WG-D meeting, August 1, 2007
Present: Parker, Seryi, Corvin, Maruyama, Keller, Sanami, Jeremie, Burrows, Kozanecki, Tauchi, Yamamoto, Markiewicz (+ possibly other colleagues).
First, discussed the charge to the group and what needs to be added. And then discussed the interface document.
Suggested to add global approach to background explicitly. Next meeting -- discuss status and plans.
Comments: In Belle beam-gas determined IR design, and that worked well; but it took 3 years of operation to get synchrotron radiation under control. In Babar beam-gas & SR together drove the design. In SLC the SR produced by beam tails in the final quads was the big issue in practice.
For SR and collimation, need to consider a reasonable non-ideal case and design to that.
Suggested to include study of vacuum IR chamber shape and masking w.r.to active detectors (optimization depends on the weight of high E versus Z physics). Simulations of benchmark processes could be used to study this.
Suggested to include review of expected achievable collimation depth, wakes, etc.
Study how much RF power penetrate and deposited at cold bore.
Beam gas -- being finished, still need to include inelastic hadron interaction in IR (which could determine the pressure requirement for QD0-QD0 drift) and then can review at the WG-D meeting.
Vacuum -- what is expected? How soon a mono-layer will form on a cold bore? Will discuss with vacuum experts.
Long term stability need to be added into interface document. In particular, when detectors (of different weight) move in and out, what is requirement on reproducibility of position? What rate of settlement is acceptable?
Alignment of FD -- do we need any HLS or interferometers and corresponding penetrations through the pacman? Would capacitive or LVDT sensors be sufficient?
Segmentation of detector and muon hermeticity. Discussion of eight "75 mm" plates which are used in GLD to reinforce the split-into-four-pieces door. These plates reduce hermeticity. This need to be studied -- find people.
Magnetic field -- requirements need to be worked out. Effect of pacman iron on the field along the beamline should be included. Contact LEP-II colleagues to find what effect they had due to magnetic field.
Add specification to the interface document that we are considering range of L* of 3.5-4.5m.
Make study to understand in more details what are implication for tuning time, etc.
Sanami-san presented radiation physics calculations (see attached).
Actions for the next meeting (Wed next week, Aug. 8, same time):
-- Report about status of background studies and plans.
-- Start creating vacuum model.
-- Find people to do mu-hermeticity study.
-- Review vacuum requirements including hadron inelastic scattering.
-- Develop magnetic field requirements, get LEP-II feedback.
-- Assign people to do different L* study.
-- Specify long term stability, repeatability and settlement rate.
-- Find people who can study benchmark processes for different vacuum chamber shape and different masking.
-- Discuss about pacman penetrations with alignment experts.
-- Report about present status of collimation capabilities, wakes, SR and suggest plan of studies.
