ePIC pfRICH mailing list

["Kiselev, Alexander" <ayk AT bnl.gov>]

  Hello colleagues,

  as a follow up to our discussion during the pfRICH engineering meeting on Monday: I don't think we should fight for every hundred microns in minimizing the unavoidable small gap between the neighboring conical mirror sectors. As a matter of fact, the length as measured along a circumference of a single 30-degree sector is ~300mm. Therefore, even if a gap was ~1mm, we are talking about ~0.3% of a geometric efficiency loss, which is pretty much in the noise level. Obviously, in our presently anticipated mirror mounting scheme the gaps can be much smaller than that, so no problem whatsoever. I'd even argue that making these gaps reasonably large eliminates a possible reflection point ambiguity around a sector boundary in IRT, and may be a substantial relief in a relative sector alignment accuracy during installation.

  Regards,

    Alexander.