Minutes of the LIS Section meeting held on 8th September 2008

Present:  G. Arduini, S. Aumon, J. Barranco, E. Benedetto, O. Berrig, C. Carli, M. Chanel, S. Gilardoni, M. Martini, S. Maury, E. Métral

General Information (Gianluigi)

Another synchronization test has been performed during the past week-end (5-7 September) to bring Beam 2 from point 8 to the dump in point 6. The test was perturbed by some electrical problems (temperature gauge on transformer in Point 8) determining the loss of the cryo conditions in Sectors 78 and 81. In spite of that the beam could be extracted to the dump. Another polarity error has been found in the database. Beam 1 has been injected as well and transferred up to point 5 to the tertiary collimator in front of CMS.

Preparations are ongoing for circulating beam on 10/9.

Highlights from HB08 (Elias) - slides1 - slides2

A power of 0.5 MW has been achieved at SNS. The design power is 1.4 MW. With the intensity increase phenomena like e-cloud build-up start to appear. Gianluigi asked whether injection losses are still an issue. It seems that this is the case.

After the meeting Christian send a few links on papers concerning the injection losses observed at SNS:

   http://cern.ch/AccelConf/p07/PAPERS/THPAS076.PDF

   http://cern.ch/AccelConf/p07/PAPERS/THPAS078.PDF

he also noted that the nominal bunch intensity has been almost achieved as reported at EPAC08:

http://cern.ch/AccelConf/e08/papers/thpp085.pdf

Elias presented the summary slides for the Sessions on "Beam Dynamics in High Intensity Circular Machines". One recommendation at the workshop was to avoid transition crossing whenever possible (either by staying belo or above transition or by designing a lattice with imaginary gamma transition.

Elias presented also some slides on the work done by O. Boine-Frankenheim on Transverse Schottky signals from beams with space-charge and on the corresponding analysis of simulation data. Elias reported that O. Boine-Frankenheim would e interested in re-starting a collaboration with us.

Highlights from  HB08 (Michel Martini) - slides

Lattices with high phase advance have been developed at RHIC (BNL) to minimize the transverse emittance blow-up due to IBS.

Parallel space charge codes are being developed (e.g. by Adelmann who will be at CERN in November).

Michel has discussed with F. Jones about the results of the benchmarking between ACCSIM and ORBIT. The algorithm used in the two codes are different but still the reason for the important difference between the results provided by the 2 codes is not clear. F. Jones is going to investigate that, he suspects some potential problem in the treatment of the longitudinal distribution in ACCSIM.

Round table (all)

PS (Simone)

A vacuum leak developed on the push-pull bellow of the horizontal wire scanner 54. No spare could be found by the BI team and therefore a blind flange has been installed instead. Only 2 wire scanners are now available H64 and V85. The other vertical wire scanner cannot be used because it is equipped with a new electronics.

The tune measurement is no more working the last spare DSP card broke. Work is now ongoing to make the BBQ operational. One of the main issues is the control of the excitation. It is no more possible to control the tune measurement kicker either. There are plans to use the transverse damper as exciter.

Next meeting

Monday, 22nd September 2008 at 10:00 in room 354-1-001

Agenda

General Information (Gianluigi)

Status of LINAC4 to PSB injection studies (Christian)

Round Table (all)

A.O.B.

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