Minutes of FPS detector meeting, 9/14/99 at BNL, Rm. 2-160, 9-10:30 am In attendance: S. Desai (scribe), M. Rijssenbeek, A. Talalaevskii, J. Steffens, J. Brody, A. Patwa (co-scribe), P. Yamin ------------------------------------------------------------------------ Main Agenda: Status report on FPS LED calibration system (A. Talalaevskii, M. Rijssenbeek) Discussion (all) ------------------------------------------------------------------------ o M. Rijssenbeek gave a status report on the production of calibration systems and individual parts required for the system (i.e. connectors, resistiors, boards, fibers, etc...) The bottleneck at this stage is getting fibers. Further, for reference, the following table describes the total soldering and assembly we have at the moment (adapted from MR's table, as of Sept. 14, 1999): Item Assembled 1. solder Resistors 40 2. solder LEDs 30 3. solder connector 45 4. assembled support 90 5. Total Assembly 15 6. fiber stop (glue beads) 34 7. fiber insertion 0 8. packaging 0 Fiber insertion hasn't begun since 24" fibers are not fully delivered from fermilab but we've suggested to begin assembling with the 34 long (24") and 840 short (21") fibers that we currently have on hand in SB. The remaining, final batch of long fibers can then be inserted upon arrival from fermilab and "continue" production from there. o A. Talalaevskii showed us the reference system box which he has constructed. It still needs a little more work but is largely completed. o A. Talalaevskii also presented preliminary measurements of the 1 MIP signal. However, they did not exhibit the appropriate behavior as the discriminator threshold used to generate the gate was varied. S. Desai spoke with A. Talalaevskii last night (Sept. 14), at which time he appeared to have overcome the problem by amplifying the PMT output *before* splitting the signal into data and trigger signals. o J. Steffens has completed another 8x8 Matrix for the MAPMT. While A. Talalaevskii is completing the MIP meausrements and finishing up the reference box, S. Desai will be using this to choose channels for use during installation and tuning of the calibration systems. o J. Steffens & co. are presently working on a fixture/jig to put beads/stoppers on clear fiber ends that get inserted to cylinders. this will be some fixture with 9-channels that provides better glue uniformity around individual clear fibers and allows more to be assembled with stoppers than previously. o The system configuration for calibration system tuning will be [Module+Cal Sys]c1[Clear Fibers]c2[Dark Box w/ MAPMT], w/ c1 and c2 as connectors. Once we have the Clear Fibers and Dark Box, channel to channel gain calibration (downstream of c1) will be done using Andrei's reference system,as it will be tuned to produce uniform output. o We still need to settle the issue of the design and construction of The Dark Box (we could conceivably use the one already in the clean room, in which case we need to decide how it should be modified). That is, the large box we have may require some modification for use such as a hole for fiber pigtail adapter, electrical connection plates, etc... but at the same time, are also looking into making/finding a smaller box that can accomodate MAPMT and other electrical connections/fibers associated with the MAPMT. The smaller box is more convenient and would like to consider making one (provided nothing is easily found at BNL) perhaps, next week. o Tuning of the calibration systems will be done at BNL, probably at night to prevent interference with work done during the day. This also has the advantage of decoupling the tuning process with the installation process which may be done during the day. o Finally, delivery of "initial" calibration system boards to begin installing in final modules (LMs) is contingent somewhat on delivery of long fibers but has been projected to be end of next week/early following. The 24" fibers are being completed this week at FNAL and are expected to also arrive sometime next week.