Minutes for August 3, 2004 Present: CV, JC, MT, AO, DG, GR, CR, ML, LB, AR, DH, MA, JP, CJ, PM, AH, KO (recorder) Hardware Improvements/Upgrades DH: 1. Need to talk to Klaus about improving the sextapoles and magnetic quadrapoles 2. The vertical mass slits, Y slit M, aren't reading currents, Peter will look into it 3. The upgrade of the ion chamber needs to be discussed with Dave O. DO will present the interlock logic at the August 17th meeting. AO - We now have access to all of the EPIC stuff including FC4. MT - What about the MIDAS alarm? DH - Its been set up, but might not be the kind of alarm that we want (it latches). It causes a red flag, but does not stop the DAQ. Jac will talk with Konstantin about it. AR - What about the problem of reducing the reading error on FC4? LB - I'm not sure if we can trust the cups JC - There are problems with the current integrators. The left and right slits have different time integrators. DH - Mike L needs to pass along his knowledge about the PGAC to JC and CV before he leaves, which is on Friday. Electronics 1. The DAQ DH - Are we still looking at 4 weeks before the DAQ is finished? JP - Yes, help could be used throughout the process. MT - I can help. DH - Should we have a briefing next week with everyone who knows what's going on? JP - People should come at the end of the week to find out what's going on if they're interested. 2. The Germanium Detector DH - We want to find a more suitable platform for the germanium detector. AO - Are we always going to be using this detector from now on? DH - Yes, it seems to work and we own it. AO - A bigger thermos would also be a good idea for refilling it with liquid nitrogen. DH - Both tasks will be given to Dave O. Analysis 1. The 21Na(p,g) reaction DH - Will Cybele and Mike T be doing all of the analysis of the data for the 21Na(p,g) runs? MT - Yes, the (( calculation will be done soon, and the ( analysis will be done. CJ - It will all be done within five weeks. 2. The 12C(a, g) reaction LB - We must work on the normalization of the spectra, and a wobbler test is needed with the new tube. There is a student coming in September who will be looking at normalizing the spectra. But both FC4 and the charge state is a mess. DH - We also need to look at KO's data where the charge state distribution was analyzed along with the change of pressure in the target. MT - We should just focus on one state and analyze it, then compare it with the literature DH - What more is there to do in terms of the normalizing? LB - The elastic monitors are good, but there is much more fluctuations than desired. MT - We should have a separate meeting to make a game plan on what should be done next. We should pick one thing and get it done. DH - Lothar will organize the meeting. 3. The 12C(12C, 24Mg) reation JP - David Jenkins is waiting for a student, but apart from that he's just about ready to go. AR - A point was brought up last week when preparing for my presentation that the 26Na contamination in the 26Al beam would not decay isotropically, but cos ( DH - No, this does not need to be considered because theses are MeV betas, not eV secondary electrons. DH - Another thing that needs to be considered is the counting rate of the 21Na beam was different with its intensity then for the 26Al intensity. CR, can you look into it? CR - It can get done by the end of September. Publications MT - We should be able to get the information in Cybele's thesis published by the end of this year. DH - At the end of September we will check back on the progress CJ - The branching ratios of 21Ne(p, g) need to be looked at DH - This won't be solved right now, but Cybele and Uwe are in charge of looking into the branching ratios, and reporting at the end of September on what needs to get done. MT - Hopefully Drez can look into this before he leaves. DH - Commissioning papers need to be done on the useful parts of Sabine's thesis, and any other relevant experiments that have been done at DRAGON since (DH to have draft ready by the end of September). This would be a report on the stable beam reactions that we have analyzed. Also publications on the BGO detectors and a shortened version of Mike L's thesis will be written up. JDA may take lead authorship on these. Proposals 1. CV looking at 40Ca(a, g). Can be ready to present in the third week of September 2. JC looking at 22Na(p, g) and 26Si(p,g). Will be ready to present in the second week of September. 3. LB wants 27Si (p,g) to be added as well 4. JP looking at 18F(p,g) with Alison Laird. Will be ready to present in October. AOB Mike A showed some slides of the results of some SRIM simulations for the 188 keV resonance of the 26Al (p,g) reaction. Recoils were spread kinematically, and leaky beams were assumed to be at the nominal energy of the recoils. Slide 1 - No detector spread using a MCP/PGAC system Slide 2 - No detector spread using a dual MCP system Slide 3 - PGAC with a 350 pico second detector spread Slide 4 - PGAC with a 1200 pico second detector spread Slide 5 - MCP with a 350 pico second detector spread Slide 6 - MCP with a 700 pico second detector spread It was found that taking into account the detector spread, the resolution is not such that you could easily decipher between the leaky beam and the recoils The last slide presented was a simulation in GEANT to compare with the exercise done during the 21Ne(p,g) run where the slits were gradually closed. Since Ne reaction parameters were not known at the time, this was simulated in GEANT using 12C. The simulation turned out to consistently show more optimistic transmission than the experimental data. 11:40 - Meeting adjourned