Mainz 2014 – scientific programme
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ST: Fachverband Strahlen- und Medizinphysik
ST 3: Biomedical Imaging II
ST 3.8: Talk
Tuesday, March 25, 2014, 18:30–18:45, RW 2
Characterization of the Dosepix detector under clinical conditions — •Francesca Bisello1,2, Felix Tennert2, Ina Ritter2, Andrea Zang2, Michel Campbell3, Winnie Wong3, Juan Carlos Celi2, Norbert Michel4, Gisela Anton2, and Thilo Michel2 — 1IBA Dosimetry, Schwarzenbruck — 2Eralangen Centre for Astroparticle Physics, Radiation and Detector Physics — 3Medipix Team, Microelectronics Group, CERN — 4Customized Microelectronic Solutions
The Dosepix detector is a spectroscopic hybrid single photon counting detector. The detector matrix is composed by 256 square pixels of two different sizes of sensitive area: 64 small pixels of 55 x 55 µm2 and 192 big pixels of 220 x 220 µm2. Energy information of the impinging radiation is provided by 16 energy bins for each pixel [1].
In this contribution, the detector is characterized for a use under clinical conditions, especially in mammography. A mammographic examination involves X-ray tube voltages from 20 to 35 kV and a photon flux of about 106 photons/mm2/s at 65 cm source detector distance.
Under these conditions, pile-up in the analog part of the pixel electronics caused by photons impinging closely spaced in time, is the major drawback of the photon counting technique. Pile-up affects, for example, the linearity between primary flux and detection rates and influences the measured energy spectra.In this contribution, we discuss the influence of pile-up on the measured photon rates and the energy resolution.
References
[1] W.S.Wong et al.,2012. doi:10.1088/1748-0221/7/01/C01056