ATLAS week, CERN October 2001Philippe Grenier (CERN)

Cooling performances and testsduring the September 2001 calibration period

Fernando Varela / Philippe Grenier (CERN)

ATLAS week, CERN October 2001

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Cooling system in H8

water tank

output pipes

fridge unit

control box

return pipes

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Monitoring of the cooling system

cooling unit informations (ELMBs)

- input/output temp on each drawer- water output temp

- water flow

drawer informations (HV program)

- also, HV on the PMTs- 7 temp probes located in the drawers

Monitoring PVSSII application Database (web interface)

ATLAS week, CERN October 2001Philippe Grenier (CERN)

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Low voltages control

Drawer temperatures trends

PMTs HVs

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Stability of the systemnormal working conditions: T=18 oC, Flow=60 l/h

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Stability of the system during data taking

Tout<Mod2>=19.70.1 oC<Mod5>=19.60.1 oC

<Mod2>=18.30.1 oC<Mod5>=18.40.1 oC

<Cooling>=18.30.1 oC

Tin

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Increase of the water temperature in the drawers

(oC)(oC)

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Stability of the temperature inside drawer

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Cooling tests

1- variation of the water input temperature (16 oC 22 oC)

(180 GeV electrons shooting in cell A14)

PMT gain variation measured with particules

drawer temperatures variations

2- variation of the water flow (10 l/h 60 l/h)

drawer temperatures variations

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Water flow variationsCooling Temperature = 18 oC

optimal flow: 60 l/h

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Drawer temperatures variationsFlow = 60 l/h

6 oC3 oC

T(PMT) = 1/2 T(cooling)

ATLAS week, CERN October 2001Philippe Grenier (CERN)

PMT gain variation versus temperature

E/E = 0.2 % / oC(PMT) E/E = 0.1 % / oC(cooling)

resolution

total energy deposited versus temperature in PMT#22180 GeV electrons

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Conclusions

- optimal flow: 60 l/h (without LV in fingers)

- T(output - input) = 1.3 oC, for a flow of 60l/h

- Gain(PMT) = 0.2% / oC(PMT) = 0.1% / oC(cooling)

- cooling water temperature stability: 18.3 0.1 oC

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Still to be done

- Effect of room temperature variation with non-isolated pipes (using foreseen tubes)

- ( not yet operating: cooling unit for Cs calibration in blg 185 ready)

- Next year: re-optimize flow with finger LV power supplies

- Pilot Project (see next slide)

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Cooling pilot project in blg 185

- budget approved last week (50% financed by EP div JCOV committee)

- real size test (ATLAS): note

- Schedule (Sept 2001 - Sept 2002):- 15m high scaffolding available- components just ordered- start mounting/piping , until end of the year- tests to be done: Jan 02 Sept 02

ATLAS week, CERN October 2001Philippe Grenier (CERN)

Cooling pilot project in blg 185: Scaffolding installation