Status of the Crystal Ball A.Starostin UCLA

Tasks in preparation for the polarized target experiments CB and the “cube” will be movable on rails – all CB electronics to be mounted on the cube: – New electronics design for the electronics layout – The high voltage and the signal cables should be dismantled from the cube – Shorting of the signal cables, this will reduce weight load on the cube, also less delay and less signal attenuation in the cables – The all signal cables should be tested and fixed (about 10% broken DIN connectors) – The CB, PID, MWPC and trigger electronics should be moved to the cube – The detector and the electronics should wired, tested and possibly calibrated with a radioactive source

New electronics layout CB Splitters CB Discriminators CB ADC GeSiCA’s and TDC’s Trigger logic (energy sum) CB High Voltage PS

Modification of the signal cables There are meter-long signal cables organized in groups of 8 – totally 92 bunches New cable length was determined to be 10 meters (half of the old length, weight reduction ~350 kg) 46 bunches were cut in half giving us meter bunches New connectors were soldered: wide 34-hole connectors to the one half of the bunches, and 8 3-pin DIN connectors to another half of the bunches

All Cables are Done! Our great cable task force: – GWU students: Joseph Asercion, Albert Jones, Alexey Strakovsky (supervisors: Bill Briscoe, Igor Strakovsky) – Mainz: Alexander Kostikov (technical support and expertise) – UCLA: Milorad Korolija, Alexander Lapik, A.S What was done: – All signal and high voltage cables were dismantled from the CB – 46 bunches were cut in half – 46 new wide connectors and 368 DIN connectors were soldered – All cables were tested (including frequency response test and impedance measurement for each wire) – All bad and suspicious connectors were fixed (up to 20% of all old connectors) Result: – We have 92 bunches of signal cables ready to be mounted to the Crystal Ball

Jobs ahead The goal is to have the detector ready for use one month after it is mounted to the rails (by end of November on current schedule): About two weeks will be needed to wire the detector and relocate and wire the electronics Modifications to the trigger part of the electronics? (John Annand) A source calibration would be desirable. This may take another 2 weeks. (we will need functioning DAQ for that) The Crystal Ball environmental control system will be updated: four shock sensors will be included to the system. Manpower is needed for the end of Octorber-November: CB wiring (4-5 people) and the source calibration (2 people)

Temperature, pressure etc A vacuum leak of about 1.2 torr/day in the top hemisphere remains the most serious problem of the CB environment Careful constant monitoring of the pressure and the vibration of the frame will be required during the run with the polarized targets New emergency procedures should be developed assuming a sudden large leak in the detector as a results of the moving, or/and vibration caused by the polarized target equipment. Such procedure should include emergency shutdown procedure for the target heavy pumps.