We have observed the following problem with SM3 WFD Stopmaster, from
run 17430 till 17450:
- During runs 17430-17431 and 17444-17446, the ERP and CSPAM inputs of
the WFD Stopmaster for SM3 were apparently receiving the same signal,
since they show *exactly* the same number of hits and identical time-words.
At the same time, the CSPAM bit on SM3 and SM4 Stopmaster shows a
significant discrepancy (SM3 is present ~ 30% more than SM4 CSPAM).
As a reminder, runs 17432-17443 were PHRASE-only, due to the air
conditioning problems in Hall B that led us in turning OFF all the
rest of MACRO electronics.
- Starting with runs 17447, the above phenomenon ``decayed'' gradually,
in the sense that cross-talk between ERP and CSPAM decreased and
the SM3 and SM4 number of bits finally equalized.
- Please note that this behaviour coincides with the temperature in
Hall-B ! For as long as the temperature was high, the problem was
present, and as the temperature dropped, the problem went away.
We suspect some sort of crosstalk, either in the WFD Stopmaster module
or in the SPU module (=> this is the module that feeds the corresponding
signal to the Stopmaster) that created these fake bits.
All tests performed today in trying to address this problem resulted
negative, so - keeping a close eye on it for the near future - we called it
fixed.
A presto,
Ioannis & Nicola