MEETING FOR BEAM EXTRACTION OPTICS (29/07/03)

Present: T. Fritioff, A. Jokinen, F. Wenander, I. Podadera

-         What it is important to get from the simulations, more than an optimization of the extraction system (very difficult), is a safety geometry to work. The optimization is due to be done during the off-line tests.

-         For that reason, it is important to be able to change the extraction electrodes easily. Above all, during the off-line tests since when the device will be already installed in the ISOLDE hall we don’t expect to make changes.

-         Fredrik remarks that it’s important to make tests of all the parts before the final installation.

-         In the design of the extraction electrodes must be taken in account the breakdown voltage (see the Paschen curve for Helium), and round all the elements to avoid discharges.

-         With the simulations that have been made the bunch size is of around 30 ms, more than the 20 ms got in Jväskylä.

-         The present simulated geometry seems to work well with the quadrupole designed by Tomas, but further improvements could be made. Fredrik propose to check the effect of increasing the length between the first electrode (59995 V) and the second electrode.

-         Also should be checked if it’s possible mechanically to construct the system. Tomas proposes to make the inner part of the electrodes changeable using  tapped holes.

Links to RFQ cooler and buncher meetings (NICE code required): http://ab-div-op-iso-rfqcb.web.cern.ch/ab-div-op-iso-rfqcb/meetings.htm

Links to RFQ cooler and buncher home page: http://ab-div-op-iso-rfqcb.web.cern.ch/ab-div-op-iso-rfqcb/