Bi-Weekly Gen Meeting

Wednesday, October 27, 2004; 10:30 - 12:30

attendees: 
T.Averett, A.Gavalya,  
B.Reitz, A.Shahinyan
N.Thompson, B.Wojtsekhowski

1) meeting minutes: after Kathy has left, meeting minutes are 
   only posted infrequently. It was suggested, that the grad. students
   on site should write the minutes. BR will contact NT, AK and AK.

2) BW discusses several projects, to get input, if they 
   are still on track, if manpower is needed, etc.

a) target magnet - field direction measurement
   WK has constructed a device and done some testing, AG would 
   like to see the drawings. TA will contact WK. 
b) target magnet - power-supplies
   currently we use some borrowed ones, but need a final 
   solution. someone needs to look into the slow controls for 
   the PS. TA assigned Aidan to this task
c) target - beam steering / compensation magnet
   for the low beam energies beam staring from the target is not 
   negligible - we need someone to look into it, and eventually 
   work with ACC to design a compensation magnet
d) beamline:
   someone needs to work with ACC concerning the beamline: 
   windows, He-Bags, collimators etc.
   -> it was suggested that c) and d) would naturally be done by 
      the same person
e) cell studies: testing, evaluation and production
   no news from GC, BW will phone him. task will be shared between 
   W&M (TA) and UVA (GC)
   TA will produce a water cell for tests asap
f) Laser, Laser-PS, Fibers
   JP-Chen is taking the lead, Aidan is strongly involved
g) NMR
   TA (with Aidan) is working on it at W&M, Ameya at JLab. TA points out,
   that it is necessary, that two teams are working on it for now,
   since there is progress, but still too many  problems unsolved
h) EPR
   WK will start in Kentucky, TA is at the moment producing 
   test cells for him - it was suggested that Ameya should become 
   the grad.student expert on the EPR system
i) optical bench / optics
   GC and JP are probably the ones who can and should take the lead, 
   Ameya could maybe be the assigned grad student
j) target ladder:
   GC and AG are the leaders, Aidan is the grad student expert on this 
   item

3) AG has some questions about the target design
   concerning mounting of analyzer, neutral density filter, and 
   laser-beam dump. these items are discussed. 
   One conclusion was, that the material for the beam dump needs 
   to be tested (by one of the AK's - sorry I dont remember which of them)
   concerning a) temperature rise and b) depolarization of the target due 
   to the reflected light
   AG also shows some drawings:
   - two standard persons fit into the target magnet to work on the ladder
   - mount of RF coils
   - some details of the ladder design

4) TA reports, that concerning the NMR, they are still working on the
   water calibration - some progress but no breakthrough

5) BW reports on the status of the neutron arm
   - two modules with JLab bars will be fully assembled by the end of the week
   - all JLab type modules, all Glasgow type modules, and all modules for 
     veto detectors are on site. CMU type modules are expected to arrive 
     end of November
   - half moon shape of the detector was abandoned - the holes 
     in the modules were not exactly where needed. Latest simulations
     also show, that we only loose 5% (and not 20%) of the acceptance 
     with an rectangular arrangement. It is at present not clear,
     why earlier simulations indicated a larger effect
   - cage design is close to be finished.
   - the proposed arrangement of the lead is 2" in front of the vetos,
     1" between vetos and neutron bars, 1" behind the detector. 
     This lead will not be painted, but instead covered with 
     large plates. Additional lead can be placed in front of the 
     detector, but that lead needs to be painted.
     BR asks, if permanent front shield can be reduced during 
     experiment. BW explains, that we can only change the design to 
     a 1" lead shield, and add more (painted) lead if needed. 
     decision is postponed
   - BW want to have input for a design of a platform for the DAQ,
     so that all racks can be moved at once. Platform would be needed
     in April, so design should be finished mid January.
     AS and BR will provide input.
   - Dima Nikolenko repeated measurements of the time resolution 
     of the CMU bars, after fixing a bug in the electronics.
     He demonstrated that it is at least 250ps.
   - for the veto detectors 40 more PMTs are needed, since some 
     of the RCS ones were actually broken
   - We need 6 splitter boxes (NIM modules) for the Glasgow detectors 
     to be build from the JLab electronics group.

6) BR reports
   - nothing substantial new from the software development.
   - BW requests list of milestones, BR will work on it
   - students foreseen for software work (besides NT) are currently all 
     busy with either classes (AP, SR) and/or detector work 
     (SR, BC)
   - N20 setup is now equipped with DAQ system located in the Hall
     due to the delay in the DVCS running, it becomes more and more 
     questionable, if we get dedicated beamtime in November
   - in the N20 setup two NIM modules went bad - although they 
     run fine previously. Although it is only one out of 16 channels,
     due to the tight setup, it is quite often not possible to simply
     move that channel, but instead it is necessary to replace the 
     module. => we need on-site capability of quick repairs.
     BW will contact electronics group.


7) meeting adjourned