Author/Authors :
Minami، نويسنده , , S. and Itabashi، نويسنده , , T. and Ajimura، نويسنده , , S. and Fukuda، نويسنده , , T. and Hayakawa، نويسنده , , H. and Hayakawa، نويسنده , , T. and Imoto، نويسنده , , W. and Kanie، نويسنده , , T. and Khanam، نويسنده , , F. and Kishimoto، نويسنده , , T. and Kohri، نويسنده , , William H. and Matsuoka، نويسنده , , K. and Mitoma، نويسنده , , Y. and Miyake، نويسنده , , Y.S. and Mori، نويسنده , , T. and Morikubo، نويسنده , , K. and Mura، نويسنده ,
Abstract :
We developed a trigger system for the measurement of proton-induced rare hadronic reactions around the beam kinetic energy T p = 400 MeV based on highly segmented trigger scintillation detectors and programmable logic modules. The trigger system was designed to enhance events with the negative-pion production by the difference of the curvatures of the particle tracks in a magnetic field. Since the production cross-section of the negative-pion by the proton-induced reactions was smaller by about 3 orders of magnitude than the total cross-section around the beam energy, we expected large reduction of the trigger rate by the negative-pion selection. The construction of the trigger system was not trivial due to a large detector acceptance that was inevitable to measure the rare reactions. The performance of the trigger system was evaluated by using T p = 430 MeV proton beams. An excellent reduction, more than 2 orders of magnitude reduction, of the background events was achieved.
