Cylinder segment surface

[armin-ilg]

BEGINRELEASENOTES

• DDRec::VolSurface: Adding the capability to be only a segment of a cylinder <2π needed for ultra-light curved vertex concept.
  ENDRELEASENOTES

Hi everyone

I'm trying to make the ultra-light vertex detector concept working in full simulation, using k4geo from this PR. As a first step I added the functionality to VolCylinder to feature less than 2π circumference, changing the getLines function. Is there something else needed? Have in the past cylindrical sensitive surfaces actually been used in reconstruction?

Thank you,
Armin

Sensitive surfaces example:

[andresailer]

I converted this to a draft, until the whole chain is confirmed to be fully working.

[gaede]

Hi Armin,
I believe that adopting the getLines() as you have done should be all that is needed for Cylinders <2pi as the 'boundary' of the surface is handled by the volume. We use cylindrical surfaces for tracking in the ILD TPC, see e.g.:
https://github.com/iLCSoft/DDKalTest/blob/master/src/DDCylinderMeasLayer.cc
https://github.com/key4hep/k4geo/blob/main/detector/tracker/TPC10_geo.cpp
Cheers, Frank.