• Preparation for the restart of the LHC• 1st Run of LHC (2009)

• Problems encountered • Consolidation activities

• Commissioning• Status of the RP System/Services

• Production of DPs for the 147m Stations• Summary

TOTEM Roman Pots Detectors

G. Ruggiero (PH/TOT) TOTEM Collaboration Meeting10 March 2010

Activities during last quarter of 2009• Advance/Complete the commissioning of the Detector System

– Complete the connectivity in the USC (HV, R/O fibers...) – Run and control the system services with DCS

• Readout commissioning with DAQ– Control loop power-up and test (CCUM, DOH…)– FE hardware probing and programming– r/o tests with CalPulse Scans and Sensors ON

• First tests with LHC beam

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• Low Voltage Distribution• High Voltage Power UP

“Bad Surprises” found. Investigations and mitigations required access to the tunnel which, by that time, became very very rare.

Only a part of the RP System could run functionally and take data in the 2009 LHC Run

PROBLEMS SOLVED NOW!!!I will come back later on these...

Oct 09

Dec 09

1st run at the LHC in 2009

• First movement test of two pots with detector OFF the 29th of November.

• First movement of one Pot with data taking during a dedicated LHC run for TOTEM the 15th of December.– RP edge down to 4mm from the beam centre (~4.4σ). – LV1 trigger from the bunch crossing signals distributed by the

machine at IP5.

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During the LHC run all pots in garage position, away from the beam. Movement of the pots during LHC run only after agreement with the LHC Run coordination.

“Surprise 1”: Low Voltage distribution

Resulted in instability of:• the loop controlling the FE electronics • the data transmission

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Adopted solution: increase the number of channels of the LV with additional Power Supplies, to feed separately each DP with two channels (analogue and digital) and change cabling and connections accordingly.

In the tunnel the digital component of 3 Detector Packages is fed by a single channel of the power supplies Wiener Maraton, which are located in the tunnel alcoves. This would be adequate for the nominal consumption of the digital component seen in H8 but in fact…

Underestimated the effect of long cables (~100m) for the low voltage distribution of the RPs. During testing operations (extensive scans...) or resetting (GOH initialisation...), hitting the limits of the LV power supply.

top reference

surface

The POT in the Tunnel

Constrains in the POT

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Instead, to keep the parallelism between the top reference surface and the bottom of the pot, the bottom plate surface was milled reducing considerably the clearance sensor-thin window.

bottom plate surface

Pot Envelope

Reference frame

Sensor

The POT

By design 200µm of clearance between the sensors and the thin window.

“Surprise 2”: High Voltage Power UP

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Feet of reference

frame

Points of contact

HV shorting on the mass via the sensorImpossible to power up several sensors

several sensors in contact with the thin window in most of the pots.

Adopted Solution: replace the reference frames with new produced ones (feet 250µm longer) to regain the original clearance.

Reference frame

Consolidation works for this shut downSeveral actions on the RPs to take in the shut down period, planned carefully ahead of time.Continuous access to the tunnel required for few weeks

Activities completed by the 30th of January

Reference frames replacement• Extraction of all the 12 Detector Packages• Replacement of reference frames

new ones 250µm longer• Inspection and IV test of all the sensorsno damage found!• Revision of LV connectivity on the

Motherboards• Reinsertion/reconnection of the DPs

Low Voltage Distribution• Increase the number of LV channels to feed

separately each DP • Revision of cabling and connections accordingly

to the new LV distribution schemeVacuum System

• Improve the Vacuum system control adding one Pirani gauge on both sectors

• Calibration of the pressure sensors on the MBs in loco

Roman Pot Motors • Calibration of the movement of the RP Motors

with Laser tracker• Metrology of the BPMs adjacent to the RPs• Final test of the motors with the CCC

Status and Readiness: Services & DCS

• Vacuum System Operational – Link with DCS ongoing

• Cooling System Operational via DCS• Environmental/RADMON Sensors via DCS • LV System Operational via DCS• HV System Operational via DCS• DSS implemented, in test (DSS CMS team)

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After the consolidation activities a re-commissioning of the RP has started. Today the actual status is:

Status and Readiness: Readout&Trigger • FE control loop synchronizes

– All chips reachable and programmable• R/O data transmission Operational

– All GOHs synchronize with the ORX in the TOTFED• R/O tests with CalPulse Completed

– 99% of VFAT chips fully functional– Average channel noise ~800 el

• Trigger data transmission in test

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Running the RPs at this stage...

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• Start and initialization of the system reliably • Will be improved in DCS and DAQ at some point

(discussed yesterday).• The RP System can run safely if under surveillance

• A matrix of actions (on the detector control) to undertake during operation has been prepared.

• Waiting for the implementations of automated actions in DCS.

• …DSS should be operational from tomorrow

New DPs for the stations at 147m

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Production/assembly of hybrids (available at http://spreadsheets.google.com/pub?key=pzsoquTCfFRtXs_kHZq7FFg&gid=0 )

38 hybrids in production 3 PCB in stock

Recently, rather than the availability of components, we have missed the time to dedicate to the production of these DPs… The production of the DPs for the stations at 147m is continuing but at a low rate.

DP 13th has been assembled >>to be tested with beamDP 14th could be assembled by the end of March

Production/assembly of Motherboards and its components

New delivery of ~57+70 hybrids arriving the 23rd of April???

New DPs for the stations at 147m.Constrains...

• The availability of the electronics in very short time is mandatory if we want to complete the production of the RPs for this year.

• We must increase the time dedicated to the production. So far, all the efforts driven by activities in IP5.

• In the tunnel all has to be ready before the installation of new DPs– Still modifications for the cooling lines at 147m…

LHC planning foresees a technical stop of 3 days per month

New DPs for the stations at 147m.Planning...

• Same people doing more activities– Optimization by changing activities less frequently

• In H8 upgrading the system in order to test two DPs at the same time

• With the experience acquired with installations/commissioning last summer and this January, best would be installing a complete station per time rather then pot by pot…

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Summary

Roman Pots at 220mFirst data with one Pot in 2009

“Surprises” found but properly addressedHighly profited from the shut down period

Commissioning has advanced well

Roman Pots at 147mProduction ongoing but a change of speed is

needed

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