At 100 mA, 2.0 SCCM the start counter at 1675 V at 20 mV thresholds
(both sides) sees about 40 KHz (coinc). we should not go above that
At same time at forward angles, paddles 0-3 measured 300-350 Hz, 100 Hz,
and the last two 50 Hz. The trigger rate at the top of the fill was 9-13 Hz
recalling the converstation with Chi, in a backward angle setting (4-7)
the trigger was only 1/4-1/3 of the above, paddle 0 was at abut 100 Hz,
the last two paddles about 20 Hz. Of course the start counter rate does
not change,
If paddle 1 keeps in not behaving, then please put it at the most backward
angle (behind R7) in the next setting. If you are more comfortable, put
all paddles at 20 mV thresholds (top/bot). Note tha the combinatorials of
40 KHz and 100 Hz in a 20 ns window are small (0.1 Hz) but not entirely
negligible at the most backward angles.
Can we run with the start counter at 30 mV and get the same trigger rate ?
By now we know that the tape work around the paddles is not very good.
Just be aware of that if you get an anomalous low result: I guess on the
right sector you can peep through with blastcam, else check in the hall
I am always reacheable by phone, except between 9 and 11 pm tonight.
regards,
-- t
________________________________________________________________________________
Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
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