Si3 PLAN FOR DETECTOR COMPLETION

(A DISCUSSION DOCUMENT)

PURDUE GROUP

• The earliest possible date for installation of Si3 into CLEO/CESR is early February 2000.
• When does Si3 need to be in Ithaca to be ready for a February installation?
• It takes about one month to assemble Si3 around the beam-pipe. A further month should be allowed for testing and debugging by the local team. (discuss)
• Down time over the Holiday Season should be realistically taken into account (2 weeks?)
• The above three points imply we should aim to have the detector in Ithaca by Thanksgiving, (allows a month for testing excluding Holidays) and certainly no later than early December (allows a month for testing if work through Holidays)
• Can we complete the detector on this time-scale?
• The following is our current best estimate of the schedule for completion of the detector.
• New layer 2 starters arrived safely yesterday, plan to build replacement for FL208 starting before the weekend. Once FL208 is mounted and tested we will reconstruct FL202. (This is the cautious approach). If all goes well the 2^nd clamshell will be complete by the end of October.
• Once 2^nd clamshell is complete it will be shipped to Cornell by Purdue plane. We have booked the first available date Nov. 11, with a request for an earlier date if one becomes available. (Other options including non-Purdue planes etc. could also be explored, comments please)
• Layer 3 currently has two known problem parts FL311 and HL324 (in-recovery). There are two ladders to build and 8 ladders to mount.
• If all goes well Layer 3 can be complete as early as the end of October.
• Since L4's can be installed at Cornell, should the detector be shipped as soon as L3 is complete? Our view is no, we believe it is important to gain experience in L4 mounting and learn if there any problems. Purdue is the best place for that: 3 people with mounting experience, back-up coverage, rapid fixture modification capabilities etc.
• However if there are L4 problem parts (stragglers), the optimum scenario for completing the detector is unlikely to be that all L4's are mounted at Purdue
• We propose as soon as layer 3 mounting is complete layer 4 mounting will commence.
• If it becomes clear that layer 3 will not be ready by end of October we propose to commence mounting layer 4, without waiting to finish layer 3 (this idea should be discussed again in about a week).
• We are not yet sure how quickly we will be able to proceed with layer 4 mounting, somewhere between 1 and 2 ladders per day is likely.
• We propose Layer 4 mounting to commence on November 1, and barring unforeseen problems, mounting at 1 L4 ladder/day è ship December 8, at 2 L4 ladders/day è ship Thanksgiving week. A date in between these two limits is likely (December 2)
• Since L4's can be installed at Cornell, once the supply of layer 4 ladders awaiting mounting at Purdue is exhausted, we propose the L3/4 assembly will be shipped to Cornell by plane. We will not wait for L4 stragglers, IN THIS WAY WE CAN LOCK-IN A DATE NOW!
• The Purdue plane is available on November 24 and December 2, we have booked the latter date.
• Comments on labor: the above time estimates are for current staffing levels 4 FTE (mech: Jim and Tom)

• We would still welcome additional help (see several Sept e-mail requests), but there is little time for training.