DRAGON meeting minutes April 1st, 2003.   
 
Present:  Dave Ottewell, Dave Hutcheon, Catherine Neish, Zhihong Li, Chriz Ruiz, 
Fred Sarazin, Aaron Bebington, Joel Rogers, Lothar Buchmann, Sabine Engel, 
Cybele Jewett, Dario Gigliotti, John D'Auria, Uwe Greife, Chris Wrede (scribe). 
 
Chris Ruiz was introduced to the group.  He is employed by LB.  Welcome, Chris. 
 
 
Hardware, Software Updates:  
 
DH: New Faraday cup FC2 installed in mass slit box, parallel to existing Faraday 
cup FCM and 12cm off center on "low mass" side to monitor beam intensity of selected 
charge state while running.  Needs to be output to Epics and Midas.  JR will free 
a rarely used Epics scaler channel. 
 
DH: Need to warm trap at some point for transition from hydrogen to helium target.  
12C(a,g) starts Thursday, Apr. 3rd (see run plan below). 
 
AO: Tune scaling program has been improved.  AO will test it today/tomorrow. 
 
DO: A large volume buffer tank has been added to the backing line to increase its 
volume (and keep pressure low for longer periods), and allow the backing pump, BP31, 
to be turned off for long intervals and increase its lifetime.  BP31 will turn on 
automatically when pressure gets too high.  Commissioning in progress.    
 
DH, LB: ED conditioning is a concern for 12C runs.  Conditioning program takes ED2 
above 120kV.  For ED2, the program kicks out after each 3-4kV increase.  Maximum 
voltage on ED2 is marginally 130kV, this needs to improve. 
 
DH: FC1 problem fixed by PM, it was plugged into the wrong spigot. 
 
UG: Showed a typical ionization chamber Delta-E-E plot for 13C(p,g) runs.  14N recoils 
were clean.  It was compared with a Delta-E-E plot for attenuated 13C beam at the same 
energy.  The two were well separated, but a low energy tail was observed for the recoils.  
ML will analyze the data for yield.   
 
UG: Ne21(p,g) will be run today.  Note added in proof: op's couldn't provide beam.  
 
 
12C(a,g) run plan outline (LB):   
 
For the plateau between the two 4+ resonances  (1.07 MeV/u and 1.31 MeV/u) a cross section 
of 30 nb for the cascade 6.9 MeV transition is as low as it gets. For a 100 pnA beam and a 
1x10^18 cm^-2 target this amounts to 65 events/hour times efficiency (~40%), i.e. 26 events/hour. 
For the ground state transition the cross section is of the order of 1 nb, i.e.about 1 event/hour. 
 
As practical life goes, an energy change in the morning with data taking starting in the 
afternoon till next morning would be proposed. The general idea would be to gradually increase 
the energy by steps of 10 keV/u. 
 
Therefore 1.07 MeV/u shall be the first energy to test the system. Then 1.08, 1.09, 1.10, 1.11, 
1.12 ... MeV/u.