Real Photon Collaboration Engineering & Photon Beam Meeting 10/1/02 Minutes Attendees: P Bosted, R Erickson, L Keller, W Olson, M Palrang, S Rock, T Sanchez, D Walz, T Weber, C Wilder Items Discussed: 1. Spectrometer design a. Beam pipe from the LASS wedge thru the detectors will have a strongback system for lead support and alignment. A 0.06-inch thick plate will connect the strongback beams and center the tube. Final details are close to being worked out. b. There will be no poly in the central horizontal plane area from the LASS wedge to the middle detector. c. Beam pipe thru the graphite in the D3 magnet will be an oversized hole of approximately 4 cm in diameter. The graphite will be in the D3 vacuum chamber. d. T Weber and M Palrang are incorporating piezoelectric movers into the target system. e. A new adapter will have to be designed to mate the new D3 vacuum chamber with the D2 vacuum chamber. D3 will be relocated 7 cm south to be on beam centerline. 2. Compton polarimeter: P Bosted wanted the septum and magnet moved as close as possible to the collimator, and will check it out for signal problems. It will most likely require a long taper on the upstream end of the septum. 3. R Erickson said nothing would happen on the switchyard equipment for at least 6 weeks. After that any work would be on a manpower availability basis. Decisions Reached 1. See items 1 and 2 above. New Action Items 1. P Bosted will determine the septum taper, and check out moving the septum closer to the collimator. Ongoing Action Items 1. T. Weber will get prices for cast copper and tin. 2. P. Bosted to determine material to be in front of the middle spectrometer detector panel. (Complete 9/3/02) 3. J. Weisend will work with D. Crabb and R. Principe to develop a detailed drawing showing the dilution refrigerator and the proposed superconducting magnet. 4. P Bosted will continue the physics simulations of the proposed change to the RPC design. (In progress) 5. The interaction of the LASS magnet and all its iron with the E161/ E159 7-T target magnet needs to be carefully modeled using a 3-D field simulation. (Complete) 6. Shielding and earthquake supports associated with the LASS magnet must be evaluated and designed. This action item was re-written and M Olson is working on it. (In progress) 7. T. Weber will investigate other E160 target materials to replace the Pb and Au for example Tantalum or Platinum. (Complete 9/3/02) 8. L Keller will identify all forces on the magnet system, and confirm the magnet configuration. Adding whether re-positioning the wedge can zero the force on the wedge. (In progress) 9. S St. Lorant to give L Keller the LASS current decay time constant, so Lew can calculate forces. W. Olson