Minutes of the LIS Section meeting held on 06^th May 2013

Present:Androula Alekou, Fanouria Antoniou, Gianluigi Arduini, Hannes Bartosik, Michael Bodendorfer, Christian Carli, Adriano Garonna, Alexander Huschauer, Michel Martini, Meghan McAteer, Tatiana Rijoff, Guido Sterbini, Letizia Ventura, Raymond Wasef

General Information (Gianluigi)

Reminders:

• The deadline for the submission of the IPAC13 papers for the section/group/department approval has passed. Action: submission of the remaining papers ASAP - all those who have not done it yet.
• Collection of requests concerning data logging and data analysis tools should be sent to Richard Scrivens by the end of this week with copy to Gianluigi
• The ABP Group meeting will take place on Wednesday 19/6 in the morning and it ill be followed by a barbecue.
• Gianluigi will be absent from Friday 10/5 afternoon for IPAC13. He will be back on Tuesday 21/5.
• Gianluigi encouraged all the members to document in MD notes the results of the experiments conducted in the last run as soon as possible. Publication in refereed journals should be considered as well for studies where a good set of experimental and theoretical/simulation data exist.

Simulations of the LINAC4-PSB Injection in the presence of Space Charge (Michel) - slides

Space charge has been included from the beginning already during the injection process and it has the effect of "diluting" the phase space in the transverse and longitudinal plane. The injection occurs in a non stationary bucket (the derivative of the magnetic field is non zero during the injection process as it is now for the PS Booster).

The losses observed with the Inconel vacuum chamber (for these simulations the space charge was not considered during the injection process) can be reduced by changing the working point from 4.55 to 4.45 but the blow-up. The losses are insensitive to the working point with the standard vacuum chamber. The emittance blow-up for the Inconel vacuum chamber is always larger than that for the standard vacuum chamber. The horizontal and vertical blow-up increase when changing the working point from 4.55 to 4.45.

The particle lost in the aperture are those with small amplitude in the horizontal and vertical plane (hence having the largest tune shift) and those at large negative momentum deviation (i.e. those which are not captured and having large positive radial position according to MAD convention - the dispersion is negative in the PSB due to the counterclockwise rotating beams).and large vertical deviation.

Gianluigi asked to indicate explicitly the beam parameters (in particular bunch population) at which the calculations have been performed. It would be good to plot also the space charge tune footprint for the cases considered.

There is an issue with the definition of RF phase in PTC. By default the stable phase is always set to 0. Gianluigi suggested to contact L. Deniau for that.

The effect of the longitudinal cut seems to indicate that the calculation of the emittance is affected by the particles at large amplitude in the longitudinal plane (i.e. those which are not captured)

Round Table (all)

LEIR (Michael)

Michael has completed the analysis of the evolution of the vertical chromaticity during the LEIR cycle. Positive chromaticity is measured in the vertical plane. Gianluigi asked whether the BBQ signal shows signs of vertical oscillations. Michael replied that this should be looked at.

Christian said that in the past the peak detection signal  did not reveal signs of instabilities.

Michael added that the possibility to measure chromaticity in a more automated way is being discussed with the RF and OP colleagues. The possibility to make the Schottky signal available in CCC is being investigated. This might imply replacing the spectrum analyzers for the Schottky measurements.

PS (Alexander, Guido, Letizia, Raymond)

Guido is mostly working on CTF3 as agreed.

Alexander and Raymond are working on their presentations and posters for IPAC13.

Letizia is working at implementing a more realistic model of the impedance of the 10 MHz cavities to include the amplifier chain to provide more realistic simulations of the coupled bunch longitudinal instabilities.

ELENA (Christian, Tatiana).

Technical Design Report: all parts received except vacuum, RF and beam instrumentation.

BIO-LEIR (Adriano, Christian)

Configuration reviewed to make the magnetic septum strength requirements more reasonable. The requirements on the bumper magnet might have to be reviewed as well

Compatibility with fast extraction must be analyzed in detail

PS Booster (Meghan)

The analysis of the orbit response data is progressing well and the IPAC13 presentation will be updated.

LAGUNA-LBNO (Androula, Fanouria)

Work on the HP-PS is progressing. Chromaticity correction is being studied. Androula is getting familiar with the software used by J. Barranco for the collimation studies for PS2. The coupling observed in the trajectory of the extracted beam for the Short Baseline experiment using the LSS2 extraction and the injection kicker in the SPS remains unexplained so far.

SPS (Hannes)

Hannes is progressing with the writing of his thesis

Next Meeting

Monday, 3^rd June 2013 at 14:00 in room 6-R-018

Agenda:

General information (Gianluigi)

Update on the simulations of the LINAC4 - PSB injection in the presence of space charge (Vincenzo)

Round Table (all)

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