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[Zhenyu Ye <yezhenyu2003 AT gmail.com>]

2) Yellow alarms for the following modules 

These are temp alarms on the detector modules with daisy chained cooling tubes. 

Likely coolant is not flowing well through them (because of e.g. air bubbles) so the

reported temps (Inner 32, outer 28) are a few degree higher than normal (25)

What Ziyue did, which he referred to tricky operation on the cooling system, is the 

standard procedure of Refilling coolant to turn off chiller/pump, open the valve and 

then close it and turn on pump/chiller. This fixed disk 1 module 3, 5 but not disk 2 

8, 10 and 12 after 3 trials. He also tried to switch the pumps, which did not help.

To really fix this, one way, which we did before in the clean room, would be to turn 

off some cooling lines through the valves on the cooling manifolds on TPC surface, 

turn on the pump, and if the coolant starts to flow through this line, we reopen the 

closed cooling lines. Another way, which we have not tried before, is to increase 

the fan speed from 1100 RPM to 1500 RPM (see his email below)

Before fixing this, one could power these modules on and operate at higher temps, 

or keep them powered off.

3) HV trips

We can replace the HV module and see if it helps.

Zhenyu

On May 12, 2023, at 3:17 AM, Ziyue Zhang <zzhan70 AT uic.edu> wrote:

Hello all,

Yu's summary is very complete.

In short, and to answer Flemming's question, and a little supplement to Yu's summary:

1) PPBs are no longer overheated. This is fixed by connecting the tubes mentioned in part 1) of Yu's summary

2) Yellow alarms for the following modules:

    RDO1 disk1 module 3, 5
    RDO4 disk2 module 8, 10, 12

After some tricky operation on the cooling system, the alarms for RDO1 disk1 module 3, 5 went away, while those for RDO4 disk2 module 8, 10, 12 remained. Good new is by looking at the pedestal and noise plots, RDO4 disk2 module 8, 10, 12 are ok.

3) We have some unexpected tripped channels on MPOD03 (u2, u3, u4, u5). I tested them this evening, u4, u5 can be ramp up manually with very small ramp rate (10% of the original) and u2 u3 are just not stable with the original target voltage. u4 u5 can be fixed by further slowing down the ramp up procedure. u2 u3 will be investigated and discussed further tomorrow.

Best,

Ziyue

On Thu, May 11, 2023 at 4:55 PM videbaek <videbaek AT bnl.gov> wrote:

Hi Ziyue Zhang

Could you send a more detailled report to the FST list on the heating 
issue on FST and what you learned today.At the 10 o'clock meeting the 
conjecture was that one of the patch panels were overheating. Is this 
still true?
Whereas the shift entry today seems to point to a cooling loop issue on 
the disk 2

"We still get the yellow alarm on FST RDO 4, disk 2, module 8, 10, 12. 
We will stop this run and start a new run to test."

best regards
Flemming


-- 
Flemming Videbaek
senior scientist, emeritus
videbaek @ bnl.gov
Brookhaven National Lab
Physics Department
Bldg 510D
Upton, NY 11973

phone: 631-344-4106
cell     :  631-681-1596
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