Minutes of the LIS Section meeting held on 18th October 2010

Present: G. Arduini, H. Bartosik, C, Carli, P. Jackson, M. Newman, A. Lachaize, G. Prior

General Information (Gianluigi) 

·         Gianluigi reminded the section members that Delphine should be informed in due time about any collaborator visit such that the office space and computer can be prepared.

·         The necessary authorization is required to drive a CERN car. The driving licence is a necessary but it is not a sufficient condition for that.

·         Flora Meric is replacing Lauriane Bueno (she is leaving CERN for another post) at the departmental secretariat.

LHC: the luminosity goal of 1032 cm-2s-1 has been achieved and exceeded. Collisions have been regularly provided with emittances at the beginning of the fill well below nominal emittances (in general 2.5 micrometer or smaller). A test of collisions with very small emittances has been performed achieving beam-beam tune shifts of >0.02 (design value 0.015). The lifetime when going in collision dropped to 1 hour and then recovered very rapidly (less than 1 minute) to 5 hours. The beams were dumped due to a low threshold on warm magnets in the collimation area (corrected since then). A bad interconnection between two consecutive magnetic septa (warm magnets) in point 2 (injection of the clock-wise beam) has reduced the aperture at injection. An intervention is planned starting tomorrow 19/10, for that reason it has been decided to advance the technical stop.

Round Table (all)

Hannes

Looking at the magnetic measurement data obtained from J-PARC. The resulting PS2 Dynamic aperture for the given magnetic error table is of the order of 6 sigmas i.e. approx 50%  more than the physical aperture

PTC ORBIT has been installed. It needs to tested. Some tests have been done for the PSB and PS2 but for few turns. M. Martini has been running the application. Errors stored in MADX/PTC can be transferred to ORBIT. This programme provides an easier interface to orbit. PTC is not used to track particles among space charge nodes.

Gianluigi asked whether comparisons have already been done among PTC/ORBIT and ORBIT somewhere else. Not sure.

For the moment the time evolution of magnetic parameters is not included in ORBIT or PTC/ORBIT

Christian

Ion filling scheme. Discussions ongoing with Massimiliano Ferro-Luzzi for the filling scheme. There is a proposal for injection of 15 bunches in the SPS. Performance of LEIR seems to have deteriorated with time. Christian is going to investigate what is the reason for that. Christian was wondering whether the stripping foil is deteriorating. The replacement of the stripping foil last year produced a significant improvement.

A discussion for the use of accelerators for medical purposes has taken place organized by S. Myers.

Myriam and Simone

Oscillations in losses and capture efficiency do not depend on the number of MTE cycles. Test with a fixed super-cycle (no AD) is going to be performed. Stop AD mains to check whether there is any correlation taken into account that the visible frequencies in the spectrum of the evolution of the losses and capture efficiency are 0.01 and 0.02 Hz.

The stability of the MTE beam trajectory in the TT2/TT10 line has been measured. Myriam is analyzing the data. The optics of the TT2/10 line has to be measured.

Measurement on the power converters of the non linear elements has been done. Tests of the fluctuations of low energy quads will not be possible because the HW is not available in time for the tech stop.

A meeting is going to take place with BT for a spoiler to be installed in SS15.

Next meeting

Monday, 1st November 2010 at 14:00 in room 354-1-001

Tentative agenda

 

 

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