Minutes from DRAGON meeting of May 16, 2006

Present: LB, JZ, CD, JP, GR, DH (recorder), DO, AH, PM

1. Minutes of previous meeting
	Were distributed just before this meeting.  No comments.

4. 12C(a,g) BGO singles analysis (DH)
	One run (16889) had the 3.5-6.9 MeV cascade standing out clearly 
above the background in BGO singles spectra (1st figure of attachment).
A cut on g0 and g1 energies selected a narrow peak in the gamma-r.f. time 
spectrum (lower half of 2nd figure); the dominant peak in the non-gated 
spectrum (upper half) seemed to be related to beam hitting ~20 cm upstream 
of the middle of the gas target.  The 3rd figure compares singles and 
coincidence gamma-rf spectra, confirming the identification of the 
12C(a,g) events.  The 4th figure, upper left, gives the BGO leading-gamma 
spectrum when gated by cuts on gamma-rf time, g1=3.5 MeV and number of 
struck BGOs=2.  The upper right spectrum is for coincidence events, but 
otherwise has the same cuts as the left-hand singles spectrum.  The bottom 
left panel of figure 4 estimates the background events, assuming that 
recoil-gamma coincidences are 37.5% of the gamma singles for this 
resonance in 12C(a,g).  
	With an assumption of 12C beam being 47.5% in the 5+ charge state 
and DSSSD detector efficiency 96%, initial analysis gives 82% transmission 
through the separator (uncertainty at least 5%).  
	
	Priority will be to do GEANT simulations to match the above 
analysis cuts for this resonance.  In parallel, a detailed model is being 
developed for the evolution of charge state distributions as beam and 
recoil particles pass through the gas target.

2. Ti charge state distributions  (DH for CV)
	We obtained all the essential data, at all but the lowest of the 
energies on the list.  It was hard to get a Ti beam after OLIS had run C 
beams for many weeks, but finally a good beam (0.4 to 1.2 enA 9+ 48Ti) was 
accelerated starting on the weekend.
	There is some evidence of gas leaking behind the CSB foil.

3. Hardware/software status & plans
	- new display manager: JP still communicating problems with fonts, 
etc. to Jane Richards, as found in his private version.  The thermocouple 
numbers show only with the new GUI, so they could trip the Roots blowers 
and we would not know why with the old GUI.  Decision: we will ask to have 
the new display manager installed for DRAGON and hope to get problems 
ironed out before we run again.
	- isdaq04 will be upgraded to 'site standard' Scientific Linux 
from current Redhat O/S.
	- last night there was a problem with Inlet buffer pressure 
reading going to 1000 Torr, because the controller was saying 'no sense' 
due to cable coming loose from the capacitive manometer head.  
Cable-wiggling fixed it, but more secure attachment is needed.
	- iris worked OK for 12C(a,g) but still needs to have a linear 
slide repaired.  The next 3-4 weeks may be clear
	- acceptance study plan calls for hardware to allow DSSSD to be 
mounted on the Interceptor drive, for acceptance work with alphas.
	- the 'Faraday cups reading current' red-flag messages in Midas 
get tripped when cups are pulled out but left on the 3uA scale.  Cure is  
to get more useful scales in the gap between 100nA and 3uA?
	- consider getting a wireless laptop for working around DRAGON? 
(How to keep it from wandering?)

5. For next week's agenda
	- plan for next alpha work (JP)
	- CSD simulation  (JZ)

Meeting ended at 14:37