576
M. Lamont et al.
9.9.5 Strategy for Protection
The best protection strategy is to prevent by design the occurrence of a potential
failure. As an example, fast kicker magnets for diagnostics that could deflect the
beams into the vacuum chamber should only be installed in high intensity machines
if they are indispensable. If they are installed the available kick strength should be
below the level that can kick the beam to the aperture.
Failure should be detected as early as possible, with priority at the hardware level
of the system at the origin of the failure. If the failure detection is fast enough, beam
operation may be stopped before the beam parameters are affected in a significant
way. As an example, a failure of a magnet power converter should be detected as
early as possible within the converter itself.
When a failure is detected, beam operation must be stopped. For synchrotrons
and storage rings the beam is extracted by a fast kicker magnets into a beam dump
block. Injection must be inhibited.
Since detecting failures at the hardware level is not always possible or fast
enough, beam diagnostics is needed to detect abnormal beam behaviour. This
requires reliable, and sometimes dedicated, beam instrumentation.
9.9.6 Active and Passive Protection
Active protection is based on detection of a failure or of the consequences of the
failure on the beam. After detection the beam must be turned off and injection
inhibited, or, the case of a storage ring, the beam must be dumped as soon as
possible.
Passive protection there is a certain class of failures when active protection is
not possible. For example, protection against misfiring of an injection or extraction
kicker magnet might include a beam absorber or collimator to catch any mis-kicked
beam. All possible beam trajectories in such case must be considered, and the
absorber must be designed and positioned to absorb the beam energy without being
damaged itself.
9.9.7 Interlock Management
In large complex accelerator with high beam currents it is unavoidable that there will
be a high number of interlocks. In certain phases of operation (e.g. commissioning)
when operating with limited beam power, the disabling of certain interlocks is
certainly to be envisaged. However, it is vital to track any disable interlocks and
ensure that they are re-enabled when required. In the LHC the disabling of a selected
number of interlocks is possible for low intensity, low energy beams. When the beam
M. Lamont et al.
9.9.5 Strategy for Protection
The best protection strategy is to prevent by design the occurrence of a potential
failure. As an example, fast kicker magnets for diagnostics that could deflect the
beams into the vacuum chamber should only be installed in high intensity machines
if they are indispensable. If they are installed the available kick strength should be
below the level that can kick the beam to the aperture.
Failure should be detected as early as possible, with priority at the hardware level
of the system at the origin of the failure. If the failure detection is fast enough, beam
operation may be stopped before the beam parameters are affected in a significant
way. As an example, a failure of a magnet power converter should be detected as
early as possible within the converter itself.
When a failure is detected, beam operation must be stopped. For synchrotrons
and storage rings the beam is extracted by a fast kicker magnets into a beam dump
block. Injection must be inhibited.
Since detecting failures at the hardware level is not always possible or fast
enough, beam diagnostics is needed to detect abnormal beam behaviour. This
requires reliable, and sometimes dedicated, beam instrumentation.
9.9.6 Active and Passive Protection
Active protection is based on detection of a failure or of the consequences of the
failure on the beam. After detection the beam must be turned off and injection
inhibited, or, the case of a storage ring, the beam must be dumped as soon as
possible.
Passive protection there is a certain class of failures when active protection is
not possible. For example, protection against misfiring of an injection or extraction
kicker magnet might include a beam absorber or collimator to catch any mis-kicked
beam. All possible beam trajectories in such case must be considered, and the
absorber must be designed and positioned to absorb the beam energy without being
damaged itself.
9.9.7 Interlock Management
In large complex accelerator with high beam currents it is unavoidable that there will
be a high number of interlocks. In certain phases of operation (e.g. commissioning)
when operating with limited beam power, the disabling of certain interlocks is
certainly to be envisaged. However, it is vital to track any disable interlocks and
ensure that they are re-enabled when required. In the LHC the disabling of a selected
number of interlocks is possible for low intensity, low energy beams. When the beam