Simulation Study of Accuracy of Calculated Single Photon Event Position with Sub-pixel Spatial Resolution in Charge Couple Device

Abstract It has been a long-term effort to get higher energy resolution for experiment detector. Usually the can be converted from spatial though mechanical setup. To shrink pixel size of detector takes lot efforts, time and is limited by integrated circuit technology. So centroid algorithm widely used increase resolution. Through electron cloud diffusion, excited electrons are distributed among nearby pixels. Using algorithm, photon impact point calculated. However, accuracy calculated position affected relative within signal noise ratio (SNR). There systematic bias offset, or edge effect, toward center when near perimeter pixel. Also SNR an important factor which affects position. In this study, we try calculate simulated event positions three algorithms, 3x3 centroid, 5x5 two-dimensional Gaussian profile fit. A simulation 2000 x 1000 pixels’ image with specific filled first then sparsely randomly 200 shaped events avoid pile up. Since original points well known, compared data verify their accuracy. The noise, SNR, also adjusted different images see its effects on shows as seen in previous using centroid. For will not disappear even high. better than high but degrades faster decreases. 2D-Gaussian fit provide estimation at same minimized. iteration process diverge no optimized answer attained too low. position, defined inverse error standard deviation, proportional 2-D