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- C. Fischer
CERN, Geneva, Switzerland
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Harmful heating mechanisms, resulting in wire breakage,
limit the utilisation of wire scanner monitors to below
a given beam intensity. This threshold depends on the
accelerator design parameters. In lepton colliders, the
short beam bunches generate strong wake-fields inside the
vacuum pipe which are sensed by the wire and are the
predominant current limit. These effects can be minimised
by a smooth design of the monitor cross section and by
choosing a wire made of an insulating material.
A second source of energy deposition inside the wire,
also present in hadron machines, and even when the wire
material is insulating, results from collision and ionisation
of the wire material atoms by the incident beam particles.
Calculations are presented to evaluate the efficiency of
this process and a possible solution is suggested which
may reduce this limitation. An example is given for the
case of the LHC.
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