Accurate Neutron-nucleus Reaction Measurement Instrument ANNRI

Abstract

Accurate Neutron Nucleus Reaction Instrument (ANNRI) was designed for experiments using gamma-ray spectroscopy such as nuclear data, prompt gamma-ray analysis (PGA) and nuclear astrophysics. The instrument is equipped with two detectors that provide complementary information: Ge detectors, which offer higher energy resolution for gamma-rays, and NaI detectors, which allow us to use neutrons of higher energy. Other key components of the instrument, including double disk chopper, X stage collimator, filter unit, rotary collimator and auto sampler, are discussed. This paper gives an overview of recent results from experiments concerning nuclear data and PGA carried out using ANNRI. In the nuclear data research, we performed experiments of neutron-capture cross sections for long-lived fission products and minor actinides. In addition, we developed a new analytical technique that combines PGA and time-of-flight elemental analysis by using an intense pulsed neutron beam.