From: KEKUX::"FRAUTSCHI@UNMB.BITNET" "Mark Frautschi, The University of New Mexico" 27-SEP-1994 05:14:55.63 Subj: Executive summary of September 1994 TRIUMF E675 run. Dear E675'ers, Here is a collection of information on the recent run, the possible January 1995 run, and delays in returning irradiated samples. Please read Kathy's note at the bottom regarding this last item. Mark -------------------- re: summary of recent run --------------------------------- The following is a summary of the recent TRIUMF radiation damage run. TRIUMF 1B beamline, September 7-12 1994: 9 cm x 9 cm 500 MeV K.E. protons M.F. arrives Sunday 4 September. 9 x 9 cm collimator in place (surveyed). Tuesday, September 6th setup begins in ernest. Everyone gets indoctrinated to radiation safety, gets keys, etc. Everyone is busy setting up. Beam scheduled from 8:30PM Wednesday the 7th. Need to find ion chambers and beam box. Beam box never found. Wooden frame replacement built by Benn Tannenbaum and Tim Collins. Additional concrete craned in to Ib cave. Requires lifting of 54 ton roof blocks. Loose one day to craning and inspections of 50 ton rated crane. Warm "box" and cold box and collimator re-aligned by theodolite after collimator was bumped by crane crew. Polarimeter, ion chambers calibrated Wednesday. Lenny calculates 45 X 10^6 L+R polarimeter counts = 10^13 p+/cm^2 at slot 1. Approximately 1000 L+R polarimeter counts / 2.5 seconds corresponds to 1 nA of beam current. Begin running at beam currents of about 0.5 nA and three eight hour shifts of two people each per day. About 1/8 of conservative beam current average for last year. MCR reports high n0 levels in Meson hall. Can run at 1 nA in evenings (6PM-6AM) if hot areas in Meson hall are roped off. Suspect that removal of the 1B beam dump (p+ now hit the concrete wall) may contribute to raised n0 levels. Adjust beam uniformity using profile monitor. Looks like about 30% fall off at edges. We measure the absorbtion in the stack with three 2" x 2" foils. On axis we are down to about 60% after 20 warm boards (1 inch spacing) and to 38% after the 18 slots (2 cm spacing) in the KEK cold box. Fit to r^-2 and linear term. Continue low currents through Thursday the 8th and during the day on Friday. We reach 10^12 p+/cm^2 and pull the first (Sung Han's) board. Reach 0.25 Mrads On Friday night a new Shift Crew comes on and gives us 5 nA of beam. We decide to keep quiet and see how long this will keep up. Another shift notices the discrepancy on Saturday PM. They do a survey with "snoopy" the portable n0 counter, and find no hot spots in the hall. They ask us what we changed in the stack. as far as we know, nothing substantial. Perhaps the beam uniformity adjustments made earlier reduced the n0 levels. Reach 0.5 and 1.0 Mrads at slot 1. At approximately 6AM Sunday the polarized source breaks down. At least 24 hours to repair older source (Warm up / cool down cycle for primary source is 48+ hours). Get beam again mid-Monday. Run extended to 6AM Tuesday. Total fluence for slot one was 311,365,000 L+R polarimeter counts. That's 6.9 x 10^13 p+/cm^2 or about 2.3 Mrads. Benn Tannenbaum's G10 board exhibits a uniform darkening centered on the beamline, an indication of accurate beam placement. Fluences to be confirmed with final foil activation measurements for each board at FNAL facility. All detectors and samples bagged by institution and placed in 0 degrees C freezer to deactivate and await shipment without antiannealing. (CDF ACTIVE board left at room temperature per Eric Kajfasz's request.) Micron detectors got scheduled fluences of 0.25, 0.5 and 1.0 Mrads per Daniela's notes (Contrary in some cases to what was printed on the detectors themselves.) SINTEF/SI detectors get a similar course of fluences. CDF SVX II Mechanical (Fluids and Epoxies) boards got over a Mrad each, half of what was requested. Unfortunately, the LBL, UCSC and KEK people got less that they wanted. Kathy O'Shaughnessy begins assay with TRIUMF Safety Group and Shipping regarding refrigerated samples and foils Tuesday 20 September. (See her note below.) Canadian Atomic Energy Control Board requirements (unbeknownst to E675 and TRIUMF Safety Group until 9 September 1994) require a detailed application (listing activities broken down by isotope) for each shipment to each institution be made. These were completed on 14 September. It is not clear how long it will take to have them processed. (See Kathy's note below.) There has been a cancellation for some 1B work for the first three weeks in January. We can probably get another E675 run out of it if we want it. (No need to form a new collaboration or proposal, however we would need to request it. See e-mail to Dave Hutcheon and his reply appended below.) Dave Hutcheon also says that TRIUMF are interested in learning the long term "demand" for radiation damage studies. They may be interested in creating a dedicated facility. Mark Frautschi (505) 277-2090 frautschi@bootes.unm.edu P.S. Temperature of the cold box was operated at -1 to 0 deg.C during the exposure.