From giglio0@unbc.ca Fri Jan 25 17:47:35 2002 Date: Fri, 25 Jan 2002 02:31:57 -0800 From: Dario Gigliotti To: Dave Hutcheon Subject: Jan 22, 2002 Minutes Dragon Group Meeting : January 22, 2002 Present: DAH, DO, JR, LB AC, DG, AO, SE, SB, MC 1) Business Arising Deadline for abstract submission to EMIS conference is Feb 1, not Feb 14 as stated in Jan 15 minutes DO has removed the wobbler magnet and put the gas target back in. After a survey it was found that the apertures are ~1.25 mm off. BCM 1 was found to be ~1.25 mm PM is looking at BCM 6 CW is trying to come up with two different thicknesses to span the energy range of the elastic monitors. There was a suggestion by AO to use a second Si detector for beta separation. Elastic monitors may need to be reordered as a noise problem is overpowering the rise time. Installation of the MCP will be starting today (SE). The goal will be to get at minimum a time signal in the next run. DSSSD needs to be remounted. Currently attached to the lid. ED Units Scaling program can now read newer files. Lead shrouds are still being constructed, painted, etc. 2) Summary of Wobbler Runs. Presented by SE. (see attached PDF for details) Results of tests for magnetic rigidity for various masses was shown A summary of various combinations of matrix element values and their effects on beam focus at different focal points along DRAGON were also shown. There is still some concern over what the input angle of the beam is. It was noted that there needs to be some way of finding out which of the last RIB runs had the correct input direction. JR suggested that fluctuations in bogie rate vs. run number should be looked at. Results also indicated that system is showing a 10 mrad acceptance rather than 20 mrad expected. 3) Objectives/Suggestions for Coming Run a) Find stable beam reaction with same opening angle as RIB run and vary settings to verify no changes. This will help to confirm which data can be used. b) System acceptance/efficiency. OLIS says L-Bend used for Mg production may not be available at beginning of next run c) Understand origin of leaky beam d) Calibration of beam at higher energy. AO suggested there may be an 16^O point that is useful. e) BGO vs. Recoil efficiency f) Timing measurements with MCP g) Buncher? 4) Analysis Reports: a) 21^Na, 220 MeV Presented by SB. (see attached pdf for details) HI = Heavy Ion CG = Coincident Gamma Cuts were determined by first plotting all of the HI TOF events VS HI Time events (top left plot) that simply pass the requirement that their assiocitated HI energy and CG energy be greater than 0. Top right plot...zoom in on events clustered around 7400'ish in the vertical channel. +-1% around the average channel value that the points fall on, and accept those events that fall into that range. Middle-left plot: Shows HI TOF VS HI Energy to see what, if any correlation there may be. Not much, as the Si detector resolution (6%) causes too much scatter. Middle-right Plot: Just HI Energy VS CG Energy. There is a low lying event that looks suspicious. Lower-Left Plot: Same plot as top right, only now with a cut on it to require that the CG energy be larger that the CG energy of that low lying guy in Middle-right plot. Check to see where in the HI TOF that suspicious event's HI fell. It's in the middle, so it's not one of the events on the outer limits of the +-1% HI TOF criteria. Lower-Right Plot: Histogram of the gamma energies of the 8 events in top right plot, along with the gamma energy of the "suspicious" event. Note the suspicious event's CG energy is below 3MeV, so it is not counted in the final tally of "good recoils". Result is 8 recoils in that run. There is the possibility that runs 4892 and on had DSSSD damage and may not be recoverable. SB will check. b) 21^Na Resonance, 865 MeV presented by AC (see attached PDF for details) A graph of yield vs. energy for this resonance was presented. Analysis looked at singles only. In the graph the circled points represent beam energy reproducibility problems for 865 energy. There were also points at 880 and 840 MeV with very good reproducibility for different run numbers. c) DAH replay of data shows a possible electronic problem apparent in a time of flight spectrum. (See attached PDF) d) JR presented material, which will be given to Alan Shotter for EURISOL conference (see attached PDF for graphs and description of graphs) [ Part 2, Application/PDF 163KB. ] [ Unable to print this part. ] [ Part 3, Application/PDF 10KB. ] [ Unable to print this part. ] [ Part 4, Application/PDF 4.8KB. ] [ Unable to print this part. ] [ Part 5, Application/PDF 5.5KB. ] [ Unable to print this part. ] [ Part 6, Application/PDF 27KB. ] [ Unable to print this part. ] [ Part 7, Application/PDF 92KB. ] [ Unable to print this part. ]