MINUTES OF THE COOLER-CSB GROUP MEETING

November 26, 2001 (EJS)

Present: Chris Allgower, Andy Bacher, Chris Lavelle, Hermann Nann, John Olmsted, Tom Rinckel, and Ed Stephenson

REVIEW:

Minutes have been missing for the past month or so as people worked in the Cooler to finish the setup. Last week, Tom Rinckel declared the effort successful. Briefly, the tagger detectors and stands were removed and packed away. The old target box was removed and replaced by the new one. Internal apertures were aligned and the nozzle position was checked warm and cold. Pumps were replaced and all roughing lines rerouted. A magnetic shield was put around the coils on the 6-degree magnet to cut down on field in the neighborhood of the Pb-glass detectors. Two large stands were installed, each with a moving table to hold the Pb-glass. The Argonne and IUCF detectors were stacked, more than once, on either side of the beam. Positions of all of the detectors were recorded. Cables were strung for high voltage and signal, going to patch panels previously wired to connect to amplifiers and discriminators. Chris Allgower organized an effort to reduce noise on the signal lines and set zero offsets on the amplifiers to get reasonable pedestal voltages going into the FERA ADCs. The ADCs and coincidence registers connected to discriminators now can be read out into the computer. Cosmic ray events can be triggered based on a coincidence between long scintillators placed across the Pb-glass detector stacks on the top and bottom. Work has started on the software to interpret cosmic data for pedestal and gain information on each detector.

The goals of the access time during October and November have been accomplished. As of tomorrow (11/27), the Cooler will close for running. Several small items remain to be done, including FERA readout of the Pb-glass time signals, installation of the first MWPC, wiring all MWPCs, installing the luminosity detectors (the delta-E and E are ready), installing delta-E(1), and connecting spin bits for polarization monitoring.

ANNOUNCEMENTS

• There is no word from the NSF on the size of the Cooler operating budget for 2002. So we will not write a schedule for January (when we expect to have a proton setup run) until later. We hope to have final information before the Christmas break.
• John Cameron has called for a Program Advisory Committee meeting to discuss strategies for Cooler running under various budget scenarios. The meeting will be Monday, December 17. All of the active Cooler experiments will be asked to present their state of readiness and running plans. The members of the committee will be Willem van Oers, Werner Tornow, and Alan Krisch (outside user representative).
• The theorists now have a Web site. A link is provided on the IUCF CSB Web page. The only new information there is a writeup on the "homework problem" that is supposed to allow each calculational scheme a point of reference to test their techniques against an analytic solution.
• There is a call for contributions to the IUCF Annual Report. We plan to write up the two runs, polarization testing from February and the channel tests in May. Ed will circulate drafts later in the week for comment.

ACTIVITIES IN THE COOLER

All Pb-glass detectors now have usable pedestals. A particularly aggravating source of AC pickup was traced to the transformers that power the CAMAC crates and sit just above the delay boxes inducing currents in the coils of delay cable. Several layers of mu-metal reduced this for most lines. The remaining lines were terminated capacitively at the FERA input. All of the extra large Pb-glass detectors stacked high and low appear to have AC pickup from the PMT bases. This was also removed with capacitive coupling.

Work is still needed to separate the gate for timing FERAs from the pulse height FERAs.

The luminosity detectors are ready to mount, as is the single delta-E(1). The smaller 4x4 delta-E(1) detectors are still being glued to the PMTs, consuming the last of the new PMTs bought for CSB. They will need to be wrapped and tested. No mount has been devised. This also used all of the 0.032-inch scintillator stock. It was decided to make a replacement order in case there is ever a need to repair one of the delta-E(1) scintillators. The cost is $600 for a 12 by 18 inch sheet.

There was discussion of the status of cosmic ray event handling. Events are triggered at the rate of about 1/second. With some loss in statistics, it was suggested that gain setting should look at cosmics that pass vertically through the stack, hitting all detectors in a column, for example. It was also pointed out that with the present multiplexing scheme, detectors that are above each other are routed to the same timing FERA channel, thus creating an ambiguity when binning time information. It was suggested that diagonal tracks could be used without changing the present wiring configuration. For cosmic ray running during December, there will be no timing information. This still allows people to work on the schemes for obtaining and downloading pedestals, and making adjustments to the gains of the Pb-glass PMTs.

A question was raised about the amount of absorber needed in the luminosity detector system, and whether it made sense to plan for a veto detector at the end. Energy loss calculations are needed.