Real Photon Collaboration Engineering & Photon Beam Meeting 9/17/02 Minutes Attendees: P Bosted, L Keller, W Olson, M Palrang, S Rock, S St Lorant, T Sanchez, D Walz, T Weber, C Wilder Items Discussed: 1. Spectrometer design a. Beam pipe to have 1-2mm wall, and can be made of stainless steel or aluminum. b. Lead shielding around the beam pipe is to be 2 cm thick and can be split on the horizontal centerline. c. Structure can extend in to the beam pipe on the horizontal axis for support and alignment. Beam pipe alignment must be within 0.5mm. 2. Bruno is back working on the DC2 alignment stage design and SEM for the goniometer. 3. Who is to design the support structure for the wire array and toroids is to be determined. Bruno will be available after he finishes the work in item 2 above. 4. Compton polarimeter a. The design should be as close to the previous experimental configuration as possible. The vacuum chamber through the magnet will need to have sidewalls as thin as possible. b. Bellows on both ends of the collimator is required for critical alignment. c. If mirror plates aren't used, then the septum will have to be much longer. This will also move the magnet down beam from its current location. Today, 9/18/02, S St. Lorant found a picture of the previous experiment, I think it was 154, which showed there were no mirror plates. d. P Bosted will determine if the septum needs to be tapered. Decisions Reached 1. See items 1 and 4 above. New Action Items 1. P Bosted will determine if the septum needs to be tapered. 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) W. Olson