Presentation details
» The capabilities of the Timepix detector for X-ray polarimetry
Presentation duration: 20 minutes
Presenter: Thilo Michel
The hybrid semiconductor photon counting pixel detector Timepix has been used for measurements of linear X-ray polarization exploiting photoelectric and also Compton effect in the 300 micrometre thick silicon sensor layer. For polarized X-rays with energies between 27 and 84 keV we were able to measure an asymmetry between vertical and horizontal double hit events in neighbouring pixels of the detector at room temperature. The Timepix was used in the time-over-threshold-mode to measure the dependence of the polarization asymmetry on energy deposition in the sensor. Asymmetries between 0.2 % at 29 keV and 3.4 % at 78 keV were achieved in agreement with simulation results. Additionally, we used the time-to-shutter mode of the Timepix to identify Compton scattering events in the sensor by coincidence techniques. A modulation factor of about 65 % could be achieved. In this contribution we will describe the measurement principles of X-ray polarization using the photoelectric and Compton effect with hybrid pixel detectors, show measurement and simulation results of analyzing power and modulation factor and discuss potential for improvements.
Coauthors:- Jürgen Durst
- Florian Bayer
- Jan Jakubek