Comparing different methods of position reconstruction considering 1D readout of GEM detectors

Abstract

Gas Electron Multiplier (GEM) based detectors contain microstructures that provide amplification, via avalanche multiplication, for the charges generated due to ionizing radiation. The readout of the detector is responsible for collecting electrons multiplied by the GEM structure and it may be position sensitive. In this preliminary study, we created algorithms to compare the error of three different methods for position reconstruction. All these methods are based on weighted averages. In the algorithm we modeled an electron cloud as a normalized Gaussian function that is collected by a 1D readout of strips affected by white noise, then we made a clustering algorithm to identify the strips that collected the electron cloud. The method that uses the weight equal to squared charges shows the highest errors for narrow clouds, when the σ value (standard deviation of a Gaussian function) is closer to the strip width. Nonetheless, the errors of the three methods get similar results for a σ approximately equal to the width of one and a half strips.