FRIB, East Lansing, Michigan, USA
Beam Loss Monitoring (BLM) System is an essential part to protect accelerator from machine faults. Compared with the empirical or uniform BLM arrangement in most accelerators, our new optimization approach proposes a “minimum spatial distribution” for BLM network. In this distribution, BLMs shall be placed at a small set of “critical positions” that can detect all failure / FPS trigger-able events of each fault mode. In additional, to implement a more advanced function of fault diagnosis, BLM should also be placed at “discrimination points” for fault-induced loss pattern recognition. With examples of FRIB failure event simulations, the author demonstrates the proof of concept to locate these “critical positions” and “discrimination points” for the minimum spatial distribution of BLMs.
FRIB, East Lansing, Michigan, USA
FRIB is using a charge stripper in folding segment 1 to increase the number of charge states of particles to enhance the acceleration efficiency. To control possible emittance growth after the charge stripper, the 3-dimensional on-stripper beam size should be as small as possible. The original 2-cavity-HWR (HWR stands for half wave resonator) rebuncher cryomodule is responsible for the longitudinal focusing before stripper. In order to accept and transport the beam downstream to linac segment 2, another kind of 3-cavity-QWR (QWR stands for quarter wave resonator) rebuncher cryomodule is baselined after the stripper. However, two kinds of cryomodules would increase the cost in design, therefore would be quite inefficient. In this paper, the FRIB lattice with only single-type 4-cavity-QWR rebuncher cryomodule in folding segment 1 is discussed. Positions of lattice elements are adjusted to accommodate the new type of cryomodule. Beam dynamics is optimized to meet the on-stripper beam requirement. The lattice is then adjusted and rematches.
FRIB, East Lansing, Michigan, USA
The FRIB driver linac is a front runner for the future high power hadron linacs, making a full use of CW, superconducting acceleration from very low β. Accelerator Driven Nuclear Waste Transmutation System (ADS), International Fusion Material Irradiation Facility (IFMIF), Project-X type proton accelerators for high energy physics and others may utilize the technologies developed for the design, construction, commissioning and power ramp up of the FRIB linac. Although each technology has been already well developed individually (except for charge stripper), their integration is another challenge. In addition, extremely high Bragg peak of uranium beams (several thousand times as high as that of proton beams) gives rise to one of the biggest challenges in many aspects. This report summarizes these challenges and their mitigations, emphasizing the commonly overlooked features.