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M. Lamont et al.
of powering equipment from overheating (magnets, power converters, high current
cables); the protection of superconducting magnets from damage after a quench;
and the safe operations of high power klystrons. Secondly there is the protection
of equipment from high stored beam energy. This is related to the high beam
power of high power proton accelerators such as ISIS, SNS and the PSI cyclotron,
to the emission of synchrotron light by electron/positron accelerators and to the
increase of energy stored in the beam (in particular for hadron colliders such
as TEVATRON, HERA and LHC). Effective protection in this case requires an
excellent understanding of accelerator physics and operation to anticipate the
failures that could lead to damage. It includes sophisticated beam and equipment
monitoring, a system to safely stop beam operation (e.g. dumping the beam) and
an interlock system providing the means to integrate the various systems. Machine
protection must be considered during design, construction and operation of the
accelerator.
9.9.1 Definition of Risk
The risk factor may be defined as the product of the probability of a failure
multiplied by the consequences of the failure (e.g. damage to equipment). The total
risk is the product of the individual risks factors of the possible failures in play.
Protection can be used to mitigate risk. In the accelerator domain it is clear that the
higher the risk factor, the more important that protection becomes.
The cost of given failure scenario can be estimated. The consequences may
be in terms of, for example: damage to equipment (repair requiring expenditure);
downtime of the accelerator; or the radiation dose to personnel accessing equipment;
or indeed a combination of the above.
The second factor entering into the risk is the probability that a given failure
happens. One can imagine that such an estimate be measured in number of failures
per year.
For operation with beam, a list of all possible failures that could lead to beam loss
into equipment should be considered. This is not obvious to establish since there are
a potentially large, but not innumerable, ways to lose the beam. However, the most
likely failure modes and, in particular, the worst case failures (in terms of cost) and
their probability must be considered.
9.9.2 Beam Losses and Consequences
Particle losses in a material lead to particle cascades. The maximum energy deposition can be deep in the material at the maxima of the hadronic and electromagnetic
showers. The energy deposition leads to a temperature increase and stress in the
M. Lamont et al.
of powering equipment from overheating (magnets, power converters, high current
cables); the protection of superconducting magnets from damage after a quench;
and the safe operations of high power klystrons. Secondly there is the protection
of equipment from high stored beam energy. This is related to the high beam
power of high power proton accelerators such as ISIS, SNS and the PSI cyclotron,
to the emission of synchrotron light by electron/positron accelerators and to the
increase of energy stored in the beam (in particular for hadron colliders such
as TEVATRON, HERA and LHC). Effective protection in this case requires an
excellent understanding of accelerator physics and operation to anticipate the
failures that could lead to damage. It includes sophisticated beam and equipment
monitoring, a system to safely stop beam operation (e.g. dumping the beam) and
an interlock system providing the means to integrate the various systems. Machine
protection must be considered during design, construction and operation of the
accelerator.
9.9.1 Definition of Risk
The risk factor may be defined as the product of the probability of a failure
multiplied by the consequences of the failure (e.g. damage to equipment). The total
risk is the product of the individual risks factors of the possible failures in play.
Protection can be used to mitigate risk. In the accelerator domain it is clear that the
higher the risk factor, the more important that protection becomes.
The cost of given failure scenario can be estimated. The consequences may
be in terms of, for example: damage to equipment (repair requiring expenditure);
downtime of the accelerator; or the radiation dose to personnel accessing equipment;
or indeed a combination of the above.
The second factor entering into the risk is the probability that a given failure
happens. One can imagine that such an estimate be measured in number of failures
per year.
For operation with beam, a list of all possible failures that could lead to beam loss
into equipment should be considered. This is not obvious to establish since there are
a potentially large, but not innumerable, ways to lose the beam. However, the most
likely failure modes and, in particular, the worst case failures (in terms of cost) and
their probability must be considered.
9.9.2 Beam Losses and Consequences
Particle losses in a material lead to particle cascades. The maximum energy deposition can be deep in the material at the maxima of the hadronic and electromagnetic
showers. The energy deposition leads to a temperature increase and stress in the