4SEASONS is a Fermi chopper spectrometer in operation at the Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC). 4SEASONS is expected to facilitate highefficiency measurements of weak inelastic signals on novel spin and lattice dynamics using thermal neutrons. The spectrometer is equipped with a coupled moderator and sophisticated components such as an elliptical converging neutron guide with high-critical-angle supermirrors, long (2.5 m) position-sensitive detectors, and a Fermi chopper appropriate for multiple-incident-energy (multi-E i) measurements by the repetition-rate multiplication technique. Herein, we discuss in detail the design and performance of the spectrometer, and present some examples of the measurements obtained using this spectrometer.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)