A scintillating fiber detector for muon beam profile measurements in high magnetic fields

A position-sensitive detector (the Muon Beam Profile Monitor-μBPM) for non-relativistic muon beams and to be used in high magnetic fields was developed. The μBPM consists of a grid of 20 scintillating fibers probing the muon beam intensity along the horizontal (x) and the vertical (y) directions perpendicular to the beam direction (z), i.e., at xi and yj coordinates of the fibers (i,j=1…10). The readout of the fibers is realized by novel avalanche microchannel photodiodes (AMPDs). The use of AMPDs results in a compact design of the device, its insensitivity to magnetic fields, and the ability to handle high event rates. The μBPM was successfully utilized in the measurement of the muon beam profiles in magnetic fields up to 4.8 T.