Speaker
Dr
Giulio Pellegrini
(Univ. Autonoma de Barcelona, Spain)
Description
Charge sharing is an important factor to be considered in pixel
detector design for single-photon counting electronics. Its effect
on such devices, if proper adjustment of the pixel threshold is not
performed, is to give rise to false counts in the pixels
neighbouring the hit one. Nevertheless, it is difficult to evaluate
or measure, as single-photon counting electronics do not give
information about the charge quantity collected in every single
pixel. In this work we present the results obtained measuring an X-
ray source with a CdTe detector bump-bonded to a Medipix2 chip.
Medipix2 is a single-photon counting read-out chip that also
features a small matrix of 3×3 pixels with an analog output. The
signal generated by an incoming particle can therefore also be read-
out through an oscilloscope, making possible a detailed study of
charge sharing. The detector features a pixel pitch of 55 µm and a
thickness of 1 mm. The measurements presented here were taken in the
framework of our medical imaging research; therefore energies of
interest are below 100 keV. This study has general impact on the
design of pixel detectors; however its impact on the design and the
operation of pixel detectors coupled to photon counting electronics
is deeper.
Primary author
Dr
Giulio Pellegrini
(Univ. Autonoma de Barcelona, Spain)
