Meeting on Linac4 - PSB BI Line, 09-March-2009

Present:  Masamitsu Aiba; Jan Borburgh; Rocio Chamizo; Brennan Goddard; Michael Hourican; Carlos De Almeida Martins; Roberto Rocca; Luc Sermeus; Volker Mertens; Wim Weterings

Excused: Christian Carli

• Feedback from last meeting:
  • WW has contacted AL concerning a possible reduction of the BI.SMV horizontal aperture. With the current values, the ratio between the aperture and rms beam size of the DIS and SMV is around 5 for both planes. This is as low as one feels comfortable to go, so the apertures shouldn't be reduced further. CC communicated by E-mail that he proposes that one should have a look into the geometry to reduce the required field, thus stresses in the yoke, by moving the SMV upstream (~1m).
  • CC further communicated that the steering at the very end of the line has no significant impact on the transmission and the beam characteristics at the injection point. Thus, the DHV50 and DHV70 do not need to be taken into account for beam dynamics simulations.
    In the near future, a dedicated meeting will organized to discuss the required modifications on the magnets in the PSB injection line.
  • BG mentioned that simulations of a 5ms and 100µs BS chicane fall time are being prepared. This could be linear or exponential. CdAM confirmed that both cases would be acceptable for the foreseen power supply.
• RC presented preliminary results of MonteCarlo study of the head dump in the BI.SMV septum unit. Results were shown for a Boron Nitride dump, with and without copper shielding inside the vacuum tank. Considering a 60µs rise time, the equivalent dose at the vacuum tank is in the order of 100-1000 mSv/hr after 200 days of operation with a reduction of a factor 10 after 1 week of cooldown.
• In previous meetings, proposals for removing the Head Dump from the SMV system were shown and this meeting JB presented a cost estimate for option 2, extraction of the pulse rise time by installing a 4th SMV magnet. The total Total additional cost would be ~240 kCHF, and the advantages of less radiation for the magnets, no detrimental vacuum effects, independent intervention possibility on BISMV magnets and dump and the reduction of the head dump functionality (no magnet protection required) were mentioned. Also an external dump would increased the shielding possibilities.
  CdAM mentioned that, in case this 4th BISMV would be powered in series with BISMI1, no or small financial impact would occur on the power supply. In case of powering these magnets in series, BG reminded that one should include the tuning possibilities of BISMV1 in the dump acceptance.
  RC mentioned that the financial impact on an external dump can not yet be estimated, since no design has been made for this case.
• Due to the design changes of the BIDIS magnet and vacuum tank, MH mentioned that the DVT40 can not be supported anymore. This shall be discussed in the dedicated 'magnet meeting', mentioned above.
• After successful manufacture of a BIDIS prototype coil, the series production of the BIDIS coil has now been launched.

WW