High intensity chopper spectrometer 4SEASONS at J-PARC

Design and performance of a new chopper spectrometer 4SEASONS, which is under construction for the spallation neutron source at Japan Proton Accelerator Research Complex (J-PARC), are described. This spectrometer has middle energy resolution and two orders higher performance than current state-of-theart chopper spectrometers by utilizing a unique beam transport design and the repetition rate multiplication (RRM) method. 4SEASONS has a specification optimized for the study of the high critical temperature (T-c) superconductivity, and should be suitable for collecting weak inelastic signals from a single crystal over a wide four-dimensional (4D) Q-omega space.