The K1.8BR spectrometer system at J-PARC

TL;DR

The paper describes the design, construction, and performance of a new spectrometer system at J-PARC's K1.8BR beam line, aimed at studying antikaon-nucleon interactions and bound systems.

Contribution

It introduces a comprehensive spectrometer system combining beam line, target, cylindrical detector, and neutron counter for hypernuclear research at J-PARC.

Findings

Successful construction and operation of the spectrometer system.

High precision measurements of decay particles and neutron detection.

Enhanced capability for studying $ar K N$ interactions.

Abstract

A new spectrometer system was designed and constructed at the secondary beam line K1.8BR in the hadron hall of J-PARC to investigate $\bar K N$ interactions and $\bar K$-nuclear bound systems. The spectrometer consists of a high precision beam line spectrometer, a liquid $^3$He/$^4$He/D$_2$ 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 $\sim$15 m downstream from the target position. Details of the design, construction, and performance of the detector components are described.