Minutes of the LIS Section meeting held on 4^th May 2009

Present: G. Arduini, J. Barranco, H. Bartosik, M.Chanel, P. Jackson, M. Martini, S. Maury, E. Métral, N. Mounet, Y. Papaphilippou, G. Prior

General Information (Gianluigi)

LHC status: The last SSS has been installed in 34. Interconnection work ongoing, vacuum chamber cleaning progressing and almost finished. Measurements of the resistivity at room temperature (sector 12-67) have been performed to verify the continuity of the copper stabilizer. Some outliers have been found and will be inspected. The same measurement needs to be performed for the quadrupoles. Sector 23  is now at 80-100 K è Electrical Quality Assurance to start soon. Sector 45 cool down due to start next week. The preliminary analysis of the data taken in SM18 (for those sectors for which calorimetric and electrical measurements at cold could not be performed at the end of last year) has been completed. It is not always conclusive: done on dipole magnets of sector 23 and 34. The analysis will be performed for sector 67 as well in order to compare with the calorimetric and QPS measurements to verify the quality of the SM18 data.

Help is needed for access and patrols for LHC. All Section members (staff and not) are welcome to contruibute. Action: all section members

L. Bruno (Radiation Safety Officer) and P. Carvalho Correia (Departmental Space Manager) have been charged to identify the Department needs in terms of radioactive material workshops and storage. C. Mastrostefano is the ABP contact for these matters. After some discussion it seems that there are no specific requirements for LIS.  

From IEFC:

• SPS scraper: request to define the future requirements for the SPS scrapers to the MSWG. Gianluigi noted that studies have been performed by H. Burkhardt and functional specifications for the new scrapers have been written by Helmut and Gianluigi in 2006. Paul replied that operational experience should be gained on the present system as an input for the new design.
• SPSC report (S. Maury and L. Gatignon). New SPSC Chairman: C. Vallee from Marseille.
• CNGS: as a result of the earthquake a delay by ~1 month is expected on the experiment side
• Impact of a long run on equipment: LINAC2 (R. Scrivens). The risk of running without full maintenance of the source will be taken. For the moment maximum length of the run is 10 months. Preventive maintenance will be limited to the change of the cathode (3 day stop).
• REXTRAP consolidation (F. Wenander). It seems that not all the money and manpower is available. A small project will be set-up and money (65 kCHF) requested.
• CNGS target remote inspection with cameras (I. Efthymiopoulos): an increased torque has been measured when trying to rotate the target and for that reason it has been decided to inspect the target with cameras after lifting it (the remanent radioactivity is 40 mSv/h after some months of cool down!). Rust has been seen on the ball bearings. Modifications for the spare will be studied. The target has been put back in place in the same position as last year. In case the target should break a 1 month stop is needed to allow for cool-down and two options are possible: 1) move the target with some special instruments manually (preferred), 2) replace the target with the spare (if a solution has been found).

After some measurements on the movement of the soil of the TT20 tunnel made by ABP/SU and discussion with C. Podevin a TT20 re-alignment during long SD 2010-2011 is needed. N. Gilbert has been informed and will follow that up.

Gianluigi reminded the staff members about the deadline for the submission of requests for fellows (Wednesday 6^th May at midday).

At the last SPS Upgrade meeting (21/04/2009) M.Benedikt made a request to provide the minimum and maximum values for the transverse emittances acceptable by the SPS for the fixed target beam in the PS2 era. Gianluigi has written a first draft and will circulate it to Elias, Giovanni and Yannis for comments.

 Round table (all)

From Elena Wildner at PAC:

• finalization of the runs and analysis of the energy deposition dependence on magnet aperture for the LHC upgrade phase II for PAC poster and paper;

• contribution to organization of nu-factory

• barrier bucket studies for the decay ring for the Beta Beams Study

• preparation of the talk for the "Physics Opportunity" Workshop at CERN

• preparation of the talk for the SPC on the gamma dependence issues for beta beams

• finalization of the work programme for the two trainee students coming in June.

Michel Martini said that the problem of the discrepancy between the MOCAC (IBS calculation code re-written in C++ by A. Vivoli) and classical formulas for IBS has been understood and it is due to the post-processing of the simulation data. Reprocessing of the data and increasing the number of cells for the calculation to 4800 (maximum possible, above this value the programme crashes) allows obtaining comparable results for an SPS cell.

