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The LHC Collimation system is a system designed to provide beam cleaning and limited passive protection to the LHC. The precise control of the jaw positions versus time and beam position has important relevance for machine protection of the LHC. The system is protected by various interlocks against wrong positioning. These interlocks are subject to thourough testing as part of MP procedures.

The results of machine protection (MP) tests for the LHC collimation system are documented in EDMS reports and in the MTF database system (also used for production and quality control of collimators). Here we provide easy links to the relevant documents for all installed collimators, which are treated through the LHC collimation project.

Quick jump to:

Test Position/Gap interlocks vs Time, Energy and Beta-star Test local mode interlock
Test power cut and PRS reboot interlock Test temperature interlock
Test RBAC interlock Test MC-Collimation role

General testing history:

A document describing the specific machine protection tests can be found in:
https://edms.cern.ch/doc ument/889345/

And the link to the LHC Machine Protection can be found at Machine Protection Web Page

2017 Replacement of TCP.C6L7.B1 with BPMs. Installation of TCSPM.D4R7.B2 (ver). Replacement of TCTPH.4R5.B2 and TCL.4L5.B2 with collimator with WIRE and BPM.
2015 Replacement of TCT collimators with collimators with BPMs (TCTPs). Addition of TCL.6 collimatos.
March 2012 Installation of 2 new collimators at IP2: TCTVA.4L2.B1 and TCTVA.4R2.B2 replacing TCTVB.4L2 and TCTVB.4R2. System further checked by random tests in various IR's. New watchdog in IP1/5, all collimators were tested in these IR's.
2011 Recheck ALL collimators following a major software upgrade. (1) Adding beta-star limits, (2) new logic to stop motor in Injection Protection.
February 2010 Interlocks for 1 modified collimator and the TCDIV.29012 (replacing TCDIH.29012) fully tested and verified. System further checked by random tests in various IR's.
October 2009 All interlocks tested and verified.

Test Position/Gap Interlocks vs Time, Energy and Beta-star

The collimator position interlocking is based on the comparison between the measured jaw positions and collimator gap values against user-defined limit thresholds that can be expressed as a constant (discrete) value, as time-, energy- and beta-start- dependent functions. If the measured values exceed the interlock thresholds, the collimator survey unit (PRS=Position Readout Survillance) removes the beam permit.

Each LHC collimator has 6 LVDT (Linear Variable Differential Transformer) sensors for direct jaw position and gap measurements. Each of them can trigger a beam interlock if the measured readout exceed INNER or OUTER limit values. In total, there are therefore 12 interlocks per collimator that have to be tested in order to validate the machine protection functionality of the PRS unit. In addition, there are energy-dependent and beta-star-dependent limit functions (one OUTER limit for each of the gap LDVT for the energy limits and one OUTER and one INNER limit for each of the gap LDVT for the beta-star limits, i.e. six additional interlocks per collimator (2 for the energy-dependent and 4 for the beta-star-dependent). An example of the offline analysis test is given in figure bellow.

Test of Position and Gap Interlock

Summary: Test Position/Gap Interlocks

  Year     Result  
2017 Tested LHC COLL e-log: 26 april 2017

  

