|
abstract:
|
A Vac Ion pump is often used adjacent to the accelerator beamline. Stray magnetic fields are caused by the pump's permanent magnet. The pump is attached to the beamline in one of two configurations, either parallel or perpendicular to the beam path. Moving charged particles, along the beamline, experience a force or kick due to the stray B-field which de3flects the particles away from their original trajectory. From measurements made in each configuration, the deflection angles of the particles were calculated. For a particle of low energy, 4.5 MeV, the angles calculated were approximately 1 and 12 mrad for Config. 1 and Config. 2 respectively. The calculations for high energy, 20 MeV, yielded angles of 1/5 and 3 mrad. These deflections, for Config. 1, are lower than the inherent divergence of the beam, so this configuration can be used without compromising the beam quality. The deflection due to Config. 2, at low energy, is larger than the inherent beam divergence and at high energy, it is over half of the beam divergence angle. the second configuration should not be used.
|