The K1.8BR spectrometer system at J-PARC

A new spectrometer system has been designed and constructed at the secondary beam line K1.8BR in the hadron hall of J-PARC to investigate K-bar N interactions and K-bar-nuclear bound systems. The spectrometer consists of a high precision beam line spectrometer, a liquid ³He/⁴He/D₂ target system, a cylindrical detector system that surrounds the target to detect the decay particles from the target region, and a neutron time-of-flight counter array located ∼15 m downstream of the target position. Details of the design, construction, and performance of the detector components are described. (author)