Participants:  Simon Albright, Wolfgang Bartmann, Thomas William Birtwistle, Jean-Baptiste Bonnamy, Dario Carloni, Gian Piero Di Giovanni, Tobias Dobers, Cathryn Dunicliff, Jose Antonio Ferreira Somoza, Alessandro Floriduz, Vincenzo Forte, Matthias Haase, Jan Hansen, Christoph Hessler, Jean-Baptiste Lagrange, Bettina Mikulec, Gabor Petrika, Andrea Santamaria Garcia, Jonathan Speed.

Approval of minutes

The minutes of the LIU-PSB WG #196 were approved.

Communications

Report on the LIU Project Team meeting of the 6^th of July 2017:

• YETS schedule has been approved at the IEFC.
• Julie Coupard will present a planning proposal concerning the LS2 activities at the beginning of August.

Follow-up of open actions

Bundle actions concerning the PSB transfer lines: presented today.

• W. Bartmann  (2017-06-15) Organise discussion with BI to finalise the beam instrumentation for the BT/BTM/BTP transfer lines for the post-LS2 situation.  (go to action)
• K. Hanke (2017-06-15) Organise discussion with ABT, RP, VSC and integration to clarify remaining open points for the BT/BTM/BTP transfer line integration (vacuum equipment, shielding, supports).

Other related actions to be followed-up:

• J-M. Lacroix (2017-06-15) Complete integration of PSB-PS transfer line.
• B. Riffaud (2017-06-15) Provide a proposal for the support of the equipment in the BTP line.

Update on the PSB Transfer Lines (Christoph Hessler)

• The integration of the BT, BTM and BTP lines was previously discussed in the LIU-PSB Meeting #190 (minutes), where interferences between elements and other problems were presented. The issues presented in that meeting have been solved.
• Discrepancies between the MAD-X and Geode survey models concerning the BT/BTP lines have been found and some of them not yet completely understood. This concerns the start of the transfer lines, the position of the beam stopper, quadrupole lengths, BPM lengths and the KFAs and SMVs lengths and positions. The proposal is to use the magnetic length for the optics elements, the flange-to-flange distance for the BPMs, the starting point defined in MAD-X, and the position of the beam stopper as found in the scan 3D. The position of the elements in the BTP line could be directly defined with the new MAD-X file as the line will be completely renovated in LS2.
• New elements were inserted in the MAD-X sequence, namely: BTP.BPMW15, BTP.BCT10 and BTP.VVS20. Also, the corrector magnets BTP.DHZ10 and BTP.DVT10 will be replaced by dual plane correctors, which have also been included in the MAD-X sequence.
• The wire grid downstream of SMH42, situated in the PS injection line, currently interferes with the circulating beam. In LIU there will be even less envelope separation, and the size of the envelope will change with the injection bump. Solutions are under investigation but do not prevent the conclusion of the transfer line design.
• New BPMs will be installed around the new Y chamber in MU41 at PS injection: the BTP.BPM60 as close as possible to the Y chamber and the BTP.BPM30 upstream of the septum exit, at 90 degrees of phase advance.

Comments

• T. Birtwistle commented that there is an ongoing effort to define a mechanical model in the layout database, in addition to the magnetic model. This will allow to derive all the needed information from only one source and avoid discrepancies.
• B. Mikulec commented that most of the observed discrepancies probably come from the definition of the starting point of the transfer lines between MAD-X and Geode, and suggested to use the MAD-X starting points in all the files.
• B. Mikulec suggested that T. Dobers measures the position of the beam stopper in the next technical stop (ITS3). T. Dobers commented that the bending magnet upstream of the beam stopper (used as reference) has a longitudinal displacement of 28 mm that was discovered in the 90’s and was never corrected. He will take it into account during the measurement. The measurements should be done with respect to two different elements as an additional cross-check.
• All the information concerning the BT and BTP lines should be sent to J. M. Lacroix this week to allow him to finalise the integration of the lines. B. Riffaud will design supports and vacuum chambers based on that work.

Actions

The proposed solution is to prepare the LIU files, including all the understood discrepancies, which will define the baseline for LIU. In parallel, different experts will update and correct other files/databases (current MADX lines and Geode). A series of actions have been derived:

• Send the new MAD-X file to I. Efthymiopoulos and T. Birtwistle for the upgrade of the LIU-PSB and current MAD-X optics, and also the layout database (C. Hessler).
• Make a list of starting points of the transfer lines to be sent for approval in an EDMS document (T. Dobers).
• Measure the position of the beam stopper during ITS3 (T. Dobers).

AOB

Concerning the Tour de Table:

• S. Albright reported that different parameters for the new magnetic cycles are now in Excel files attached to the EDMS document.
• T. Birtwistle commented that the ECR concerning the turn-by-turn SEMGRIDS to be installed during the YETS 2017/18 needs to be started by F. Roncarolo, who has been informed by B. Mikulec.
• D. Carloni mentioned that there is a meeting happening on the 19th of July 2017 concerning the infrastructure of the new PSB ventilation system. The output of the meeting should be included in the safety file.
• F. Schmidt communicated that they found the location of the old PSB paper technical reports, which date from the beginning of the accelerator complex to 2010. The search for the damping resistors’ specification among these documents is ongoing. He also reported that studies for the redesign of the PSB scraper are converging. Concerning the chromaticity correction in both planes, there might be a possibility of achieving it by powering the BSW power converters next year.

Next LIU-PSB meeting on the 1^st of August 2017: Update on the cooling and ventilation systems in building 245  by Gabor Petrika. The meeting of the 15^th of August is cancelled.