LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

LHC Vacuum commissioning

J.M. Jimenez

On behalf of AT-VAC

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Main Topics

• Breakdown of tests foreseen in preparation for beam

• Equipment folder e.g. tests results, handling of non-conformities, performance below specs, machine as commissioned vs. machine as specified

• Issues for sectorized cold check-out in parallel to HWC

• Alarms, signals and SW available in CCC

• Piquet and experts availability

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Description of LHC Vacuum SystemsIntroduction

• The LHC has 4 different Vacuum Systems belonging to two types of vacuum applications & technologies

Insulation Vacuum SystemsCryogenic line QRLMagnet Cryostats

The main purpose of the insulation vacuums is to decrease the heat exchange between the cryogenic lines/fluids and the external envelope at ambient temperature (RT).

Beam Vacuum SystemsCold Beam VacuumRT Beam Vacuum

The main purpose of the beam vacuums is to ensure the required the beam lifetime and luminosity while decreasing the beam/gas scattering and therefore the background to the experimental regions and the induced radiation to the surrounding equipmentsAs a general rule in the LHC, the two circulating beam vacuums are kept whenever possible completely independent. Exceptions can be found in the experimental regions and in the injection kickers in 5L2 and 5R8.

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Description of LHC Vacuum SystemsGeneral Layout of LSS

Attention…!

Vacuum crew uses :

Blue beam instead of Beam 1

and

Red beam instead of Beam 2

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Breakdown of tests foreseen in preparation for beam

• Vacuum instrumentation Each chain e.g. sensor – cable - patch panel or controller - PLC - PVSS monitoring

user interface is checked individually. Similar checks are made on the ion pumps. Pirani gauges are calibrated individually in situ

• Interlocks To cryogenic systems

Software interlocks given by two gauges: Pirani for the low level (0.1 mbar) and Piezo for the high level (500 mbar) – checked with cryogenics before cool down start

To other beam equipment RF cavities, kickers, diluters… hardware interlocks are checked with equipment owners before they start the

commissioning of their systems

Individual sector valve (see next slide) Sector valve chain interlock to the BIC

The sector valve chain is checked using simulators instead of the valves (can not be opened right now) and a BIC controller provided by AB/CO

In presence of a pressure interlock, the valves will only be closed when the beam dump signal is confirmed by the BIC interface

The action buttons for the sector valves in the PVSS monitoring user interface are inhibited in presence of beams Do we extend that to VPIs and VGs?

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Breakdown of tests foreseen in preparation for beam

In the LHC, the cold beam vacuum sectors are always surrounded by RT beam vacuum sectors. But the RT beam vacuum sectors can have cold or RT beam vacuum sectors at their interfaces. Sector Valve Closing

A vacuum interlock generated by the ion pumps and Penning gauges located upstream and downstream of the sector valve (x) will fire the beam dump and then the sector valves (x), (x-1) and (x+1) will be closed. As a general rule, 3 or 4 signals are used to interlock the valve closure and the interlock will be triggered when n-1 signals are positive.

Sector Valve OpeningThe opening of a sector valve isolating a Cold / RT beam vacuum is

allowed only if:• The magnet is at his nominal temperature and the Penning of the Cold

beam vacuum sector indicate pressures below 10-7 mbar• The Penning gauge of the RT beam vacuum indicate pressures below

10-7 mbar and VPIs are all OKFor an interface between two RT beam vacuums, the Penning

gauges of both sectors shall indicate a pressure below 10-7 mbar and VPIs are all OK

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Breakdown of tests foreseen in preparation for beam

Combined beamsMKIs

Case 1 Case 3Case 2

Beam Vacuum Sector Valves Closure

Green : Valve can be openedRed : An interlock is detected

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Equipment folder

• Instrumentation Tests results

Reported in paper travelers Non-conformities

Repaired as soon as detected Performance below specs

Nothing identified yetUpgrade of the PVSS interface and PLCs software are made 4/5 times

per year to adapt for new user requirements based on operation experience

Machine as commissioned vs. machine as specifiedNothing identified yet

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Equipment folder

• Vacuum chambers and components Test results (vacuum acceptance tests)

Chambers have been validated during the NEG deposition process – Tests and traceability reports are stored in MTF

Warm interconnecting modules, BPMs, sector valve modules and gauges have been validated in bld113 test benches – Tests and traceability reports are stored in Nice

LHC equipment manufactured by AB Department (except BPMs) have been validated in bld867 test benches - Tests and traceability reports are stored in Nice

