Minutes of the Booster Commissioning Working Group held on 8th of January 2009

Present: W. Weterings, J. Borburgh, C. DeAlmeida Martins, Y. Kadi, C. Carli, T. Hermanns, K. Hanke, B. Mikulec.


  1. Communications
  2. Follow-up of open actions
  3. Status of dump designs and intercepting devices for Linac4 and transfer lines (Y. Kadi)
  4. AOB

1. Communications

The minutes of the last meeting have been approved.

It has been decided to combine the Booster Commissioning work package descriptions for the nominal and ultimate performance in one document. This document has been prepared for the approval process.

Reminder: PSB Review with Linac4 on 15th/16th of January.

2. Follow-up of open actions

  • Lead distributor: The removal of the lead distributor will take place during the 2009/2010 shutdown (still to be organised). Replacement vacuum pipes should be available, but still have to be found. G. Vandoni is following this up.

3. Status of dump designs and intercepting devices for Linac4 and transfer lines

Y. Kadi explained that the most advanced dump design is the one for the Linac4 dump. The composed material and the dimensions are already available (49 cm intercepted iron slabs, air cooled with 1.5 m thick surrounding concrete shielding). The only open points are thermo-mechanical studies.

The next priority will be the design of the PSB injection dumps. Due to the extremely limited space combined with high losses (in particular for head dump if no special chopping scheme is used), this design is very challenging. This dump is not a simple beam stopper, but has the constraint to protect the magnet. In reality, the assembly comprises 6 dumps (for 4 PSB rings plus head and tail dump). Due to the activation probably no repair in situ will be possible; therefore 6 spares have to be built in addition.

The H-/H0 dump after the stripping foil will receive a factor 10-20 less load than the head/tail dumps. It should be designed such that it can receive the full Linac4 beam for 1-2 shots maximum. Thus one has to rely on a fail-safe interlock system. The interlock system will also have to react on a chopper failure. (The interlock system should be discussed and reviewed in one of the upcoming working group meetings.)

Two additional dumps and two slits will be needed for the movable measurement bench.

LBE/LBS line dumps + slits: in the current configuration 3 slits and 2 dumps are required. This depends on the outcome of the line upgrade studies. Moreover the integration of the lines has to be further investigated as there is not much space available (in particular for the dumps as the lines end at a wall with the PSB tunnel at the other side). Once these issues are solved, Y. Kadi and his team need clear specifications for the dumps. The lines will most heavily be used during transfer line commissioning; the dump cooling has to be dimensioned accordingly.

Assigned to Start date Description State Result
T.Hermanns 2009-01-20 Provide specifications for beam load on LBE/LBS line dumps once a decision has been made on the line upgrades. EDMS Document 1056611. edit

Collimators: It is planned to design collimators for the old Linac2 transfer line. They are supposed to be movable in both dimensions. The question is whether these collimators will be able to protect the distributor from halo particles as there is no space for collimators in the distributor itself in contrary to the currently installed distributor. For this purpose the collimators have to be installed at the correct betatron phase.

Assigned to Start date Description State Result
A.Lombardi 2009-01-20 Identify appropriate positions for Linac2 line collimators to minimize activation of distributor due to halo particles. It is impossible due to space restrictions to place collimators in the Linac4 <160 MeV part. It might be possible in the Linac4/Linac2 transfer line, but first the damage potential to the PSB injection equipment should be proven. edit

It is not yet clear if one will aim for an aperture restriction in the PSB to displace losses from extraction to injection energies. In such a case a collimator study has to be made. The beamscope window, our current aperture restriction, has to be reviewed (it concentrates transverse shaving losses 30-32 ms after injection and is used for destructive emittance measurement with the beamscope).

It should be checked if the PSB dump can still absorb the ultimate LHC beam and a general increase in integrated intensity with the ultimate PSB performance with Linac4.

-- BettinaMikulec - 08 Jan 2009

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Topic revision: r5 - 2011-03-28 - BettinaMikulec
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