Minutes of the LII Section meeting held on 10^th April 2006.

Present: G. Arduini, S. Aumon, G. Bellodi, O. Berrig, H. Braun, R. Bruce, C. Carli, M. Chanel, S. Gilardoni, J. Jowett, M. Martini, J. Pasternak, F. Roncarolo, G. Smirnov.

Conclusions of the Working Group on Beam Losses and Radiation  (G. Arduini) (slides).

Study of the losses in the TT2-TT10 line for the Fixed-Target and CNGS beams (S. Gilardoni) (slides)

The beam profile of the CNGS beam has been tracked through the TT2 and TT10 lines taking into account the trajectories of the five slices. Aperture restrictions are mainly located at the beginning of the TT10 line (MAL1001 and QIID1003) and at the end of the TT10 line (MAL1029). The reduction of the aperture due to the trajectory of the different slices is limited, the largest effect is due to the beam size. A reduction of the beam size by an appropriate re-matching of the line optics can be envisaged at the beginning of the TT10 line. This is not possible at the end of the line where the optics must match the SPS optics at the injection point.

Status of the studies for the wire scanners in the PS (S. Gilardoni) (slides)

The analysis of the PS Booster and PS wires (composed of bundles of few wires with a diameter of about 10 um) by TS/MME has shown that the wires do not break as a result of the interaction with the beam but because of mechanical stress (report from TS/MME). The analysis of the wires has evidenced important differences in the diameters of the wires composing the bundle. No correlation has been found between the wire thickness and the probability of breaking the wire. Measurements have been performed with a fast camera to evidence possible wire oscillations. No vibration amplitude larger than 250 um has been detected (film - analysis).

Status of the LEIR commissioning (C. Carli) (slides)

There is still some disagreement between the intensity figures quoted by LINAC3 team and LEIR team. Need to be clarified. Action: C. Carli, M.Chanel.

It is not clear if the smaller longitudinal emittance measured in LEIR (need 0.025 eV.s) is an issue for LEIR or the PS. Action: C. Carli.

Latest results on LHC ion collimation (G. Bellodi) (slides)

Loss distribution at injection and collision optics (nominal) have been estimated for beam 1 and beam 2 at IR7. A higher collimation efficiency is observed for Beam 2. Skew collimator exhibit the highest load, the reason for that is not yet clear. J. Jowett suggested to study the tune dependence for these losses. For beam 2 a loss peak is observed at MQ19. The reason for that is not known.

All the simulations have been performed for a monochromatic lead ion beam. It is expected that the loss peaks should smear out if the momentum spread in the lead ion beam is added.

The proposal of increasing the sampling of the MAD optics every 10 cm everywhere (advanced during a Collimation Project missing) seems not to be justified. It was felt that a better interpolation of the loss point in the quadrupoles could be an advantage. Action: H. Braun.

Simulations of the collimation efficiency on the thickness of the primary collimators seem to indicate that the efficiency increases for short collimators. This should be further studied.

The study of the dependence of the loss maps on closed orbit distortion should be studied. This requires the modification of the ICOSIM programme to account for orbit errors. This is now is urgent. Action: H. Braun. 

High intensity H- charge exchange injection in the PSB at 160 MeV (M. Martini)

M. Martini mentioned that errors (dipolar or multipolar) can be introduced as kicks in ACCSYM.

M. Martini should specify the exact format required for the errors to be inserted in ACCSYM as soon as possible. Action: M. Martini.

C. Carli should provide a list of realistic errors for dipole and multipolar error for the PS Booster by the beginning of May. Action: C. Carli

Next meeting and tentative agenda

Monday, 15^th May 2006 at 09:00 in room 354-1-001

General information (G. Arduini)

PSB start-up status. (M. Chanel)

PS realignment (M. Martini)

PS start-up status. (S. Gilardoni)

Gamma jump in the PS: first results (S. Aumon)

Orbit error implementation in ICOSIM (H. Braun)