June 21, 2005, 10:45 am Minutes for DRAGON Meeting Present: John D'Auria (JDA), Jac Caggiano (JC), Christof Vockenhuber(CV), Anuj Parikh (AP), Mark Huyse (MH), Lisa Fogarty (LF), Chris Ruiz (CR), Mike Trinczek (MT), Thomas Kirchner (TK), Jonty Pearson (JP), Benji Wales (BW), Bing Guo (BG), Art Olin (AO), Dave Ottewell (DFOT), Alison Laird (AL), Chris Wrede (CW), Goetz Ruprecht (GR), Simon Fox (SF), Paul, Heather Crawford (HC) - recorder. 1. Minutes of June 14, 2005 meeting: No changes. 2. DRAGON Hardware: Status of Systems: DH: There was a problem with the cyclotron beam onto the target fluctuating, which turned out to be related to a problem with the RF booster, which was discovered and solved yesterday; the proton beam on the target is now much more stable, so problems with the current creeping up should now be eliminated. MT: Was the operations group not aware of this; is it not something they check? DH: They are now aware, and are adding this to a checklist. Operations group also wants to do maintenance -- there is a problem with the quad magnets which will require 3-4 hours maintenance starting tomorrow (June 22) at 9:30 am. Marik has also requested more time for yield measurements and beam adjustments, likely on Thursday. This will need to be discussed more, to decide where we stand, at end of meeting. JDA: They also need to retune the beam in the mass separator area (problem with slits), to solve problem with slits; this should not affect DRAGON tune. 4. E989 Status CR: So far things are running smoothly. Didn't start with the intensity we want, initially had 40 epA on DRAGON target on Thursday, then with the laser some gains were made on Friday (mass scans showed 26Al peaks with broad humps, due to laser being focused incorrectly, so gains were ~ 2X, not 25X as initially hoped). Therefore, on weekend, were running ~ 100-150 epA on DRAGON target, using CR and AP's tune from Thursday, which might not be correct compared to DH's tune. Have seen 3 coincidence events so far. See attachment. First plot is BGO energy vs. DSSSD energy, plot on the right of this is the BGO singles spectrum and the plot on the bottom is the DSSSD singles spectrum. In the DSSSD singles spectrum, the events fall just below the leaky beam energy as expected (the source of the high energy peak is unknown); in the BGO singles the large peak at 4 MeV is suspected to be related to 26Na decay - MH. DSSSD energy versus local TOF plot also shows recoils well separated from the mean leaky beam. The DSSSD-RF could also be useful (at least 2 events fall together on this plot). CR: Are currently seeing ~ 10X less 26Na in beam compared to last year, which can't just be due to the use of the laser. DH: 26Na contamination level probably has something to do with the target temperature. CR: 3 events seen look good on local TOF spectrum as well (see attached) -- all 3 events line up within 2 channels; appear ~ 250 ns slower than 25Al recoils in 24Mg(p,g) reaction. Also in BGO spectrum, appear at similar energies. However, all are grouped upstream in the gas target, but there are only 3 so far. Running gas target at ~6.15 Torr. The yield is reasonably close to expected so far. MT has set up spreadsheet on isdaq03. All runs should be added into spreadsheet which calculates the average FC4 reading and uses this and run time to determine the total beam particles and yield. Any coincidences observed in a run should be checked against requirements for a real event in ELog, and if a real event is seen, it should be entered into spreadsheet. This will be added to the list of things to do while on shift. CR: The BGO threshold is set to 1 MeV; the efficiency is higher than we think due to a 3-gamma cascade; GEANT simulations will confirm this. AO: Leaky beam suppression seems good; there aren’t many random coincidences. 5. Problems while running... CR (& AP): Over the weekend, an error came up a couple of times on MIDAS; runs were stopped, and then started, and the error was gone. JP: Error is not related to data-taking; has to do with MIDAS web interface. To solve, just start the DAQ again (don’t need to stop DAQ, restarting only starts any processes that had stopped). MT: In the run log, some runs had two lengths (same start time, different end time, ~ 4 minutes later). --> Might be connected to ELog corruption problem JDA: ALWAYS fill out run sheets! --> Run sheets are important for catching drifting elements, though the history is also useful. JP: The tuning instructions on the web do not seem to match what DH actually does. --> JP and DH will sit down and clarify instructions. 6. AOB JDA: The TRIUMF summer school is coming up starting July 11, 2005 for 2 weeks. Students are recommended to sit in on the lectures. 7. Scheduling of Maintenance etc. JDA: Marik wants the beam on Thursday; seemed to imply factor of 2 more was possible; wants beam for 8-12 hours. CR: We’ve already lost time and been running with lower intensity than what we wanted, and we’re going to lose more time during the days this week -- don’t want to give him as much time as he’s asking for. DH: It looks like we are going to confirm the previous yield result, so statistics is important; we don’t want to give up too much time now, when we don’t really know what we need. CR: We want to use the beam now while it is running smoothly, not take the risk of something happening to the target in a couple days. Meeting ends 11:30 am. After meeting, CR and JDA discussed situation with MD. MD may get some time on thursday to measure Al25 yield.