Proposal for muon and white neutron sources at CSNS

Abstract

The China Spallation Neutron Source (CSNS) is a large scientific facility with the main purpose of serving multidisciplinary research on material characterization using neutron scattering techniques. The accelerator system is to provide a proton beam of 120 kW with a repetition rate of 25 Hz initially (CSNS-I), progressively upgradeable to 240 kW (CSNS-II) and 500 kW (CSNS-II'). In addition to serving as a driving source for the spallation target, the proton beam can be exploited for serving additional functions both in fundamental and applied research. The expanded scientific application based on pulsed muons and fast neutrons is especially attractive in the overall consideration of CSNS upgrade options. A second target station that houses a muon-generating target and a fast-neutron-generating target in tandem, intercepting and removing a small part of the proton beam for the spallation target, is proposed. The muon and white neutron sources are operated principally in parasitic mode, leaving the main part of the beam directed to the spallation target. However, it is also possible to deliver the proton beam to the second target station in a dedicated mode for some special applications. Within the dual target configuration, the thin muon target placed upstream of the fast-neutron target will consume only about 5% of the beam traversed; the majority of the beam is used for fast-neutron production. A proton beam with a beam power of about 60 kW, an energy of 1.6 GeV and a repetition rate of 12.5 Hz will make the muon source and the white neutron source very attractive to multidisciplinary researchers.

Recent progress in magnetic iron oxide–semiconductor composite nanomaterials as promising photocatalysts

“…The intrinsic high electrical conductivity of the carbon interlayer helps to transfer electrons. [105][106][107] For instance, Qi and co-workers first deposited a carbon interlayer on the surface of Fe 3 O 4 seeds by the hydrothermal reaction of glucose, and then deposited SnO 2 on the surface of Fe 3 O 4 /C, they successfully obtained Fe 3 O 4 /C/SnO 2 composite nanoparticles. 108 Shi and co-workers have prepared a core/multi-shell-structured Fe 3 O 4 / C/TiO 2 magnetic photocatalyst by the vapor phase hydrolysis process, and the photocatalytic abilities for degradation of methylene blue are studied.…”

Back-n white neutron facility at CSNS and first-year nuclear data measurements

“…The earlier studies show that the back-streaming neutrons along the impinging proton beam channel from the spallation target have properties of a wide energy spectrum, very high flux and good time structure, which is very suitable to be exploited as a white neutron source for nuclear data measurements and other applications [4][5][6][7][8][9]. With rapid development of nuclear energy in China, especially in advanced nuclear energy such as accelerator-driven subcritical systems (ADS), Thorium-based Molten Salt Reactor (TMSR) and fourth-generation reactors, very strong and eminent demands for much enhanced nuclear database have been increasing.…”

Conceptual design of MuSR spectrometer for EMuS using Monte Carlo simulation

“…CSNS also proposed to build a muon beamline to do MuSR experiments. The accelerator in CSNS can provide a high energy (1.6 GeV), high power (120 kW) proton beam with a repetition rate of 25 Hz [16,17]. Each pulse of the proton beam contains two bunches.…”