Operators: ajmasch zwart kdow
I find the situation here a little confused. AJM has been doing beam position versus empty cell running since TB reports that unpol gas feed is disconnected from the cell.
We spoke with Ernie who confirms that he will open the hall and check the connection first thing in the AM. Then running will procced (see MF E-mail) to measure detector performance with a full target.This will include vertex reconstruction. Of course we would like to see the clean triangular distribution from the target with a single "rabbit ear" from the collimator upstream.
Continuing the beam postion/aperture studies, we took one run (2955) with the beam offset in the collimator both horizontally and vertically (+1.5 mm horiz, +1 vert mm) . The lifetime of 4-6 minutes was quite poor under these conditions as could be expected.
As a previous e-log indicates there may still be some question as to the status of the gas connection. We took one run with 0.1 sccm of deuterium to see if vertex can be resolved. This was done with the beam centered in the collimator. The beam conditions were very good. (20 minute lifetimes all BQM ~< 100) No obvious vertex was observed in on-line gui.
For reference: under these conditions 60 mA beam, 20 min. lifetime. Physics trigger rates were: Phys0 466, Phys1, 325, Phys2 253, Phys3 4, Phys4 30, Phys5 42K, Phys6 32K.
EKE is opening hall for Mechanics at 7AM.
Adam. Maybe HV gui should make explicit reference to Ohio Neutron Bars. It is not apparent where they are from the high level screen.
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