FRIB, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
In this paper, a unique low level radio frequency (LLRF) controller designed for a multi-harmonic buncher (MHB) is presented. Different than conventional designs, the single LLRF output contains three RF frequencies (f1, f2 = 2*f1, f3 = 3*f1) and is fed to a wide band amplifier driving the MHB. The challenge is while driving f1, due to the non-linearity of the amplifier, the f2 and f3 terms will also be generated and will couple into the control of these two modes. Hence an active cancellation algorithm is used to suppress the nonlinear effect of the amplifier. It is demonstrated in a test that the designed LLRF is able to control the amplitude and phase of the three modes in-dependently.
FRIB, East Lansing, Michigan, USA
Northern Illinois University, DeKalb, Illinois, USA
The reaccelerator facility (ReA) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) offers a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The original beam repetition rate at the ReA targets was the same as the LINAC RF frequency of 80.5 MHz. In order to add the capability to bunch at a lower frequency (desirable for many types of experiments using time of flight data acquisitions) a 16.1 MHz buncher has been designed, constructed, and commissioned. This paper reports the results of the commissioning of the device, and outlines some future avenues for further improvement of the properties of the bunched beam.
FRIB, East Lansing, USA
NSCL, East Lansing, Michigan, USA
The FRIB Machine Protection System (MPS) is designed to protect accelerator components from damage by the beam in case of operating failure. MPS includes master and slave nodes, which are controlled by MPS IOC. In this paper, we present design of MPS IOC and status of its prototyping.
FRIB, East Lansing, USA
The Facility for Rare Isotope Beams (FRIB), a high-power, heavy ion facility, can accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Its fast protection system is required to detect failure and remove beam within 35 μs to prevent damage to equipment. The fast protection system collects OK/NOK inputs from hundreds of devices, such as low level RF controllers, beam loss monitors, and beam current monitors, which are distributed over 200 m. The engineering challenge here is to design a distributed control system to collect status from these devices and send out the mitigation signals within 10 μS timing budget and also rearm for the next pulse for 100 Hz beam (10 mS). This paper describes an engineering solution with a master-slave structure adopted in FRIB. Details will be covered from system architecture to FPGA hardware platform design and from communication protocols to physical interface definition. The response time of ~9.6μS from OK/NOK inputs to mitigation outputs is reached when query method is used to poll the status. A new approach is outlined to use bi-direction loop structure for the slave chain and use streaming mode for data collection from slave to master, ~3μS response time are expected from this engineering optimization.