Speaker
Description
We present an evaluation of the timewalk effect in the new Timepix4.2 pixel detector ASIC, bump-bonded to a $300~\mu$m planar silicon sensor. We show a comparison between three different methods – using test-pulse data, photon data, and charged-particle data, and discuss the scope of the application of each.
Charged-particle data was obtained at the PSI PiM1 beam line using coincidence with a MALTA-based beam telescope. The positron beam was used to study the fractional radiation length of test detector modules. The time of flight of scattered particles was measured by the Timepix4 with respect to a beam clock, thus separating in time the positron component of the beam from muon and pion contamination. After applying a timewalk correction based on test-pulses and the charged beam data, the FWHM of the positron peak decreases from $\sim4~$ns to $\sim2~$ns, limited by the trigger system of the telescope.
Additional photon data was taken with an IR laser. The timewalk extracted from this is compared to the above and the characteristics of the output signal are discussed.
