Three-dimensional measurement of a proton beam profile at KOMAC with a scintillating fiber detector

The time structure of proton beam pulses has been measured using a three-dimensional beam profile monitor (BPM) with scintillating fibers at the Korea Multi-purpose Accelerator Complex (KOMAC). The BPM measured the spatial and temporal distributions of 100-μs-long macropulses at the 20-MeV and 100-MeV proton beamlines. The scintillating fiber BPM covers an effective area of 120(x)×120(y) mm2, with 12 fibers separated by 10 mm in each direction. Signals from 1-mm-diameter fibers were read out with a 1.3×1.3mm2 multi-pixel photon counter (MPPC) and fed into a 500-MHz flash ADC. We successfully measured the beam profile and its time structure at the same time. Using multi-layered collimators, the beam intensity could be sufficiently reduced so that the BPM could measure individual beam particles.