486
F. Bordry et al.
shielding (to have easy access to devices), heavy shielding (to provide radiationfree passage), robotic survey techniques and remote handling. All active components, like motors, and sensors must be compatible with high radiation
operation.
The use of modern programs is important for precise calculation of halo impact,
heat deposition, heat transfer, deformations, electro-magnetic fields and currents
[258–264]. The calculations must be used to verify the adequate performance of the
chosen design before construction starts as well as to optimize the performance of
operating system (see for example [265]).
8.8.3.3 Precision Actuation and Monitoring
The collimator is a mechanical system that (if movable) requires actuation and
monitoring. In dependence of the design chosen, one or several motors must
be used for moving the system. The motor of choice should be a stepping
motor with a resolver mounted to count the steps performed. The mechanical system translates the rotary into a lateral movement. The absolute position of jaws in the collimator tank can be determined in presence of a precise calibration with well-known mechanical stops. Similar is true for collimator
gaps.
The precise monitoring of jaw positions is often required for safety reasons.
In this case independent position sensors should in real-time monitor the jaw
positions. The measurements provide redundancy to the setting procedure that
relies on stepping motors and mechanical stops. The sensors also monitor positions when the jaws are away from the mechanical stops. The addition of orbit
measurements from in-jaw pickups [242] is complementary to mechanical jaw/gap
measurements.
Actuation and monitoring is more complicated for large accelerators where
issues of radiation resistance and signal transport over long cables arise. Specialized
solutions must be adapted [250, 266].
8.8.3.4 Examples of Installed Collimators
Two examples of recently constructed and installed collimators are shown in Fig.
8.89. The selected examples from SNS and LHC illustrate the strong differences
that are possible in collimator design, reflecting different requirements and boundary
conditions.
F. Bordry et al.
shielding (to have easy access to devices), heavy shielding (to provide radiationfree passage), robotic survey techniques and remote handling. All active components, like motors, and sensors must be compatible with high radiation
operation.
The use of modern programs is important for precise calculation of halo impact,
heat deposition, heat transfer, deformations, electro-magnetic fields and currents
[258–264]. The calculations must be used to verify the adequate performance of the
chosen design before construction starts as well as to optimize the performance of
operating system (see for example [265]).
8.8.3.3 Precision Actuation and Monitoring
The collimator is a mechanical system that (if movable) requires actuation and
monitoring. In dependence of the design chosen, one or several motors must
be used for moving the system. The motor of choice should be a stepping
motor with a resolver mounted to count the steps performed. The mechanical system translates the rotary into a lateral movement. The absolute position of jaws in the collimator tank can be determined in presence of a precise calibration with well-known mechanical stops. Similar is true for collimator
gaps.
The precise monitoring of jaw positions is often required for safety reasons.
In this case independent position sensors should in real-time monitor the jaw
positions. The measurements provide redundancy to the setting procedure that
relies on stepping motors and mechanical stops. The sensors also monitor positions when the jaws are away from the mechanical stops. The addition of orbit
measurements from in-jaw pickups [242] is complementary to mechanical jaw/gap
measurements.
Actuation and monitoring is more complicated for large accelerators where
issues of radiation resistance and signal transport over long cables arise. Specialized
solutions must be adapted [250, 266].
8.8.3.4 Examples of Installed Collimators
Two examples of recently constructed and installed collimators are shown in Fig.
8.89. The selected examples from SNS and LHC illustrate the strong differences
that are possible in collimator design, reflecting different requirements and boundary
conditions.