DT Hardware Status and Monitoring

A. Benvenuti INFN BolognaMuon Barrel Workshop 28/09/2010

A few items:• High Voltage• Low Voltage (connectors)• Gas Analysis• VDCs• Monitoring/Alarms• UX Maintenance Plans (Long Term) • Out of ISR

HV Problems Summary

No New Problems since the end of February but, old YB+1 MB3 S07 came back The last “real” HV trip (YB+1 MB2S08 SL1) occurred on July 19 during the Magnet ramp down

Problems Turning HV ON from OFF StateDuring HV ON with warm ramp on 31/08 the following layers tripped:1) YB+1 MB4S04 SL1 L2 w1 2) YB0 MB4 S10L SL1 L2 w1 3) YB-1 MB4 S10 SL3 L4 w1 4) YB-1 MB3 S03 SL3 L3 w1 5) YB+2 MB3 S11 SL2 L2 w0Chambers 1 to 4 had exactly the same problem:At the first step (1200/1000/800) w1 was discharging without any current spikes in strips or cathodes. In some cases, HV spikes are seen for w1.The program attempts to bring the layers back to STANDBY values (1900/1800/1200). Note that no current spikes are seen in w1 once the STANDBY values are reached. The spikes seem to be due to a regulation problem in the A877.

Similar behavior was seen in the past for:YB+1 MB4S04 SL1 L2 w1 on 26/02, 05/03 and 08/04YB-1 MB4 S10 SL3 L4 w1 on 22/01YB-1 MB3 S03 SL3 L3 w1 on 05/03

YB-1 MB4S10

Problems Turning HV ON from OFF StateYB+2 MB3 S11 SL2 L2 got stuck with w0 in Over Current at the first step (1200/1000/800) with w0 current spikes withoutany spikes in strips or cathodes. The layer went up to nominal values without problems by lowering w0 to 900V and bringing w1, strips and cathodes to 2000/1800/1200. After that, no current spikes were seen in w0.

Apparently, this channel does not regulate properly when the strips and wires are at “low” values.

This problem was already seen on 05/03 and is reproducible (done before exchanging the A877) But it cannot be reproduced in B904 (Marina) Wait to replace the other modules until the T.stop Borsato and Marina to setup a meeting with CAEN

YB+2 MB3 S11 SL2

A876 Problems: • wire-Strip discharges in all layers and SL in YB0 MB2 S06 and YB+1 MB3S10 Not reproduced in B904

• Cathodes discharges in all layers and SL in YB+2 MB3S09 and in YB+2 MB3S04 (both 12-15 July)

A877 Problems: • Apart for the new problem during HV ON from OFF a few modules had regulation problems• In total 3 A877 were replaced since the June CMS week In addition one A877, fresh from repair, was used in UX but it had another “feature”

YB+2 MB3S04YB+1 MB3S10

A3100 Power DistributionMeasurements of the current distribution from the A3100 to the SC crates done in July showed large anomalies for YB0 Top and to a less extent for YB+1 Bottom.During the Technical stop at the end of August, Cristina identified the source of the problem in the Powerclaw connectors at the TIMBUS in the SC crates backplane.

The Cure (Cristina, Davide, Ignacio)

• all PP75 connectors inside the crates were re-crimped following the same procedures as done in January and strain relieved.• the contacts were cleaned and the powerclaw rotated 180° to improve the contact surface• lubricant was applied to the surfaces to minimize fretting The power distribution is now quite uniform across all SC crates as a test, the lubricant was also applied to all powerclaw connectors in YB0

A3009 MC Vcc Connection ProblemSpotted by Ignacio:

Checked during UX access yesterday:• Temperature = 36.7 °C• Crimps OK (impossible to crimp with B ON)• lot of dust around the connectors• Vcon normal after re-inserting connectors and blocking with cable tie wedge yet another flakey contact

Vcon Saga

“Official” list of known and “under watch” cases

Found at 42°C, Nothing unusualOK after usual plug-unplug fix

MC switched OFF due to VconOccurred twice, second time after lubricant

• YB0 is unusually prone to Vcon problems• Replacement of A3100 Power claw connectors with lugs has been postponed:

