Planned machine protection system for the facility for rare isotope beams at michigan state university

The Facility for Rare Isotope Beams (FRIB) at Michigan State University will utilize a high power, heavy-ion linear accelerator to produce rare isotopes in support of a rich program of fundamental research. The linac will consist of a room temperature-based front-end system producing beams of approximately 0.3MeV per nucleon. Three additional superconducting linac segments will produce beams of >200 MeV/u with a beam power of up to 400 kW. Therefore in the event of operating failures, it is extremely important to shut off the beam in a prompt manner to control the beam losses that may damage the accelerator components such as superconducting cavities. Another duty of the Machine Protection System (MPS) is to protect the accelerator against beam losses set by administrative limits to allow hands-on maintenance. FRIB has adapted the residual beam loss activation limit at 30 cm to be equivalent to 1W/m of operating beam losses. We are designing FRIB MPS to be flexible but redundant in safety to accommodate both commissioning and operations. A Machine Protection System protects the accelerator against failure and excessive beam losses; it is also dependent upon the operational mode of the accelerator and the beam dump in use. The operational mode is distributed via a finite state machine to all critical devices that have multiple hardware checkpoints and comparators. It is important to note that FRIB is a cw machine and MPS status is continuously being monitored by "device mode change" and real time data link. In case of a beam abort, the FRIB Machine Protection System will originate a stop-bit to all relevant data acquisition devices to dump the circular buffer data for post mortem analysis. In this paper, we present FRIB Machine Protection architecture, plans and implementation.