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Abstracts Brochure - CERN

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TUPCH077<br />

TUPCH078<br />

TUPCH079<br />

27-Jun-06 16:00 - 18:00 TUPCH — Poster Session<br />

of relative velocity in particle collisions inside the beam. For this purpose, the transverse momentum distribution<br />

function is properly modified. Calculations performed for the VEPP-4M storage ring-collider show that the jump may<br />

depend significantly on the ratio between the vertical and radial beam emittance. We present results of our recent<br />

experiments on study of this dependence.<br />

Beam Phase Measurement in a 200 MeV Cyclotron<br />

J.L. Conradie, A.H. Botha, P.J. Celliers, J.H. Du Toit, D.T. Fourie, P.F.<br />

Rohwer, M.J. Van Niekerk (iThemba LABS)<br />

182<br />

New phase measuring equipment is being<br />

planned for the K 200 variable frequency,<br />

separated-sector cyclotron at iThemba LABS<br />

near Cape Town. A commercial lock-in am-<br />

plifier is used to measure the beam phase over the full radial range. Measurements are made at the third and fifth<br />

harmonics of the main RF frequency to limit pick-up from the flat-topping and main dees. Computer-generated<br />

signals, with phase and amplitude control, at the same harmonics, are used to cancel the signals coupled from the<br />

dees to the phase probes. In addition the signals without beam are vectorially subtracted from those with beam to<br />

enhance the sensitivity and accuracy. Results of measurements, using these techniques, on existing phase probes in<br />

the cyclotron, will be presented.<br />

BPM Design for the ALBA Synchrotron<br />

ALBA is a 3 GeV, low emittance, 3rd gen-<br />

F. Pérez, A. Olmos (ALBA) T.F. Günzel (ESRF)<br />

eration synchrotron light source that is in<br />

the construction phase in Cerdanyola, Spain.<br />

Vertical beam sizes down to a few microns will require beam stabilities on the submicron level. The BPM has to be<br />

designed in order to provide reliable and accurate beam position readings. Simulation and computational codes have<br />

been used to optimise, for a given vacuum chamber dimension, the BPM design. The optimisation has taken into<br />

account the usual sensitivity and intrinsic resolution parameters, but as well, the wakefield loss factor of the buttons.<br />

Due to the small vertical vacuum chamber dimension and the high design current, the beam power deposited in the<br />

buttons is becoming a concern due to the thermal deformation effects that can introduce errors at the submicron level.<br />

A compromise between a higher intrinsic resolution from one side, and a low power deposited by the beam in the<br />

buttons from the other, define the final buttons dimensions.<br />

Characterisation of the MAX-II Electron Beam<br />

Over the last year investigations of the MAX<br />

M. Sjöström, H. Tarawneh, E.J. Wallén (MAX-lab)<br />

II electron beam characteristics have been<br />

made. Examples of investigated parameters<br />

include the beam size, bunchlength, vacuum and Touschek lifetimes, and the machine functions. Since MAX II was<br />

commissioned in 1995 machine models have not been updated in a systematic fashion. As no realignment has been<br />

made and several new insertion devices have been installed, the situation necessitated characterisation of the electron<br />

beam in order to verify the validity of existing machine models.

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