3D reconstruction of particle tracks in a 2 mm thick CdTe hybrid pixel detector

AbstraktAbstract

We demonstrate how the latest generation of hybrid pixel detectors of the Timepix family can be used to reconstruct 3 dimensional particle tracks on a microscopic scale, additionally determining the stopping power along the particles' paths. In an experiment, a Timepix3 detector with a 2mm thick planar CdTe sensor was irradiated in a 40GeV/c pion beam and used in a similar way to a time-projection chamber: The coordinates x and y were given by the trajectory projection (pixel pitch: 55µm), the z-coordinate was reconstructed from the charge carrier drift time measurement (time binning: 1.5625ns). The achievable z-resolution was studied at different bias voltages. Systematic inaccuracies due to an imprecise drift time model were determined and separated from the intrinsic uncertainty given by the time resolution. It was shown that a z-resolution of m could be achieved by a perfect modeling of the drift time. With the presented z-reconstruction methodology, we studied the charge collection efficiency as a function of interaction depth, which was then used to apply a charge loss correction to the per-pixel energy measurements. 3D event displays of pion, muon and electron tracks are shown.

We demonstrate how the latest generation of hybrid pixel detectors of the Timepix family can be used to reconstruct 3 dimensional particle tracks on a microscopic scale, additionally determining the stopping power along the particles' paths. In an experiment, a Timepix3 detector with a 2mm thick planar CdTe sensor was irradiated in a 40GeV/c pion beam and used in a similar way to a time-projection chamber: The coordinates x and y were given by the trajectory projection (pixel pitch: 55µm), the z-coordinate was reconstructed from the charge carrier drift time measurement (time binning: 1.5625ns). The achievable z-resolution was studied at different bias voltages. Systematic inaccuracies due to an imprecise drift time model were determined and separated from the intrinsic uncertainty given by the time resolution. It was shown that a z-resolution of m could be achieved by a perfect modeling of the drift time. With the presented z-reconstruction methodology, we studied the charge collection efficiency as a function of interaction depth, which was then used to apply a charge loss correction to the per-pixel energy measurements. 3D event displays of pion, muon and electron tracks are shown.