7/27/2005

Alan presents diagram of proposed beamline.  He discusses the question of 
how to couple to beam dump.  It is suggested that the material for the 
supports of the beamline be G10 rather than aluminum or stainless steel.  
Todd suggests that an explosion test can be done using the proposed 
dimensions and discusses the production of the explosion chamber to be 
used during the experiment.

Bodo talks about the test run of the drift chambers.  The chambers 
responded well in the sense that the current drain was stable.  The 
highest luminosity used was a factor of ~8 lower than the experiment 
will use.  Luminosity scans were done as well as high voltage scans 
and the current drain scaled with both luminosity as well as applied 
voltage.  There exists a problem with the front end electrnics which 
limits data acquisition:  When the multi-hit TDC's record too many hits, 
the memory is filled resulting in an overflow error.  The result is that 
all 128 channels of the TDC no longer pass data to the DAQ.  It is 
difficult to pinpoint which channel causes the overflow, complicating 
the diagnostics of the problem.  However, Bodo suggests that data should 
be observed in the test lab in order to begin resolving the problem.  
This problem resulted in the loss of around half the TDC's at the highest 
rates during the test run.

Bogdan briefly discusses the direction of data analysis to use data taken
 with the lead-glass plus scintillator trigger to calculate rates per wire.
  He also mentions the apparent difference in effective efficiencies between 
pre-amplifier cards.  The observation is that the distribution of data among 
the wires is not uniform as expected (when using the double-scintillator 
trigger) but has "jumps" between sections of 16 channels.  The effect is 
not as dramatic at lower voltages (1400 V) and the cause is still not 
understood.  He suggests a special meeting between those involved to 
discuss this question perhaps near the middle of next week.

Albert presents progress on the neutron arm.  Last week, wiring of the 
cassettes was begun.  More than 60% of the cabling is connected to the 
detector, but not to the front end electronics.  Scaffolding is needed to 
complete this task.  Timing cables will be moved into the test lab within 
the week to begin their preparation.  Todd is able to offer the work of 2 
graduate students for a couple of days each to help with the cabling 
projects.  

Jacob has completed the connection of the signal cables both to the shower 
counter as well as the front end. High voltage and timing cables still need
 to be installed and extra manpower would be useful in this project.

Aidan plans to attempt polarizing a cell tomorrow.  It would be the first 
cell polarized in this holding field.  He has recently recieved the jig 
which mounts the cell and requires a GEn geometry cell, possibly to be 
provided by UVa.  The group from the UVa target lab plans to come here to 
install the optics in order to teach Ameya and Aidan.  Plans are made to
 install all existing optics while waiting for the last 6" mirror to 
arrive (~ 4 - 6 weeks.)  It may be possible to begin polarizing cells using 
an existing 4" mirror.  There is a discussion about the possible use of a 
"track" system using multiple small breadboards to mount the optics rather 
than purchasing and waiting for the delivery of a single large breadboard.

Vladimir has the news that a cell was cracked while being filled at UVa 
last week.  It may still be possible to use the cell as a water cell for
 water calibration.

Ameya will report next week on his progress in measuring the magnetic 
field direction using both a compass as well as a Hall probe.