Minutes of the LIS Section meeting held on 26^th July 2010

Present: G. Arduini, S. Aumon, C. Carli, H. Bartosik, M. Newman, Y. Papaphpilippou

General Information (Gianluigi) 

Fellows: a meeting has taken place to review the fellow requests for the various groups. It has been decided to stabilize the fellow distribution to the present numbers. This means that ABP quota will stabilize to about 20 fellows/year corresponding to ~34% of the overall BE quota!

Achieved >1.5x10³⁰  cm^-2 Hz with 12 bunches/beam. Next steps to go to 24 bunches with bunch train injection from SPS (4 bunches/train). At present recovering from technical stop. First evidence of top quark candidates presented at ICHEP2010

More information can be found in the LHC commissioning web page

Gianluigi has asked the machine supervisors to continue to distribute the weekly summary on the status of the machines to all the machine supervisors including those in the ICE section.

SPS (from Elias):

2 magnets were changed during the technical stop.

Machine development session:

• successful test of the newly installed LHC collimator with button pick-ups,

• successful UA9 run with good efficiency and rapid re-establishment and improvement of last year performance with new goniometers and crystals;

• the installation of a stainless-steel reference line with electron cloud monitor took place but the LHC beam high intensity run was hampered by the high outgassing of the kapton present in the electron cloud monitor. The area had to be re-opened and the kapton removed.

• and MD with 50 ns LHC beam and intensity well above nominal had to be cancelled due to an inter-turn short on a main dipole coil. the magnet was changed on Friday and the machine was back in operation on Saturday for LHC filling.

Round Table

• Yannis:
  • PS MD last week to verify whether the observed fluctuation of the magnetic field at injection could be related to the effect of the pole-face windings of the reference magnets. The results are not conclusive but it seems that this cause can likely be discarded.
  • RF team has produced a 150 ns beam with nominal bunch intensity. Some more work is required.
  • Simone is trying to set-up a MTE cycle with electrostatic septum to minimize the losses on the magnetic septum.
  • PS2: studies on the large wide-band RF cavities ongoing. Draft of the conceptual design report to be prepared by the end of September
  • Non-linear dynamics conference in Greece. Various aspects were covered. New methods and tools were presented not only from accelerator physics. New tools and parameters for defining a chaotic behaviour and speed-up dynamic aperture estimations. Link to the conference: http://nonlinear.web.auth.gr/
  • MD4 status: not clear whether this cycle has been fully re-established after the controls problems occurred last week.
  • Themis Williams (staff child) has been working on the 1000 turn measurement with BPM turn-by-turn data from PS under the supervision of Hannes and Yannis.
• Sandra:
  • PS Injection studies: The ringing observed on the LHC BLM signal in the injection regio is an artifact. The time response of the LHC BLMs is slower than that of the ACMs and the losses of the individual bunches cannot be resolved. The sensistivity of the LHC B:LM is also poorer so that the turn-by-turn losses occurring right after injection are hardly visible. 1/3 of the losses seem to occur right at injection and the rest is distributed over few hundreds turns. Gianluigi and Christian suggested to look whether there are means to change the beam size at the injection septum by modifying the optics in the injection transfer line or by acting on the emittance of the beams. A presentation on the status will be given at the next meeting.
• Miriam:
  • finishing the data analysis of the MTE . For the moment no clear explanations of the fluctuation of the losses.
• Christian:
  • LEIR should take beam next week. Some co-ordination issues for the shut-down. Water valves have been installed to have the possibility to minimize the flow on magnets and give more margin for the operation of the LINAC/LEIR water station, but the type of valves installed in not apt.
  • Problems with the LEIR controls have been found (InCA) and they are being fixed.
  • Beam instrumentation is working. The remote acquisition of the Schottky spectra has been fixed by OP (S. Pasinelli). but the robustness with respect to network load and with respect to versioning of the Operating System (Windows XP) have to be addressed to guarantee long term maintainability. To be discussed with BI
  • 18 GHz source tested but X-rays level too high ==> stopped by RP. No time to install additional shielding for this year.
  • The plasma chamber is now stainless steel and the source seems to be more stable with reasonable current (20 microA at the end of LINAC3)
  • LINAC4: the note on LINAC4-PSB RF interface is being reviewed by P. Baudrenghien. New simulations with ORBIT need to be launched to study the effect of a slower energy modulation as proposed by the LINAC4 team. The configuration for the injection hardware is being finalized and agreed with ABT. The idea of having a larger painting bump proposed by Christian and Michel in order to minimize the risk of accidental damage of the injection foil after injection has been included in the design. Activation studies in the PSB and the study on a possible collimation system are progressing slowly and remain one of the main concerns
  • Christian has been contacted by M. Dosanjh and M. Silari who have confirmed the interest for a faciility for radiobiological studies at CERN at LEIR. A request for a study will be submitted.

  Next meeting

Monday, 9^th August 2010 at 14:00 in room 354-1-001

Agenda

• General information (Gianluigi)
• Injection studies (Sandra)
• Round table (all)

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