    Machine Protection:
Position/Gap Interlocks vs Time, Energy and Beta-star    
 Collimator Slot  MTF EMDS Doc.
latest
EDMS Doc.
older
TCDD.4L2 MTF 2010
TCDIH.29012 2009
TCDIH.29050 MTF 2012 2011, 2009
TCDIH.29205 MTF 2012 2011, 2009
TCDIH.29465 MTF 2012 2011, 2009
TCDIH.87441 MTF 2012 2011, 2009
TCDIH.87904 MTF 2012 2011, 2009
TCDIH.88121 MTF 2012 2011 2009
TCDIV.20607 MTF 2012 2011, 2010
TCDIV.29012 MTF 2012 2011, 2009
TCDIV.29234 MTF 2012 2011, 2009
TCDIV.29509 MTF 2012 2011, 2009
TCDIV.87645 MTF 2012 2011, 2009
TCDIV.87804 MTF 2012 2011, 2009
TCDIV.88123 MTF 2012 2011, 2009
TCL.5L1.B2 MTF 2012 2011, 2009
TCL.5L5.B2 MTF 2012 2011, 2010, 2009
TCL.5R1.B1 MTF 2012 2011, 2009
TCL.5R5.B1 MTF 2012 2011, 2009
TCLA.6L3.B2 MTF 2011 2010, 2009
TCLA.6R3.B1 MTF 2012 2011, 2010, 2009
TCLA.7L3.B2 MTF 2011 2009
TCLA.7R3.B1 MTF 2011 2009
TCLA.A5L3.B2 MTF 2011 2009
TCLA.A5R3.B1 MTF 2011 2009
TCLA.A6L7.B2 MTF 2011 2010, 2009
TCLA.A6R7.B1 MTF 2011 2009
TCLA.A7L7.B2 MTF 2011 2009
TCLA.A7R7.B1 MTF 2011 2009
TCLA.B5L3.B2 MTF 2011 2009
TCLA.B5R3.B1 MTF 2011 2009
TCLA.B6L7.B2 MTF 2012 2011, 2009
TCLA.B6R7.B1 MTF 2012 2011, 2009
TCLA.C6L7.B2 MTF 2011 2009
TCLA.C6R7.B1 MTF 2011 2009
TCLA.D6L7.B2 MTF 2011 2009
TCLA.D6R7.B1 MTF 2011 2009
TCLIA.4L8 MTF 2012 2011, 2009
TCLIA.4R2 MTF 2012 2011, 2009
TCLIB.6L8.B2 MTF 2012 2011, 2009
TCLIB.6R2.B1 MTF 2012 2011, 2009
TCP.6L3.B1 MTF 2012 2011, 2009
TCP.6R3.B2 MTF 2012 2011, 2009
TCP.B6L7.B1 MTF 2012 2011, 2010, 2009
TCP.B6R7.B2 MTF 2012 2011, 2009
TCP.C6L7.B1 MTF 2012 2011, 2009
TCP.C6R7.B2 MTF 2011 2010, 2009
TCP.D6L7.B1 MTF 2011 2009
TCP.D6R7.B2 MTF 2011 2009
TCSG.4L3.B2 MTF 2011 2009
TCSG.4L6.B2 MTF 2012 2011, 2010, 2009
TCSG.4R3.B1 MTF 2011 2009
TCSG.4R6.B1 MTF 2012 2011, 2009
TCSG.5L3.B1 MTF 2011 2009
TCSG.5R3.B2 MTF 2011 2009
TCSG.6L7.B2 MTF 2011 2009
TCSG.6R7.B1 MTF 2011 2009
TCSG.A4L7.B1 MTF 2011 2009
TCSG.A4L7.B2 MTF 2011 2009
TCSG.A4R7.B1 MTF 2011 2009
TCSG.A4R7.B2 MTF 2011 2009
TCSG.A5L3.B2 MTF 2012 2011, 2009
TCSG.A5L7.B1 MTF 2012 2011, 2009
TCSG.A5R3.B1 MTF 2011 2009
TCSG.A5R7.B2 MTF 2011 2009
TCSG.A6L7.B1 MTF 2011 2009
TCSG.A6R7.B2 MTF 2011 2009
TCSG.B4L7.B1 MTF 2011 2009
TCSG.B4R7.B2 MTF 2011 2009
TCSG.B5L3.B2 MTF 2012 2011, 2009
TCSG.B5L7.B1 MTF 2011 2009
TCSG.B5L7.B2 MTF 2011 2009
TCSG.B5R3.B1 MTF 2011 2009
TCSG.B5R7.B1 MTF 2011 2009
TCSG.B5R7.B2 MTF 2011 2009
TCSG.D4L7.B1 MTF 2011 2009
TCSG.D4R7.B2 MTF 2011 2009
TCSG.D5L7.B2 MTF 2011 2009
TCSG.D5R7.B1 MTF 2011 2010, 2009
TCSG.E5L7.B2 MTF 2011 2009
TCSG.E5R7.B1 MTF 2011 2009
TCTH.4L1.B1 MTF 2012 2011, 2009
TCTH.4L2.B1 MTF 2012 2011, 2009
TCTH.4L5.B1 MTF 2012 2011, 2009
TCTH.4L8.B1 MTF 2012 2011, 2009
TCTH.4R1.B2 MTF 2012 2011, 2010, 2009
TCTH.4R2.B2 MTF 2012 2011, 2010, 2009
TCTH.4R5.B2 MTF 2012 2011, 2009
TCTH.4R8.B2 MTF 2012 2011, 2010, 2009
TCTVA.4L1.B1 MTF 2012 2011, 2009
TCTVA.4L5.B1 MTF 2012 2011, 2009
TCTVA.4R1.B2 MTF 2012 2011, 2009
TCTVA.4R5.B2 MTF 2012 2011, 2009
TCTVB.4L2 MTF 2009
TCTVB.4L8 MTF 2012 2010, 2009
TCTVB.4R2 MTF 2011 2010, 2009
TCTVB.4R8 MTF 2012 2011, 2009
TDI.4L2 2012 2009
TDI.4R8 2012 2009