No problems observedUgly solution (only one Output)

Not yet at the end of the story

All Wheels 12324 11911

Gas System Good Performance, essentially no downtime• Some improvements on gas analysis system• Still some vagaries to be followed up Loss of ~ 1120 liters/hour (should be ~400) Flow equalization Gas Purity (CO2)

Online gas chromatograph to be operational before the end of the year• From our side: Progress on PADC monitoring/upkeep (Daniel T.) Decision on DT operation at Absolute Pressure

YB-1

Good stability since May, apart for a problem with calibrations in July/August (not shown) Plots identify chambers with higher O2 contamination, not necessarily in the chambers Overall O2 increase on 20/09 attributed to a CO2 change, higher purity to be used in the future (RG) Overall O2 increase for YB-2 on 06/09 due to a bad cell calibration Similar results for the other wheels

YB+1

• Good stability of O2 content • The 20ppm increase in 20/09 is attributed to the CO2 delivery• Note the O2 increase in YB-2 due to a problem with the analysis cell

YB-1

• Large spread in YB-2• Analysis cells were recalibrated by the manufacturer in August• Later measurements are more uniform • YB+1 has a lower H2O content than remaining YB

YB+1

As a summary: Some progress in the Gas Analysis racks performance We have a list of the chambers with largest O2 contents It would be interesting to check the drift velocity for YB0 MB1S02 from the data Real progress only after the integration of the online gas chromatograph

and corresponding H2O content

VDC (in a nutshell)

A troubled life

Reference Mixture

Common Supply

But some hope for the future

Thanks to Daniel and Lars for tending several VDCs through HV problems, supply failures, PC changes……..• Taken at face value, there is ~2.5% difference in the Supply/reference Vdrift• N2 contamination in supply line should be checked with gas chromatograph (done/ongoing)• At present N2 level is not monitored, stabilized by fresh mix in supply line

For the first time, we have a delivery date for the VDC system (thanks Hans):

January 15 2011• Lot of work still to be done:

DCS systemUG infrastructures…..

Unified Temperature Alarms, Displays (and more) Luca Ciano has set alarms thresholds on the extensive collection of thermal sensors that Franco installed on:

- Thermal screens- MC Cooling manifolds- Sector 4 and 10 chambers (HV and Front-end side)- Sector Collector crates- LV Sector Collector cables

• Alarms (sms + e-mails) are sent to the usual suspects when temperature exceeds threshold by 1, 2 and 3°C

Note: Menu at right hand corner visible ONLY when touched with the mouse

Time histories are available from “Temps” (inline) and “Plotgen” (background)

Page :1) Thermal screens and LV cables2) MC Cooling manifolds3) Sector Collector crates and S04

S10 chambers HV side4) Sector 4 and 10 chambers Front-

end side

plus other functionalities requested by additional customers…..

and a multitude of options in http://vmepcs2g16-14/production/errlog/

New DCS FeaturesAdded by Marina G.

Percentage of Active Detector

Sector Collectorand

DTTF, DDUCrates Monitoring

Martin GastalTIG Meting

Medium and Long Term Planning

We were asked to provide a list of the maintenance activities for the foreseeable future

I provided Martin with the list of known DT problems

Anton has given the list for the RPC

A Snapshot of DT and RPC (Barrel) Maintenance Work (as of today)

Thanks to Cristina and Gianni for providing the list for the MC maintenance.• Only work requiring access to the detector is entered in the table • Only RPC maintenance that requires moving the chambers is included • Mistakes are possible but this is not the last version

The Present Plan as Enshrined in TCM, TIG and TECOPA Meetings

• It is 25m x 18m (wall to wall) for the Muon Community• we asked for 15m x 12m (but space is needed to move the chambers ) Recommended reading: “ The new tenant” a play by Eugene Ionesco

As usual, I did not date this but it goes back to January 2008

That’s all folks ….