observation time is 10% in the designed detector. (author)