Test Local Mode Interlock

The test consists on chequing the interlocks caused by taking single collimators to local mode (where collimator could be moved). The local mode was tested individually for each front-end in January 2010 and in a random sub-set of collimators in 2012.

Summary: Test Local Mode Interlock

  Year     Result  
  2017     Result:  
2016    Result documented in LHC COLL e-log 23 Mar 2016  
2012    Tested in a sub-set of collimators, results documented in LHC e-log   
2010    Result documented in LHC e-log   

Test Power Cut and PRS Reboot Interlock

Check correct interlock response to a power cut and a reboot. Verification that the chane of status of the PRS untis causes an interlock whenthe PXI is rebooted. The software implementation is the same for all the units, therefore the tes on one unit is considered sufficient. It's possible to try 2 types of reboot: (1) software and (2) hardware (power cut). The same behaviour is expected for the two cases as far a s the interlock response is concernd. The hardware reboot alsos causes a reboot of the PXI that controls the MDC.

Verification followed:

  1. PXI rebooted.
  2. Beam permit removed.
  3. MDC errors (motors blocked).
  4. Connection error (collimator appears in blue in the status).
  5. Collimator unconfigured (red in the status) while reboot takes place.
  6. Collimator back to operation and interlock clear after reset.

Summary: Test Power Cut and PRS Reboot Interlock

  Year     Result  
  2017     Result in LHC COLL e-log 27 April 2017  
2016    Result documented in LHC COLL e-log 23 Mar 2016  
2012    Tested in 1 collimator, documented in LHC e-log  
2010    Result documented in LHC e-log   

Test temperature interlock

Summary: Test temperature Interlock

  Year     Result  
2017    TXT    Collimators with Block Connections XLS  
2016    TXT   
2012   JIRA COL-17 and XLSX   
2010    Result documented in HTM  XLSX   
2008 Done manually end of 2008 for 80 installed collimators

Test RBAC interlock

Summary: Test RBAC interlock

  Year     Result  
2017 Tested
2015 Tested
2012 Tested
2010 Tested

Test MCS-Collimator role

Only MCS-collimator can change MCS thresholds: EnergyThreshold, InterlockThreshold, InterlockThresholdFunct for the active beam process. Tested systematically during collimator remote commissioning (non-authorized persons frequently calling persons with MCS-collimator role to move collimators out of interlocked status). See for example LHC e-log page

Summary: Test MCS-Collimator role

  Year     Result  
2017 Tested
2015 Tested
2012 Tested
2010 Tested

Test Crystals Goniometers Interlock

Summary: Test Crystals Interlock

  Year     Result  
2017 Tested LHC COLL e-log: 27 april 2017

The MP reporting for the LHC collimation system is done in the MPP home tracking web page (linking back to the present page).

May 2017
S. Redaelli, B. Salvachua, G. Valentino