Minutes Dragon Meeting    26 August 03 

Present:   DH JDA DO(recorder) PM JR CJ ZL ML CR CG MA AL AB MH AM AO MP 
 
Facility Reports: 
 
     HS and HB are still working on clearance problems between the solid target mechanism
and the west BGO's.  Seems to be in hand. DG  to reassemble the BGO's. 
 
     ML did a  late night test of the gas target with both up and downstream pumping tubes removed. With the gas pressure at 6 T in the target, the D4 downstream pressure was 4E-5
or about 30 times normal.  It was not clear where the problems were, power levels in the 
turbo pumps were not recorded.  It was not necessary to have the upstream pumping tubes 
removed. 
 
To do:   Put gas tgt in,  1. repeat no dnstrm pumping tubes 
                                     2. standard pumping tubes 
                                     3.stubby pumping tubes 
             Solid tgt in     test pumping and with beam. 
Do we have enough info to justify ordering anothe turbo? 
 
Test of MCP  (ML) 
   Results of tests of the MCP were presented.  The double peaking in the timing spectrum 
was identified as alternate strips in the strip detector giving different times. Solution 
was to use 1 strip only. 
 
   RF time  no foil   1.9 ns fwhm 
               foil in       6.7 ns fwhm  due to straggling in foil? 
 Nonuniformity of thichness? 
plans :   use thinner foil  to reduce energy loss  but maybe increase non uniformity. 
 
The bias voltage on the MCP  has been increased from 3020 to 3240 due to a new cable. 
The position signals from the resistive anodes behind the MCP are not symmetric. 
Corners A and D recieve most of the signal, noise peaks dominate on quadrants B and C. 
 
GIOS stuff   (JR) 
Work continues to increase the solid angle acceptance above 20 mr. 
Resonance  of 12C + alpha of 9.84 MeV has been chosen which gives 50 times the rate.  Some
concern expressed about the accuracy of the GIOS file, as to drift lengths etc. 
There are 16 squeeze points where there are geometry constaints. 
Quadrupoles were varied but no sextupoles were used.  A reasonable solution achieved, with
the envelope filling the pipe at Q8 and becoming too large at Q10. 
 
The work assumes the same quadrupoles and geometry used, so no money required for hardware.  However, more pumping power at the gas tgt is needed. 
 
"What I did this summer" (CG )  12C (alpha, gamma) 
   Can we distinguish decay paths by gamma analysis?  An attempt was made to identify which
decay path was used by creating response functions for each gamma and each detector.  MP 
suggested that the analysis could benefit from a low statistics modification to Gaussian 
distributions that he has found.  This has been added to Physica by Joe Chuma. 
CG's final opinion is that we are not able yet to distinguish decay paths.  Final report 
submitted. 
 
Where losses occur along the separator  (MA) 
    His study found that most losses of recoils accur in ED2 and in the final beam pipe. 
The obvious solution is to open the slits to a wider opening.  The energy assymetry can 
be eliminated by tuning the separator lower by 0.5 percent  Final report submitted.