Minutes of the LIS Section meeting held on 24^th June 2013

Present: Fanouria Antoniou, Gianluigi Arduini, Hannes Bartosik, Elena Benedetto, Michael Bodendorfer, Cedric Hernalsteens, Alexander Huschauer, Michel Martini, Yannis Papaphilippou, Tatiana Rijoff, Guido Sterbini, Letizia Ventura, Raymond Wasef

General Information (Gianluigi)

CERN Medium Term Plan and 2014 budget approved by the Council. The Medium Term Plan includes the first phase of the High Luminosity LHC Project.

Livio Mapelli will replace Philippe Bloch as PH Department Head from 1/1/2014 until end of 2015.

LHC activities: 25% of splices in Sector 56 will need to be redone (less than 10% due to high splice resistance the rest mostly for mechanical non-conformity). A vacuum leak has been detected on a spare RF module supposed to be installed in the tunnel to replace a faulty module. The module will be repaired and fully tested before installation in the tunnel.  

Round Table (all)

LEIR (Michael)

The injection section (between the magnetic septum and the ETL line) as well as the vacuum sectors 1 and 2 are going to be vented. Cabling for the upgrade of the control system (in particular for the power converters) is going to start. A proposal has been made to have the Schottky signals and controls available remotely in CCC and to extend logging to include more parameters. The MD note on the measurements of the effect of the LINAC3 Tank 2 RF phase on injection performance is being finalized.

SPS and Neutrino activities (Fanouria, Hannes, Yannis)

The status of the HP-PS has been presented at the LAGUNA-LBNO general meeting at CERN. Orbit and tunability studies are complete and should conclude the single particle dynamics studies. Antoine Lachaize has started to study acceleration and longitudinal dynamics. Javier has started to study collective effects in collaboration with ICE. The possibility of a new transfer line from SPS LSS6 pointing to the North Area is being considered too. This would require superconducting magnets. In his presentation Simone made clear what are the possible intensity limits in the SPS and PS.

An Engineering change request has been submitted for the cabling of a corrector in the injection region to reduce the orbit distortion induced by the injection dogleg (optimized for the Q26 optics) for the Q20 optics: Interlocking might be required.. A review of the SPS High Bandwidth Feedback effort will take place at the end of July (30/7)

Yannis attended the Workshop on "Methods of Chaos Detection and Predictability: Theory and Applications" in Dresden. The workshop gathered together participants from several branches of physics. The URL of the workshop is:http://www.mpipks-dresden.mpg.de/~mcdpta13/ . Among others parametric distributions representing Gaussian distributions with tails were discussed.

PS (Alexander, Cedric, Guido, Letizia, Simone by e-mail)

The vacuum chamber for magnetic unit 57 will be replaced with the same type of vacuum chamber installed for Section 22 for standardization purposes. The aperture is compatible with the requirements for the extraction.

New amplifiers for the transverse feedback will be delivered in 2015. The existing cabling is compatible with the new amplifiers and. Only the replacement of the matching network might require a short access when the new amplifiers will be installed.

Two new sextupoles will be installed (in addition to two existing MTE sextupoles installed at maximum horizontal beta function) at maximum vertical beta functions for the independent horizontal and vertical chromaticity correction instead of using the Pole Face Windings (PFW) and Figure of Eight Loop (F8L) that heavily affect also non-linear chromaticity. The control of the working point could then profit of these additional correctors to control chromaticity while minimizing non-linearities in particular at injection and for the vertical plane and at extraction at 26 GeV during the rise of the extraction bump where this is difficult with the PFW/F8L only. In addition these sextupoles could be used to implement a fast chromaticity jump at transition but the feasibility of that has still to be studied in detail.

From Simone (e-mail)
LIU

SMH16 -> Finance Committee approved the works. The work will start next week with some drilling to improve the knowledge of the sites were the pillars will be built Rte Goward -> nearly finished. The asphalt will be laid in the next weeks, then a second layer only when the SMH16 works will be finished. In the meantime the services (lights, fences, etc... ) will be finalized. The parking space will remained occupied by the workers for the SMH16 worksite.

Skew sextupoles -> four dedicated power converters has been ordered. Still open the issue with the 4th magnet. For the cabling, a first temporary solution is under investigation.

Magnets -> Dominque (SU) promised to have a look again with the other Dominque (magnets) to organize at first the measurement of the measurements magnet.
Then, depending on the results and the schedule of the magnet refurbishment, more magnets might be measurements. At max, 7 will be removed from the tunnel but depending on the dose on the magnet and space available in the magnet refurbishment facility, the final number might change.

RF -> meeting for the consolidation of the 40-80 MHz system (PC) took place last week. A better set of specifications is needed to finalize the design. Deadline for september. First prototype available with more voltage for 2016.
Finalised the shielding for the longitudinal damper.

BI -> Internal review in september. Big issues concerning the schedule of different installations (like for the BWS in all the injectors) due to internal BI problems. The review is meant to improve the planning within BI taking into account the requests from the projects and OP.

