Detector Decommissioning Related Activities at DØ

George GintherFermilab and University of Rochester 2 March 2012

Recent Activities• Began nitrogen purge of VLPC cryostats on 23

January• Collision hall radiation survey completed on 24

January– Was previously posted as a radiation area– Now posted as a radioactive materials area

• Nitrogen Dewar 39 empty as of 26 January• Suspended LN2 delivery to dewar 42 as of 1

February• Powered down calorimeter test stand as of 9

February• Pond water pressure loss on 10 February• Requested variance for DAQ nodes to support

monitoring of SMT annealing• Transition nodes to SLF5 (and Clued0) and shutdown

of other nodes in progress• Refrigerant recovered from Trane chiller• York chiller seals being repaired

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• Tours– During Collaboration meeting– For EDIT school

• Re-using various components– 120 farm nodes moved to Clued0– Helium purifier disconnected for NML CMTF– LN2 recapture system targeted for LAr35– Portable dehumidifiers to SiDet– Preparing HV crate for MINERvA veto– Dryers and compressors for NOvA near detector

APD purge– Relays, cables

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Solenoid

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VLPC cryostats cold block temperatures

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Purging the VLPC cryostats(Analysis and plot by Russ Rucinski)

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Liquid Helium Inventory

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Liquid Nitrogen Dewar 39

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Argon Storage Dewar

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Liquid Nitrogen Dewar 42

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Current Status• Helium inventory in gas storage tank• Solenoid coil currently at 266K and warming• Calorimeters warming up (and will be for many

months)• Evaluating potential re-use of argon inventory

– Suspended delivery of liquid nitrogen– Wipe at transfer line filter

• VLPC cryostat purge continues– AFE readout still powered

• SMT chiller at 16C– SMT readout in standby awaiting additional annealing

measurements• DAQ running unrecorded zero bias in auto-pilot until

next SMT annealing measurement11

As conditions (and resources) permit

• Continue powering down rack infrastructure• Continue preparations of online computing cluster

for transition to offline cluster– Identify, backup and archive critical information

• Continue high bay preparations• Continue harvesting components for re-use• Continue preparations for basic exhibit• Shut down silicon chiller and purge system• Drain Deionized Chilled Water detector systems and

purge• Secure halon fire suppression systems

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Clean Out and Harvest• The mechanical crew is well into the process of

preparing the DØ Assembly Building high bay to accommodate MicroBooNE TPC assembly

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LAr 1

• 1 kiloton liquid argon membrane cryostat

• About 16 times as much argon as used in DØ calorimeter cryostats

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