ePIC pfRICH mailing list

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

   Good morning colleagues,

  I believe a good fraction of our material budget problems close to the beam pipe can be fixed if one simply uses something like delrin instead of aluminum for the honeycomb sandwich reinforcement. See the comparison scans attached, where even without any further optimizations we are getting close to the ~15% rad length ballpark  numbers. Ignore the hot spot, it can obviously be optimized out.

  I don't see why would not it work for such small shapes, unless there are radiation hardness issues. Prakhar, Alex: I was wondering, can we commit to this option?

  One may ask a question why there is now no hot spot at theta angles, where a particle would cross either the inner vessel wall or the inner mirror wall in a "projective" way. The answer is illustrated in the attached sketch. Somewhat by accident, we tilted the inner mirror in such a way that such situations do not happen. Besides this, as also follows from the sketch, the wall and the mirror will never be crossed at the same time by any straight line originating from the IP. Therefore, for instance, it probably does not make much sense to try unifying the wall and the mirror into one layer.

  Regards,

    Alexander.

 

Attachment: aluminum.png
Description: aluminum.png

Attachment: delrin.png
Description: delrin.png

Attachment: vessel-sketch.pdf
Description: vessel-sketch.pdf