Summary Notes of the Third Meeting of Sub Working Group on the Commissioning of the Machine Protection System,
Wednesday 14th February 2007

 

 

Present: Brennan Goddard, Verena Kain, Mike Lamont, Laurette Ponce, Bruno Puccio, Blanca Perea Solano, Jan Uythoven, Frank Zimmermann

 

CC: Ralph Assmann, Roger Bailey, Bernd Dehning, Eva Barbara Holzer, Stefano Redaelli, Rudiger Schmidt, Benjamin Todd, Jorg Wenninger, Markus Zerlauth

 

 

1. Comments on the minutes

There were no comments on the minutes of the previous meeting.

2. MPS aspect of the commissioning of the vacuum system

Laurette and Bruno prepared a presentation on the MPS aspect of the commissioning of the vacuum system. They talked to J.-C. Billy and I. Laugier of the vacuum group. Laurette first gave a brief overview of the different vacuum systems to be commissioned: two ring vacuum systems (important for the MPS) and the insulation vacuum system (does not affect MPS). There are no vacuum valves in the arc between QXL and QXR, because ‘cold valves’ do not exist; there are gauges in the arcs. In total there are 300 sector valves, 800 gauges, 1300 ion pumps and 300 PLCs. For the two rings, separate beam permits are issued, except in the IRs where there is only one common user permit.

The interface of the vacuum equipment with the following systems was discussed in the meeting:

  1. RF System: this concerns equipment protection, but one needs to check that the “switch off logic” is correct (first dump beam, than switch off RF ??) or that the time constants are ok. Depending on the results from discussion, this might need to be tested. Needs to be followed up.
  2. With BI: beam gas ionisation monitor. Does not concern MPS.
  3. With Cryogenics: does not concern MPS.
  4. With Access System: the safety beam stopper is seen as a sector valve; no special requirements from MPS (just like any other sector valve).
  5. Injection kickers MKI: also equipment protection, does not concern MPS.
  6. Beam dumping system: MKD and MKB. Not clear why, as those systems can operate in air. Needs to be followed up.
  7. Beam duping system: MSD. Also needs to be checked why. Needs to be followed up.
  8. Collimation system: how does the vacuum system react on ‘fast’ spikes during collimation? Needs to be followed up.
  9. BIS: Important, see below.

 

The most important interface of the vacuum system concerning the MPS is of course the BIS, the details are given in slide 8. The signal of the BIS is verified before closing any valve. In case a bad vacuum is detected by two out of three gauges or pumps near a specific valve a beam dump request is issued (USER_PERMIT = FALSE). The BIS will create a dump request (BEAM_PERMIT = FALSE). The valve concerned will only be closed when BEAM_INFO = FALSE (issued by the BIS). The BEAM_PERMIT can be set to FALSE by the vacuum system, either when 2/3 vacuum measurements indicate a bad pressure or when the status of a valve is not closed.

 

The test procedures during hardware commissioning of the vacuum system consist of two parts:

  • Vacuum in stand alone; the BIC signals will be bypassed to simulate the closing.
  • Integration with the BIS: these procedures will be described in detail in the commissioning procedures of the BIS.

 

During the cold check-out the complete chain of Vacuum System – BIS – Beam Dump needs to be randomly checked for some of the vacuum interlock signals.

 

There was a consensus that no special tests with beam are required to test the MPS aspects of the vacuum system.

 

It was agreed to prepare a detailed test document concerning the MPS aspects of the vacuum system commissioning (Laurette, Bruno, Jan).

 

3. Format of documentation

Blanca gave an online presentation of the MTF system as it is being used for the Hardware Commissioning of the LHC. Via the LHC home page there are several ways into the MTF system. A starting page can be found here. This is the example of the status of certain tests (click the ‘installation and commissioning’ tab). The different tasks are defined in the edms documents describing the different system tests. For some items a ‘slot by slot’ view can be used for the different machine positions. Jobs can be repeated as many times as desired. All results from previous tests are preserved. Details of test results can be attached if desired, or links to edms documents can be made. The system is linked to the layout data base. It is possible to create a structure, giving a (graphical) view from a top layer (example).

 

As this is a system which is being used intensively at CERN and basically does exactly what we need for the description and follow-up of the commissioning of the MPS, it seems to be a logical choice to use this system. The only modification desired is to show a more complete description of the tests within MTF (which avoids having to link to the edms document for the more complete description).

 

It is possible to link to ‘other tests’ as performed for Hardware Commissioning, but the status as displayed under ‘Machine Protection Commissioning’ will only be updated after ‘clicking’ on it, to accept a change of status.

 

The aim is to prepare part of the structure concerning the MPS commissioning, and especially the tasks concerning the vacuum system, for the next meeting (the hardware commissioning tests are net yet defined in MTF, so one can not link to these).

 

Jan Uythoven, 19/02/07.