In 1967, Professor M. Kimura et al. generated pulse neutrons using 300 MeV Tohoku University Electron Linac and pioneered the TOF method neutron diffraction experiment in the world using Al powder sample. The accelerator driven neutron utilizations were later expanded into KENS and J-PARC in Japan, and became the cornerstone of neutron utilization alongside nuclear reactor neutrons globally. In this review a number of struggles, ingenuities, ideas of developing the new TOF method and the enthusiasms of founders, who were looking only at the glow of the white clouds of a single rose, will be introduced with the innovation of contemporary neutron science.

The first neutron source for neutron scattering experiments based on an accelerator was built at Laboratory for Nuclear Science (Present name is Research Center for Electron Photon Science) in Tohoku University. An electron linear accelerator was used for neutron generation. This facility was equipped with a thermal neutron source. Various kinds of instruments suitable to the pulsed neutron source were developed and pioneering works were performed. Later on, an electron linac facility in Hokkaido University was used for development of a cold neutron source and quasi-elastic scattering spectrometers. Knowledges and technologies accumulated in these facilities helped construction of KENS (National Laboratory for High Energy Physics (KEK) Neutron Source). KENS proved usefulness of a cold neutron source even at a pulsed neutron source and expanded applications in soft matter field as well as hard matter field. The ideas incubated during this process have been taken over to J-PARC/MLF.

Developments of neutron total scattering measurements at Tohoku LINAC opened the way for structural studies of disordered materials. It is remarkable that most technical fundamentals were established under the highly limited neutron flux.

Pulsed neutron scattering technique was started at the Nuclear Physics Laboratory (NPL) of Tohoku University 50 years ago. In this article, we overview the development of instruments from NPL, KENS, ISIS to J-PARC, which have been mainly used for studying highly correlated electron system. Deployment of the position sensitive detector is a most significant aspect to enhance the ability of instruments at pulsed neutron source. Also, chopper instruments have been a main contributor to the relevant scientific development.

First pulsed neutron beam was generated at Nuclear Science of Tohoku University using electron LINAC on 1968. Following 25 years, pioneering works for puled neutron science were reported in the research report of laboratory of nuclear science. We list all reported titles and overview the activities in this review.

We briefly introduce the pedigree of the backscattering neutron spectrometer and the specification of DNA; a time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), with Si crystal analyzers which was constructed at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC).

A compact accelerator-driven neutron source using proton beam has attracted attention in recent years. The mechanisms of this neutron emission, neutron emission target, accelerator and moderator are explained.

Neutron sources driven by electron accelerators have opened up the possibilities of pulsed-neutron beam experiments for material science. Neutrons are generated by a heavy metal-target with the pulsed electron beam. In the target, γ-rays of electromagnetic showers excite nuclei of the metal and fast neutrons are generated through the evaporation process. The fast neutrons are slowed down in a moderator, which is made of ambient water, polyethylene, or solid methane or mesitylene at about 20 K and pulsed thermal or cold neutron beam is extracted. Hokkaido University neutron source (HUNS) is one of the earliest electron accelerator driven neutron sources, that was used to develop various cold and thermal neutron sources and still actively used for material science.