FRIB, East Lansing, Michigan, USA
Modern hadron accelerators create and transport beams that carry MW-scale power or store GJ-scale energy. The Machine Protection Systems (MPS) that guard against both catastrophic failures and long-term performance degradation must mitigate errant beam events on time scales as short as several microseconds. Measurement systems must also cope with detection over many orders of magnitude in beam intensity to adequately measure and respond beam halo loss. Other issues, such as radiated signal cross-talk, also confound and complicate delicate measurements. These requirements place enormous demands on the MPS beam diagnostics and beam loss monitors. We will review the current state of MPS diagnostic systems for this class of accelerator, including SNS, ESS, FRIB, LHC, J-PARC, and SPIRAL-II. Specific designs and key performance results will be presented and discussed.
ORNL, Oak Ridge, Tennessee, USA
The Target Imaging System (TIS) shows the size and position of the proton beam by using a luminescent Cr:Al2O3 coating on the SNS target. The proton beam hitting the coating creates light which is transferred through mirrors and optical fibers to a digital camera outside the high radiation area. The TIS is used during operations to verify that the beam is in the right location and does not exceed the maximum proton beam peak density. This paper describes our operational experience with the TIS and the results of studies on the linearity, uniformity, and luminescence decay of the coating. In the future, tubes with material samples might be placed in front of the target for irradiation studies. The simulations of placing tubes in the front of target coating and its effect on the beam width and position measurements are also discussed.
