Synchrotrons and accumulators for high-intensity proton beams

Abstract

During the past five decades, the development of accelerator science and technology sustained exponential growth in the energy and intensity of proton beams. Combined with an increasing repetition rate, the use of high-powered proton beams has extended from nuclear and high-energy physics to modern applications, including spallation-neutron production, kaon factories, nuclear transmutation, neutrino-factory drivers, and, in future, energy amplification and muon-collider drivers. This paper surveys the design and operational experience of existing and proposed proton facilities, summarizes physical and engineering issues limiting the efficiency of high-intensity synchrotrons and accumulators, reviews beam-dynamics topics pertaining to high-intensity performance, and discusses future applications and outlook.

Conceptual design of the PEFP rapid cycling synchrotron

“…The PEFP RCS lattice has a four-fold symmetry. Although the low-order machine symmetry can give a dangerous low-order structure resonance, two or four symmetric lattice structure is usually accepted to ensure the space for other essential facilities [2]. The PEFP RCS has a four superperiodicity and a 20 pseudo-periodicity.…”

Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

“…Wei has surveyed the design and operational experience of existing and proposed proton facilities, and provides summaries of beam loss mechanisms [Wei03]. Beam losses are categorized into two classes: controlled and uncontrolled.…”

“…Wei has categorized uncontrolled beam loss as those losses linearly proportional to the beam's intensity (e.g., Coulomb scattering and nuclear scattering at injection foils, magnetic stripping, gas scattering, kicker malfunction, noises from rf systems and magnet power-supply systems), and those losses that grow progressively with intensity (e.g., space-charge-induced tune spread and coherent resonance crossing, instability, electron-cloud effects) [Wei03]. In the case of uncontrolled losses the magnitudes and locations of uncontrolled beam losses are difficult to know pre hoc.…”

Possibility of crystal extraction and collimation in the sub-GeV range

“…Application of crystal collimation to TeV range accelerators is currently studied with great interest. In the energy range on the order of 1 GeV, the spallation neutron sources are one example where an efficient halo collimation is required for the protons accumulated in a ring [25].…”

“…Upon first encounter with a crystal, particles were allowed to circulate in the ring and have further encounters with the crystal or aperture (in that case the particle was removed). The lattice of the SNS 1-GeV proton accumulation ring [25] (the linear transfer matrix was used with horizontal and vertical betatron tunes of x;y 5:82=5:80 and for the crystal position the horizontal betatron function of 10 m was selected) was selected as an example for simulation. The aperture limitation was imposed on the particle's angle at the crystal location: if its absolute value was greater than 0.5 (but less than 0.9) of the crystal bending angle, that particle was removed (considered lost at a collimator edge), so we counted only channeled particles that were steered at the proper angle.…”