[Halld-tracking-hw] Tracking Meeting minutes posted

[Naomi Jarvis]

Online at https://halldweb1.jlab.org/wiki/index.php/April_10,_2013_Tracking_CDC/FDC#Minutes

and below without the picture.


Regards,

Naomi.



Present: Curtis, Naomi, Beni, Simon, Lubomir, Mark

FDC Update
The HV problem on one HV sector in package #3 was fixed. It was caused by a sense wire tail sticking out of the solder. The cell was installed back in the package and will be tested soon.
The set-ups to test the cooling system are almost ready. One set-up will be used to test for leakages (at 100psi) in the manifolds installed on one of the packages. The other will test the temperatures and flows in one loop using the Fluorinert chiller.
The package #2 that was already tested at JLab was moved back to Blue Crab. Beni: at lower flow rate (100ccpm instead of the nominal 250ccpm) some of the channels trip once per day, not clear why.
According to Fernando there are 20 fADC125 that can be used after Cody finishes the tests. Three will be shipped immediately to CMU as soon as we have them (Beni). There are problems with the quality of the boards which can delay the production by more than a month.
CDC Update
Naomi has started taking cosmics data with the CDC, looking at 3 boards at a time, with the aim of finding a signal on each straw. Gas mix is 50/50 at 1100sccm and most of the boards went to 2100V, with very little current drawn (few nA for 3 boards). Usually they start off at 10-20nA total and decrease to below 5nA. So far just one of the boards tripped (at 80nA) and will be revisited. The picture shows signals from mixed events in board B1 (straws in innermost stereo rows E,F,G).
There was one bizarre incident where the pedestals on first one and then all 3 boards dropped, and the ECL/PECL converter output pin voltage went to zero, so the flash was not triggering correctly. This pedestal drop was never seen with the prototype. Usually the pedestal rises when the LV supplied to the HVB decreases.
Pedestal width is 15-20 ADC units (mean is 16); channels without a straw have pedestal width 14-15 (4096 full scale ~ 0.5V).
2 channels in the fadc are not functioning perfectly (one has low gain and huge offset, another does not have continuous range of output values) but are usable.

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