MINUTES OF THE COOLER-CSB GROUP MEETING

October 10, 2001 (EJS)

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

Scintillator Status

We have asked John Vanderwerp to make 11 scintillators for CSB:

• a replacement for the melted delta-E1.
• four new delta-E1 scintillators that have a 4-inch by 4-inch active area. The foot-long light guide will be tilted by 20 degrees to avoid an interference with the Cooler beam pipe. Even so, one will have to be mounted downward to avoid conflict with the beam pipe stand. An aluminum frame will help final alignment once the detectors are in place. For this to work optimally, Tom pointed out that we need two left-handed and two right-handed light guides, and he will so inform John Vanderwerp.
• four cosmic paddles. These will be cut from longer scintillators and the end repolished. PMTs must be added.
• two luminosity detectors, one delta-E and the other E for the scattered deuterons.

Pb-glass Numbering

Chris reported that on beam left there will be Pb-glass detectors numbered 1 through 112, and on beam right the ones numbered 113 through 256. They will be sorted into 32 groups of 8 that are multiplexed to the same TDC. Chris presented a numbering assignment that has the feature that no two detectors going to the same TDC channel have less than two other detectors separating them. There will be one ADC and one coincidence register channel for each Pb-glass detector.

Running Schedule

A draft schedule is now available that places the CSB run starting in mid-January. All of December and January could be devoted to proton running on the Cooler. The only run that is certain is the run for the Michigan group immediately after Thanksgiving.

Report from the Cooler

The channel is almost all of the way in. The magnetic shield still has to be placed around the beam pipe before final placement. Ted Hall is making new Kapton windows. The Pb-glass stand is being assembled.

The was discussion of the routing of high voltage cables for the Pb-glass. This will be investigated later.

Things to Get Ready for Data Acquisition

An area called "c78d" will be set up on APOLLO. Tom will make sure that the software to run the large 1400 high voltages power supplies is there.

We will need routines to locate peaks in arrays. Tom has something with which to start. One application will be to run pedestals for the FERA modules. Another will be to set the gains of the phototubes based on the location of cosmic ray peaks. There will also need to be some simple error checks to make sure that nonsense values are not used. Files should be made that are suitable for downloading to the FERA.

The initial run objective will be to get the channel working as it was before. We will try to have the four-fold delta-E1 detector installed so that we can evaluate its performance.

We can trim the trigger to include just the 3He events by raising the scintillator thresholds. With this as a start, we then look at the Pb-glass. Approximately 1/3 of the events should se no hit, 1/3 see 1 hit, and 1/3 see 2 hits.

It will be useful to have some cluster finding software that converts hits into clusters. The fractions mentioned above really apply to clusters. We will see more Pb-glass hits as neighboring cells fire.

With position information on all the detectors obtained as they are stacked, we can also have a lookup table that converts hits (or the centroid of clusters) into theta and phi polar angles. From this information, we can develop crude readout on opening angles and other tests to confirm that the pi0 decays are properly recorded.

Tom will work with John Olmsted to get these routines going; Ed and Chris Algower will advise.