DRAGON Meeting  20 June 2006

Present  DO, (rec) EOC, DH, PM, CD,LB, AH, JZ

Hardware
      We are in the middle of a power outage.  DRAGON did not suffer too
      badly,   The trap was allowed to warm up over night.  ED2 is still on
      at 50 kV.
     DRAGON is in a resting state until JP returns to do alpha studies with 
     EOC in about 2 weeks.

Evan O'Connor.  GEANT Simulations.
    The ED's have a more correct representation with field clamps in GEANT
    The MD's have vacuum vessels now.  Clear gap in MD1 is thus reduced 
    from 10cm to 8cm.
    Simulation of alphas shows losses in the vertical dimensions in the
    triplet and Q6 and Q7.    Less loss with C recoils  and 93.6 percent 
    transmission.
    To do:  add mapped fringe fields to the dipoles.

Joel  Zylberberg    Charge state studies  
     Our best model had assumed no pick-up of the He electrons in alpha capture by
12C beam at 1.068 MeV/u, but it still underestimated the fraction of 6+ recoil
oxygen ions at low target gas pressure.  The model was extended to allow a
small fraction of 3+ (Li-like) C ions to form 6+ (He-like) O ions upon capture,
in addition to the 5+ (Li-like) formation of the original model.  This gives a
better account of the ERNA 6+ data without destroying the agreement with our
6+/5+ ratio data, for a 90:10 ratio of 5+:6+ O ions following capture of a 3+ C
ion.  (See attached figures.)
    We have no quantitative explanation for such a ratio.  Factors may include
impact parameters, atomic shell (binding energy) effects.  Possible further test
is to use attenuated beam, low gas target pressures, and compare the scattering
into the 10-20 mrad wings to the total beam as a function of charge state.

 C Ruiz        CAP Report
    There were 2 astrophysics talks of interest.   
  MSU
  o Looking at excited states of 30S and 31Cl from (p,d) reactions at S800
  separator. Measuring gamma-rays. Get excitation energies to ~5 keV.
  Preliminary results. Plan to do 26Si and 36K.
                                                                                
  Oakridge
  o 7Be(p,g) using Daresbury separator and Uwe Greife gas target. Also did
  (p,p') with SIDAR arrays - inelastic channel noted to be strong.
  o 18F(p,a) data shown, looked like the same data as in A. Laird's 
  proposal.
o Also looking at 19Ne states via 18F(d,n) - investigate single-particle
strengths.