Minutes from Beamdynamics meeting

Javier is currently working on his thesis.

Warner said that he now can confirm the results of Wang for SEY. For some reason the results now agree both assuming a flat energy distribution and a half gaussian energy distribution for the secondary electrons. Warner also informed that the 3D code is now ready for testing.

-> Important to find out why the flat distribution did not give the same result before.

Peder is currently working on a realistic implementation of the emittance tuning bumps. This will be presented at a CLIC meeting in the beginning of December. An article should also be published on this topic. Daniel mentioned that the first results he showed in Valencia on this topic got some attention and it is necessary to publish this work as soon as possible.

-> Finish the bump article.

Erik is currently studying the power extraction efficiency. Simulations show that detuning of the PETS leads to less stability.

-> Erik should try to study this effect in more detail.

Andrea has converted the CTF3 lattice from MAD-X to Placet format. This turned out to be more difficult than first expected. A script for this kind of conversion already existed but new elements in the PTC version of MAD-X had to be treated as well. Andrea has also started studying the alignment of stage two of the bunch compressor using DFS and an energy difference obtained by BC stage one. Seems difficult...

Maxim informed that DFS of the BDS is difficult. A 1% energy difference has been used initially. The method he is currently using is slightly different from the one used in the main linac and should maybe me modified. Rogelio wondered about how the non-zero dispersion in the BDS is taken into account. The answer is that it can be treated in a similar fasion as for the curved main linac.

Rogelio is preparing his trip to Japan. He is currently looking at the ATF lattice. They have a problem with the DR and Rogelio will have a look at this. They also have a problem with the dynamic apertures.

-> Should try to learn how they carry out the alignment of the BDS.

Daniel finally said that he, apart from being at the Valencia meeting, recently has been studying the ILC wiggler (for positron production). He was given a file with the energy spread expected after the wiggler. The profile looked a bit funny and the beam wouldn't survive without correction. By using DFS things seem to work though. This method for producing the positron beam is cheaper and in case it works well it might also be an option for CLIC.

Daniel also mentioned that there will be a workshop on "Simulations of the collimation section" at CERN in the beginning of December. Report to Daniel in case you are interested in participating.

Next meeting will be held in two weeks. Erik might then have a Placet tutorial.