A design study of the proton storage ring for the Neutron Science Project at JAERI

Abstract

The goal of the proposed Neutron Science Project ( NSP ) at JAERI is to provide a short pulsed proton beam of less than 1µs with an average beam power of 5MW. To achieve such purpose, a proton storage ring operated at 50Hz with 4.17x10 14 protons per pulse at 1.5GeV is required. Two kinds of a lattice are examined as a lattice of the proton storage ring for neutron science project. One is FODO lattice and the other is Triple Bend Achromatic (TBA) lattice. This paper describes preliminary results of the lattice design for the proton storage ring.

Particle-core analysis of dispersion effects on beam halo formation

“…Although there exists some exceptions, such as laser-cooler rings and the small electron ring at the University of Maryland [7] where beam density can be extremely high, beam density in high-intensity rings now operating or under proposal is usually much lower than in high-intensity linacs. For example, in designing proton synchrotrons or storage rings for spallation neutron sources, tune depression, or ratio of depressed tune to undepressed one, is usually chosen to be sufficiently larger than 0.9 to reduce space charge effects [8,9]. This beam density is much lower than that in their injector linacs where tune depression is typically around 0.6.…”

A design study of the proton storage ring for the Neutron Science Project at JAERI

“…The lifetime of H 0 atoms depends on the Stark state in the magnet [3]. The lifetime of 1.5GeV H 0 atoms was calculated [2]. It was obvious from this calculation data that the H 0 atoms with n≤4 remain as H 0 and may be removed from the ring, and atoms with n>5 rapidly become H + and are accepted in the ring with the injection magnet whose strength of the magnetic field is 0.15T.…”

“…Each lattice has zero dispersion regions and long straight sections. The betatron variation around the ring of the FODO lattice is smooth [2]. Such a property will minimize the possible envelope oscillation for beams with large space charge tune shift.…”