The meeting opened at 15:00 and closed at 15:55.
The number of attendees was stable at 24.

General news:

• The 4th DRD3 week took place at CERN, 10th to 14th of November: https://indico.cern.ch/event/1581713/
  • Good progress towards WG4 research goals from different groups
• The 7th Allpix Squared workshop will take place in Vienna, 28th to 30th of April 2026.

Sebastian Onder presented work Towards a Validated Mobility Model for 4H-SiC Detectors

• 4H-SiC parameters are inconsistent across literature
• Measurements for mobility parameters carried out
• Parameters used in an end-to-end simulation workflow, combining TCAD, Allpix Squared, and QUCS (for front-end electronics simulations)
• Important to include the inductance of the wirebond in the circuit simulations to reproduce the experimental results fully

Questions and Answers:

• Håkan W: For the simulations of alpha particle incidence, do you include air in the setup, as this may account a bit for the discrepancy? SO: No, it's in vacuum, but the measurements were also carried out in vacuum.
• Michael Moll: Why do you use Allpix Squared? Why not just TCAD, to get the transient pulses as well? SO: It is faster, and more flexible. In the end the pulses from simulations match data better when using Allpix Squared, compared to using TCAD. MM: Why is it different? SO: We do not fully know yet.
  • Anastasiia Velyka: The charge deposition you use in TCAD is probably different than what you use in Allpix Squared. The rest should be almost identical.
  • Kevin Heijhoff: TCAD gives  a bit more smeared-out signal also in silicon. The diffusion might be different; there is potentially too much diffusion in TCAD.
• Anastasiia Velyka: Why do you think that the electric field is not uniform? SO: The doping concentration in the sensor is not fully uniform.
• Vagelis Gkougkousis: The Cauchy-Thomas mobility model is a low-field experimental fit. It is not valid at high fields, but a different and more sophisticated approach is needed.
  • Kevin H: I don't think sdevice handles this.
  • Anastasiia V: I think it can do.
• Marco M: You mentioned you need a fine mesh in TCAD. How do you balance it when going to a regularised mesh in Allpix Squared? SO: I use a finer mesh than the finest part in TCAD, and then it's fine, we don't lose any information.

The conveners will announce the time for the next meeting via email.

Please get in touch if you wish to give a longer presentation.

Happy holidays!