Space Charge -> Nicolas finished first tests with the Lausanne cluster. Single machine faster by about 20-30% then ENGPARA but the parallelisation not working yet.
New Giovanni's student started to investigate the possibility to do SC simulations on the GPU we acquired for e-cloud studies.

RLIU -> postponed to late October.

Fluka activities -> New tech student in Fluka team to take over the work of Sanja who is leaving for GSI at the end of September. Work will be concentrate on: a) new internal dump; b) new ralentisseur (injection dump); c) new dump/scraper in SS75 (second priority). The fluka geometry of the PS will be stored in a directory free to access as for the optics repository.

HI-Intensiy-> presentation to the Laguna collaboration meeting about the PS high intensity related issues. For me the outcome of the discussion is that Ilias did not
clearly explained to Andre that we are not going to do the studies to solve the issues of the high intensity but only to highlight the study needed and to make a list of the issue. For example, Andre was convinced that MTE at 4e13 was already for sure available. As there were no issues to accelerate up to 4e13 with the existing RF system.
I discussed with Ilias to make the point and Roland confirmed that with the current situation we are going only to say what are the issues to be studied.

Impedance -> first non formal meeting with Mauro, Elena and Benoit. Agreed on plan, even if Elena will be away two next months. Mauro finished the kickers, will continue with RF cavities. Benoit will do the septa.

MSWG

2 meetings since last section meeting. See minutes.

MTE

Antoine will continue the analysis on for the machine modeling at 14 GeV/c.
Most probably the new power converter for the extraction bump will be acquired by PS-LIU

Alexander has attended a course on Medical Applications at the USPAS. He was rather disappointed to find out that the programme of the course was different from the description given at the time of the registration.

PSB (Elena)

The dynamics of the particles filamenting longitudinally close to the separatrix and generated during the longitudinal painting might be at the origin of the observed behaviour of the emittance evolution in the PSBooster simulations. It is not yet clear why the jumps of the emittance are not observed in the absence of aperture limits. On a question from Gianluigi Elena replied that the results are the same of the aperture limits are applied via the MADX aperture module or in ORBIT.

Vincenzo gave a presentation on the PSB Space charge studies at the last MSWG meeting.

ELENA (Tatiana, Christian by e-mail)

Tatiana is working at the impedance estimates of some of the components of ELENA. One of the main difficulties/uncertainties in the simulation results is due to the non relativistic regime.

From Christian (by e-mail)
 Conflict between ejection lines and ring quadrupoles definitely solved by several "small" modifications (increase of the extraction angle, smaller transverse dimension of ring quads, ejection kickers moved upstream, no elements in extraction line before leaving the critical region).
As a consequence, redefinition of the position of the ring and geometry of transfer lines; several iterations to make sure that enough space is available between the ring and the shielding wall;  still the transverse space needed for the cavity (amplifier attached will probably be moved to the inside of the ring) is discussed.
Version 2.0 of the ELENA layout taking this and other smaller changes into account will be presented next Thursday

Several discussions on topics related to magnet and power converters
  * Agreement that one converter is sufficient to supply current to the two bendings in the AD to ELENA line.
  * Smaller converter to be installed for the quadrupole circuits; this was triggered by discussions on protection against electrical hazards due to low voltage circuits with inductivity (see next point).
  * Discussions on pole-face rotation angles and parameters (FINT in MAD-X) to describe fringe field effects (in first order in gap height) with yoke length shorter than magnetic one;  hopefully the optics and magnet experts agree now.
Electron cooling
  * Still waiting for offer from Toshiba, which should arrive next week.
  * Reports sent by Masaki from the University Tokyo (originally from Toshiba) on field quality of the cooler in Kyoto; indeed, these reports quote a larger (relative) transverse magnetic field components than the ones in our specifications. 

COOL'13 workshop was interesting and good to get again in contact with people from the field
  * Interesting discussion in particular with people from TSR, who have reported empirical observations of electron cooling with relativistic betas about the same than at ejection energy in ELENA.  However, the electrons were "cold" coming from a photocathode and the beams were singly charged (good for us) heavy molecules.
  * Interesting discussions with A.Wolf on electron temperatures to be expected with thermic cathode, in particular, in the longitudinal plane.
BetaCool development and visit by A Smirnov at CERN: Pavel's aim is to adapt BetaCool to study bunched beam cooling with double harmonic RF. In addition, we should try to understand as much as possible the program (Michael is also interested in learning the code for LEIR applications).

BIO-LEIR (Christian by e-mail)

Adriano has sent a first version of the documentation of his work

Meeting where Joshua presented his studies on the front-end (2nd source and RFQ optimized for higher betas at the RFQ entrance)

Next Wednesday, Detlef and myself will meet Ranko Ostojic (did originally optics and magnet design studies for superconducting cyclotrons) to discuss whether cyclotrons could be envisaged as LEIR injectors (I doubt that there are sufficiently versatile cyclotron providing sufficient current)

Monday, 1^st July 2013 at 14:00 in room 6-R-012

Agenda:

General information (Gianluigi)

PSB optics measurements (Meghan)

Update on space charge simulations in the PSB (Elena)

Round Table (all)

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