Michel Chanel has done some work on the LHC beam in the PS Booster. He has obtained a smaller than nominal vertical emittance and asked whether this could be useful for the downstream machines. After some discussion it became evident that, although a smaller emittance can enhance collective effects like space charge at injection in the PS or electron cloud instability in the SPS at injection, it is better to have a small transverse emittance at low energy in the PSB for machine studies, furthermore the it can be blown-up during acceleration in the PSB with the transverse feedback.

Gianluigi asked whether there are news about the vacuum degradation in the electron cooler section in LEIR. Michel Chanel replied that gas analysis is ongoing and that results should be known soon and a discussion with the vacuum team will take place tomorrow. Cold Check-Out due to start at the end of May. Some problems have been found with LS and fixed. S. Pasinelli (OP) is following up the controls issues.

Gersende is working with C. Rogers (RAL) for the ionization cooling part for the Neutrino Factory study. She is comparing the ICOOL and GEANT-MICE codes in order to determine ionization rates and therefore the maximum field achievable on the RF cavities. The maximum field achievable in the cavities affects the acceptance of the cooling channel (the lower the field the lower is the acceptance). For teh moment ICOOL (written at FNAL/BNL) is providing more pessimistic results.

PS (Yannis): no major problems, but the wire scanners are not yet operational (e.g. the energy is not taken into account properly). The SEM wires remained blocked in the TT2 line. This was due to a problem with the compressed air. The orbit acquisition (CODD) is working well. The offset observed in the reading provided by the pick-up 20 and 57 was due to dust in the connectors and it has been fixed by applying some HV to the connectors. The measurement of the matrices for chromaticity correction is ongoing. The new regulation for the main power supplies is working well. Gianluigi asked whether the new OTRs in TT2 are working well. Yannis will verify that.

Nicolas is continuing the theoretical analysis of the electromagnetic fields in a cylindrical pipe with resistive wall. He has also developed a technique to provide accurate FFT of analytic functions over 15 decades.

SPS (Elias): beam based alignment performed. r.m.s. less than 1.5 mm in both planes after alignment. Electrostatic septum (ZS5): problems observed (short to ground of an ion trap and aperture limitation. After opening it was found that (either during transport or installation) the ion trap was again bent and a contact to ground occurred). Repaired in-situ. After the intervention it seems that both problems (short to ground and aperture) are fixed. Some tests are being performed on a multi-strip detector installed in the roman pot to be used for the UA9 (crystal experiment). The signal is not yet totally understood. Further tests are necessary. During the (long) week-end the TT20 transfer line was started to be adjusted and the beam was seen on the T2 target. This work will continue during the coming week (to be ready to send beam to physics on Monday 11^th) and several issues (such as polarity switch control of some magnets in TT20 etc.) will be followed up. A SEM grid used in TT20 is not appearing in the TT20 model. Action: Olav

Aperture measurements have been performed with thw wire scanner 416. Gianluigi noted that in the past problems were found with that wire scanner (calibration) and the calibration should be verified before using the data from that wire scanner for aperture measurements. Gianluigi suggested to use wire scanner 51995 or wire scanner 414. Elias said that the wire scanner 517 is not yet working (since last year).

The economy cycle has been tested and it is now used in operation.

Gianluigi asked Elias whether he had some feedback from GSI after the workshop in February and the proposals for collaboration sent by Elias to O. Boine-Frankenheim. Elias replied in the negative. He also added that IBS could be an additional subject for collaboration with GSI. 

Impedance meeting taken place last Friday (profiting of B. Spataro visit) - link. The results of the simulation/measurement benchmark for the SPS BPMs has been presented (the agreement is good) as well as the status of the comaparison of the particle studio simulation data for rectangular and cylindrical vacuum chambers with resistive wall with theoretical formulas. Elias noted that the quadrupolar term of the kicker wake field might not be correct due to the presence of the conductors whose effect is not taken into account in the formulas used for the estimate of the wake fields of the kickers. Gianluigi suggested to contact B. Doliwa to see whether he could quantify the effect of the conductors in the simulation of the quadrupolar term of the wake field (Doliwa had made some impedance calculations for the GSI kickers in 2006). Elias will contact him.

 Next meeting

Monday, 18^th May 2009 at 14:00 in room 354-1-001

Agenda:

• General Information (Gianluigi)
• Status of Nominal Ion beam in LEIR (Michel Chanel)
• Round Table (all)

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