LAL ILC MDI/BDS/ATF2 group meeting

Thursday 14 Jun 2007, 11:00 → 13:00 Europe/Zurich

100 (LAL building 208)

Bi-monthly internal meeting to rewiew activities and exchange information in the LAL ILC MDI/BDS/ATF2 group

Energy spread in an ATF2 final focus simplified line - Marie Thorey To understand the ATF2 final focus line, a simplified line was made with only dipoles and the final doublet. The effect of energy spread on second order aberrations was theoretically studied and the chromaticity correction was calculated and applied using MAD8, adding SF1 et SD0 sextupoles. The same was done for the full ATF2 final focus line, including a computation of the optical bandwidth in the presence of higher order terms.

11:00 → 11:15 Energy spread in ATF2 final focus simplified line

Speaker: Ms Marie Thorey (LAL)

Slides thorey14_06.pdf thorey14_06.ppt

Energy spread in ATF2 final focus simplified line – Marie Thorey To understand the ATF2 final focus line, a simplified line made (with only dipole and final doublet) was created, the effect of energy spread on second order aberrations was theoretically studied, chromaticity correction was calculated and applied (adding SF1 et SD0) and matching using MAD8 compute to verify theoretical results and improvement . Same work was done with ATF2 final focus line and the optic bandwidth computed.

11:15 → 11:30 ATF2 line studies with BDSIM using two different beam inputs parameters

Speaker: Mr Hayg Guler (Ecole Polytechnique)

Slides Hayg_ATF2_Meeting_13.06.07.pdf Hayg_ATF2_Meeting_13.06.07.ppt

ATF2 line studies with BDSIM using two different beam input parameters - Hayg Guler Results of tracking with BDSIM in the ATF2 extraction and final focus lines were shown with two different input beams and with different options. With the internally provided Gaussian input with no correlations, no energy losses or secondary particles created were observed along the line. With an distributionproduced externally with appropriate correlations, secondary particle creation and energy loss do appear, but the rates are not yet really understood. In this presentation the way to compute Twiss parameters from particles distribution was also reminded. In the near future, more detailed comparisons of the beam sizes along the whole line and to the IP will be made between BDSIM and other tracking codes to check that the ATF2 optics is correctly translated from the MAD8 deck to the BDSIM setup.

11:30 → 11:45 First Parasitic Crossing Simulation in ILC Head-On Scheme

Speaker: Mr Thibault Derrien (LAL)

Slides ILC_meeting_14_juin_2007_new.pdf ILC_meeting_14_juin_2007_new.ppt

First Parasitic Crossing Simulation in ILC Head-On Scheme - Thibault Derrien One of the main technical challenges of the ILC head-on scheme is the design of the electrostatic separator. This element should minimize the electromagnetic perturbation induced by the outgoing bunch on the next incoming bunch at the first parasitic crossing, while providing enough separation between the beams at the location of the magnetic element further downstream. In order to estimate the minimal strength of this element a home-made "C + Shell" code has been written (using DIMAD and Guinea-Pig sofwtare). The enclosed presentation shows the results obtained for 20 consecutive collisions, based on 50 000 macroparticles per bunch and differents vertical jitters at the IP. In the near future, these results will be averaged and compared with similar averages without the electromagnetic perturbation, to define the minimum distance needed at the parasitic crossing.