sPHENIX tracking discussion

["Frawley, Anthony" <afrawley AT fsu.edu>]

Hi All,

Here are my notes from yesterday's tracking meeting.

Please see also the email from Ed O'Brien sent to this list earlier today.

Best regards

Tony

Tom Hemmick - Comments on the PHENIX DC for sPHENIX
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Tom showed some estimates of occupancy for the drift chamber outer tracker proposed by Yasuyuki at the June 24 general meeting. The conclusion was that the drift chamber would have ~ 100% occupancy in sPHENIX for Au+Au collisions, making it unusable.

Slide 2: Itaru said that the cell size in Yasuyuki's slides is a typo, YA meant the cell size to be the same as in PHENIX. Fixing this  drops Tom's occupancy estimates from 200% to 100%.

Slide 3: The fact that 1/2 of the hits are not from primary tracks is attributed to "spiralers" that curl up in the field. This suggests we should expect a similar increase of x2 in hits in sPHENIX, based on the STAR experience.

Ed noted that he had done similar estimates to Tom, and reached similar conclusions. Ed will send around memo with details (see email to sphenix-tracking-l this morning by Ed).

We skipped the posted slides on the DC option, since Yasuyuki was traveling and could not call in.

Itaru Nakagawa - Si strip tracker status report
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Itaru gave a status report on the silicon strip development, refocused on using them in an intermediate tracker.

The proposed strips are 12 mm long in the z direction. There was some discussion about whether this would allow them to resolve confusion caused by event pileup, since the TPC electrons drift on 6 mm between beam crossings. It was suggested to look at how far the z length of the silicon cells can be reduced at the expense of the pitch. Itaru said that Mike McCumber had suggested possibly changing the direction of the strips to vertical for some layers