Minutes of the LIS Section meeting held on 21st April 2008

Present: M.Aiba, G. Arduini, S. Aumon, J. Barranco, E. Benedetto, C. Carli, A. Franchi, S. Gilardoni, M. Martini, S. Maury, E. Métral, Y. Papaphilippou, D. Quatraro

General Information (G. Arduini)

The dates for the TI8/TI2 tests with beam have been defined:

The beams should be prepared in the injectors for these dates. This would require testing the controlled transverse emittance blow-up in the SPS. Elias will follow that up.

Floodings have been observed in some points of the SPS, in particular in point 5 where some crates have been damaged. The control crate for the LHC BPM in LSS5 will be unavailable at least until the end of May.

Round table (all)

NA61 fixed target experiment with ions in the North Area: Stephan had another meeting with the spokesman and the SPS physics coordinator. At the end NA61 agreed that they would use the same ions as ALICE. Lead ions for fixed target physics can be delivered not before 2011. In that case ion fragments will be used and a proposal has to be re-submitted by NA61 to the SPSC.

SPS impedance: another meeting has taken place on 17/4/2008. The minutes are available in the new SPS Impedance web page maintained by Benoit and Elias. They are planning to update regularly the SPS ZBASE impedance DB with the existing information: kickers with analytical models from Elias, items for which simulation data from B. Spataro exist  (BPMs have been finalized, pumping ports, TWC200 MHz, IPM, TWC800 MHz are almost complete) with the results of the simulations from B. Spataro,

Gianluigi mentioned that in the future it will be important to extend this effort to the other machines and in particular it would be important to have the status of the understanding of the PS Booster impedance. M. Chanel will give a presentation to the section by the end of May.

Simone mentioned that the power supplies of the bump 16 (as a modification for the MTE we have 4 independent power supplies, one for ach of the 4 bumpers) have been tested and a spread in the length of the pulse by ~160 microseconds (total length ~6 ms) has been observed and needs to be compensated with other correctors (also installed for the MTE). An additional difference in the length of the magnetic field pulse seen by the beam might come from the different shape of the vacuum chambers of these magnets.

Simone mentioned also that some of the new power supplies installed for the MTE and for the powering of the doublets for the gamma jump have not been connected to OASIS. A tempoprary fix has been found for the time being but new channels will have to be installed. This will happen only in 2 months.

Gianluigi asked whether it is planned to start the machine with the new regulation for the main power supplies. Simone replied that we will start with the old regulation and tests will be performed during the run. Next year we should start with the new regulation system.

Yannis presented the preliminary results of the analysis of the raw data taken with the BBQ last year. The FFT performed in the BI expert programme shows clearly a "quantization" of the values which are grouped in pairs. The Fourier analysis performed by Yannis does not show this behaviour. Michel Chanel and Elias suggested to look at the methods described by Asseo and later by Giovannozzi. Yannis mentioned that the these methods should be similar to those he used but he will verify. Gianluigi noted that once we have tested our tools and we show their superiority with respect to the existing ones we should ask to have them implemented in the tune measurement applications.

Gianluigi asked whether the BBQ system has been connected to the damper pick-up. Simone replied in the negative, therefore it should be possible to commission the transverse feedback without problems this year.

Masamitsu he has developed a new ORBIT routine to estimate the temperature of the stripping foil for H- injection for the LINAC4 to PSB injection studies.

Michel Chanel mentioned that the PSB start-up with beam is imminent and for the moment it is delayed by a general control problem. Michel is also looking into the design of the bumpers and septa for the PSB in view of the upgrade of the PSB Injection for LINAC4. He is in contact with J. Borburgh.

Christian and Michel (together with Giulia) are also looking into the optics of the last part of the injection line from LINAC4 to PSB to optimize the beam size at the septa and distributor and minimize the losses.

Giovanni has made the modifications to the HEADTAIL code in order to provide the possibility of dumping the turn by turn beam centroid positions at any BPM in order to study the expected dependence of the phase advance vs. intensity in the presence of localized sources of impedance and therefore finalize the algorithms for the analysis of the data collected in the SPS.

Sandra is setting up the tools for the analysis of the losses in the PS injection line.

Javier is starting to work on the expected loss maps for the PS2 for the present FODO lattice.

Gianluigi reminded the machine supervisors to send the operation week summary also to the members of the section.

 

Next meeting

Monday, 5th May 2008 at 10:30 in room 354-1-001

Agenda

General Information (Gianluigi)

PSB beam-based realignment (Giovanni)

A.O.B.

Back to Minutes