DRAGON meeting  March 15, 2005


Present: AL, DG, CR, MT, JD'A, LB, GR, PM, DH, AO, guests
         (JC, CV, DO came late)

1.  Waiting for DO, JC, JP ...

2.  Minutes Approved with no changes

3.  DH reports on ED1
   o  conditioned up to 165KV
   o  when it trips, starts again at 155KV
      -  not clear what causes this
   o  ED1 anode driver seems trip off for no reason
      - no alarm for this, so have to pay attention
      - procedure in the notes.  n.b.  back off Voltage first

   ACTION:  setup an EPICS alarm for this !!  MT will ask Konstantin

   o AO suggested a strip-chart could help us monitor and diagnosis problem  

4.  DH reports on Na23 beam fun

   o  seemed that two simulataneous energies coming out of DTL
      -  apparently due to  phase mistuning prior to DTL
      -  the PRAGUE magnet measured 312keV, but DRAGON saw only 258 !!
      -  this due to mistuned HEBT systems into DRAGON

   o  everyone now aware of this possibility
   o  new s-bend magnet has complicated matters
      -  must pay attention to measuring our own beam energy  

5.  23Na(p,g)  measurements at 312 KeV
   
   o  DAQ at one point didn't work for DH, JC, et al, but then worked for JP
   o  seemed that low energy tail from beam mistune caused lots of BG  
      -  didn't see as many coincidences as expected, now understood as an 
         acceptance issue
   o  lowered Ebeam by 15keV, now see _no_ coincidences (good, apparently)
   o  group now playing with new SiN CSB at exit of gas target
      -  will do CSD with/without it
      -  "should" handle 4Torr
      -  not in EPICS
      -  has _not_ seen beam yet


6.  J D'A  notes that DAQ system is new
   o  emphasizes that people should go over to play with it
   o  LINUX and ROOT-based
   o  waiting for summer student in May to write user manual


7. J D'A  reports on cyclotron troubles
   o Still a leak in cyclotron, but don't know where in upper resonators
   o so things are two weeks behind schedule
   o 'dose-takers' may be necessary to assist with finding leak in main tank.


8. MT discussed 'alternate production' progress
   o  11C made at TR13, separated in chemistry group, put in a cold trap, 
       and brought over to ISAC test stand in proton hall extension
      -  using older ECR of similar design to ISAC one
   o  first learning how to use ECR, testing gas loads, etc
   o  practised in the past with 13C
   o  got permission to do this test with 11C with tens of mC activity
      -  yield curve of Mass 11  w.r.t. time shown
      -  sampled lasted 70 minutes or so
   o  second 35 mCi sample made, slightly different ECR and flow adjustments
      had much better yield (this time M=27, i.e. 11C16O)
      -  overnight run showed 21' half-life
   o  scratched their heads trying to get efficiency.
      - following some procedure, got 1.8%
      - absolutely no optimization
   *  important thing is that NOW they are getting 10^7 particles/s  with 35mCi
      -  with higher specific activity around 1Ci, should get 10^8, enough
         to do an experiment. 
      -  also system needs to be further optimized

   o  J D'A suggests a report to the ISAC forum group, and the EEC
 
   o  what to do next ??


9.  CV reported on SiN CSB test
   o  foil boosted 300keV 23Na beam CS from 5+ to 6+
      foil is located just downstream of the inner gas target cell

   o    GAS only       SiN only   SiN+gas
     ------------------------------------
   4      1.36          0.23       1.17
   5      1.71          1.02       1.42
   6      0.73          1.75       0.52
   7      0.11          1.06       0.07

   o  yikes!  seemed that gas downstream of SiN reestablishes gas CSD !
      -  0.2T downstream of foil
      -  must somehow remove/reduce that downstream gas
         *  make window bigger and move it downstream ? 
   o  much discussion about what to do next


10.  DH on 20Ne(p,g)21Na run
   o  starting with commissioning, DRAGON always below published results
      -  latest:  3sigma lower
   o  DH looked back at 1964 experiment
      -  seems that _their_ yield and stopping power doesn't give _their_ w*g
   o  reaction IMPORTANT as a 'normalizing' tool for other reactions
   *  so a "real" 20Ne run establishing a defensible number is _publishable_
      -  must be a 'disciplined', not a slap-hazard, run
   o  20Ne beam starts _this_ THURSDAY for 4 days
      - focus on getting a good number
      - important to get good normalization
        *  use elastic monitor
      - detailed run plan needs to be made

11.  DG reports that on website there are notes on how to produce simulated 
     efficiency numbers for the BGO gamma array, used in his thesis

12.  Commissioning paper being polished by DH and almost ready for submission 
   

meeting adjourned 11:55