  A beam profile monitor (BPM) has been developed to measure photon beams at
the BM4 beamline of the Mikamine site, Research Center for Accelerator and
Radioisotope Science (RARIS-Mikamine; previously known as ELPH) at Tohoku
University. The BPM comprises plastic scintillation fibers and SiPMs, enabling
high-precision, real-time measurements of photon beams in the 1 GeV region.
Data acquisition utilized streaming TDC, a firmware commonly employed in the
J-PARC Hadron-hall, enabling real-time detection of high-intensity photon beams
with count rates reaching several tens of MHz. With sufficient statistical
data, the BPM achieved a 1 s beam-profiling accuracy of 10 {\mu}m. The proposed
BPM serves as a valuable resource for future physics experiments at the BM4
photon beamline and will contribute significantly to ongoing accelerator
research endeavors.
