DRAGON meeting minutes july 27th 2004

Those present: CV, JDA, JC, CR, MT, KO, AR, KELLY, AL, GR, DH, 
	UG, LB, WL, JP, PM, AH, AO, DG, CJ, MA, ML (Thoth)

1. Business arising:

CR  - The target failed during the 26Al resulting in no beam.
    - Could not put voltage on source and were unsure where the problem was.

UG  - There were problems with the electronics between the 21Ne and Al runs. 
      In particular a coincidence unit was ill.

JC  - We need fans to cool NIM modules. JP will look into.

2. 21Ne run results:

KO  - Goes over her calculation of the omega-gamma, see the first attachment.

    - The partial yelds were measured directly with different charge states. 
A change over last week is the calculation of the partial yields shown 
on the first page.

    - The calculated omega-gamma is 118 +35/-11 meV. This should be compared
to the previously published result of 82.0 +- 12.5 meV.

    - The asymmetric error bar in our result stems from an unexpected
asymmetry in the number of counts at the end detector in coincidence with
either a left or right BGO. Page 3 of the attachment illustrates the 
fair symmetry in one of the old runs (4955). Page 4 illustrates the asymmetry 
in our most recent data.




3. Conference comments:

JDA - After talking to Jorde Jose and Christian Iliadis, 30P(p,g)31S on top 
of list as being most important reaction.

    - Both 25Al(p,g) and 26Al(p,g) also very important.

    - Some believe the key excitation energy in 22Mg is at 5711 rather than 5714.

    - Our resonance says the same. 

    - 15O(p,g)19Ne very important. Most likely the level
of interest is more important for x-ray bursts rather than nova. Question
now is where do we put it on our list?

4. Catania detectors:

AO  - Group at RIKEN plan to test some Catania detectors and would like
to work with us. Specifically with the use of TUDA.

    - We have 2 new detectors for testing.

    - Same problem with the buried anode causing a large dead layer exists.

5. 11C beam?

WL  - Is leaky 11C a problem, in the past WL has seen large variations in the 
supression of 11C.

    - Possible solution is the Catania DE-E detector for Z identification.

    - several DRAGON personel suggest our current IC may be more than adequate 
since we have already separated 13C from 14N at 650 Elab = keV/u quite nicely.

WL  - When would we get a beam?

JDA - earliest is 1 year, time is needed for beam development.

AO  - The ocassional video conference would be useful to keep 11C on the table.

6. 21Na:

UG  - Shows plot of the relative yield normalized to the beta-monitor. 
The two peaks CR saw with TUDA are seen in our data, it's unknown if the
difference in resonance energy is the same as that which CR found. See the 
second attachment first page for the yield.

    - Next two plots of the attachment are the gamma1-gamma0 plots of the two
different resonances. The lower energy resonance runs primarly through the 
ground state. UG and CJ are very happy with the data.  

7. Plans for the next 5 months:

JDA - The PGAC and associated electronics should get put back together for 
further comissioning studies.

    - The electronics cooling should be upgraded.

JP  - Want 2 separate data streams for the electronics. One for the gamma side
and one for the heavy ion side.

    - The long term plan involves a third data stream which could be used for other "stuff"
such as the germanium detector.

DH  - We need a coherent plan to propose.

8. Stable beam studies:

A list of possible stable beam reactions is given below:

JDA- 21Ne, we could retest the current results using the old tune.

CR - Could use a Si beam to get a charge state distribution, which would
provide useful info for the 26Al(p,g) reaction.

LB - 12C requires further analysis.

CV - 40Ca, can't do anything this fall but mabye something in the future.

JC - 22Ne(p,g) and 23Na(p,g) both could use further studies.

DH - 23Na(p,g) may have an associated acceptance problem with a large energy
gamma.     

    

end of minutes. :)