Non-conformities during installation Non-conformities during vacuum acceptance tests are reported in the travelers stored in

Nice Non-conformities during installation in the tunnel are reported in EDMS. Each non-

conformance generates a non-conformity report which states the actions and induced limitations

Performance below specs Reporting depends on the stage at which they were detected e.g. test results or installation

Machine as commissioned vs. machine as specified See the template of the non-conformity reports

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Equipment folder

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Issues for sectorized cold check-out in parallel to HWC

• Instrumentation is checked prior to: Starting the cool down: checking of the instrumentation of the arc magnets

insulation vacuum and standalone magnet insulation vacuum Starting of the bake out on the RT sectors: instrumentation on beam

vacuum These checks shall be completed in parallel with HWC

• Validation of valves Final checking can only be made when the magnets are at cryogenic

temperature These activities will be made in parallel with HWC activities

• Tests during cold check out Sector valves and sector valve chain shall be retested during cold check out

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Alarms/signals/SW available in CCC

• Signals Status of vacuum sectors, instrumentation, pumps… can be accessed using

the PVSS software interface (see next slide) This interface is installed in the CCC in the LHC and TI platforms and in

cryogenic control rooms. Shortly, the vacuum pressure for the cryogenic sector will become available in the Control Middle Ware (CMW) for cryogenic crews

Vacuum OK signal for cryogenics is available in GTPM

• Alarms and signals Alarms are not handled yet, discussion are on going with AB/CO and AB/OP

to define which type of alarms shall be generated and how their shall be handle and “compressed”

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Description of LHC Vacuum SystemsVacuum Supervision Interface

QRL Insulation Vacuum

Magnets Insulation Vacuum

BLUE Beam or Beam 1 Beam Vacuum Sector Valve Chain*

RED Beam or Beam 2 Beam Vacuum Sector Valve Chain*

* Red = Valve(s) closed Green = all valves opened Blue = Control Problem or undefined positionInterlock level on insulation vacuum

Vac cryo OK 0.1 mbar alarm 500 mbar alarm

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Description of LHC Vacuum SystemsVacuum Supervision Interface

Beam vacuum

TD68 dump vacuum

TD62 dump vacuum

Sector valve synoptic

Detailed synoptic

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Description of LHC Vacuum SystemsVacuum Supervision Interface

QRL VacuumInstrumentation

Magnet VacuumInstrumentation

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Organization and duties of the Vacuum Piquet Support

The operation of the vacuum systems of the running accelerators will rely on:

• A stand-by Piquet Service of 2 persons (rules for stand-by applies e.g. administrative circular N°27) Stand-by starts on Wednesday at 9h and ends next Wednesdays at 9h (within the

limit of 12 h/day and 57 h/week) After being called by the CCC, the Piquet team has to identify the cause of the

interlock and try to fix it. The duties of this first line is limited to the instrumentation, ion pumps and sector valve problems. Access to underground areas may be required

Other problems like controls failure and leaks… shall be addressed after taking advise with the experts. The experts shall be called by the vacuum Piquet via the CCC in order to register the intervention in the CCC logbook

• Vacuum experts (best effort, not in stand-by) List of volunteers which are or not member of the stand-by service The list of experts will only be communicated to the stand-by piquet The expert volunteers will provide assistance to the stand-by piquet on a best effort

basis. They will be called via the CCC in order to register the intervention in the logbook. The administrative circular N°27 applies for the overtimes and interventions

The expert, if available, could help to solve the problem by phone or could decide to intervene together with the stand-by piquet service

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Organization and duties of the Vacuum Piquet Support

• Why using this new organization of Vacuum support for the running accelerators? Stand-by piquet service will be able to solve about 90% of the problems

Gauge is off and generates an interlock to the cryogenics or to sector valves

Gauge controller is failing restart or exchangeSector valve is blocked or is giving an undefined position launch an

open or close command, check the valve controller and reset it if required, increase the pressure using the pressure reducer

Experts (volunteers on best effort) helping the Stand-by piquet teamExperts will provide an assistance to the Stand-by team and therefore

will avoid stresses during the interventionsIntervention on the LHC insulation vacuum e.g. exchange of a faulty

turbo or installation of additional pumpingLeak detection using Argon or using a leak detector varnishingLeak repair when a venting of the sector is requiredPLC related problems (by pass of the interlocks could be required)

LTC Extended days, 03 March’08 J.M. Jimenez, AT Vacuum Group

Organization and duties of the Vacuum Piquet Support