Spectral Flux of the p-^7Li(C) Q-M Neutron Source Measured by Proton Recoil Telescope
Spectral Flux of the p-^7Li(C) Q-M Neutron Source Measured by Proton Recoil Telescope
J. Novak(Nuclear Physics Institute); P. Bem(Nuclear Physics Institute); M. Gotz(Nuclear Physics Institute); M. Honusek(Nuclear Physics Institute); E. Simeckova(Nuclear Physics Institute); M. Stefanik(Nuclear Physics Institute); U. Fischer(Institute for Neutron Physics and Reactor Technology); S. P. Simakov(Institute for Neutron Physics and Reactor Technology)
59권 23호, 1577~1580쪽
초록
The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p+^7Li(carbon backing) reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX. Simulated spectra were tested by absolute measurements using a proton-recoil telescope technique. The recoil-proton spectrometer consisted of a shielded scattering chamber with polyethylene and carbon radiators and the ΔE_1-ΔE_2-E telescope of silicon-surface detectors located to the neutron beam axis at 45˚ in the laboratory system. Si-detectors were handled by usual data acquisition system. Dead-time - and pulse-overlap losses of events were determined from the count rate of pulse generator registered during duty cycle of accelerator operation. The proton beam charge and data were taken in the list mode for later replay and analysis. The calculations for ^7Li(p,n) and ^(12)C(p,n) reactions reasonably reproduce CYRIC TOF neutron source spectra. The influence of neutron source set-up (proton beam dimensions, ^7Li-foil, carbon stopper, cooling medium, target support/chamber and the geometry-arrangement of irradiated sample) on the spectral flux is discussed in details.
Abstract
The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p+^7Li(carbon backing) reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX. Simulated spectra were tested by absolute measurements using a proton-recoil telescope technique. The recoil-proton spectrometer consisted of a shielded scattering chamber with polyethylene and carbon radiators and the ΔE_1-ΔE_2-E telescope of silicon-surface detectors located to the neutron beam axis at 45˚ in the laboratory system. Si-detectors were handled by usual data acquisition system. Dead-time - and pulse-overlap losses of events were determined from the count rate of pulse generator registered during duty cycle of accelerator operation. The proton beam charge and data were taken in the list mode for later replay and analysis. The calculations for ^7Li(p,n) and ^(12)C(p,n) reactions reasonably reproduce CYRIC TOF neutron source spectra. The influence of neutron source set-up (proton beam dimensions, ^7Li-foil, carbon stopper, cooling medium, target support/chamber and the geometry-arrangement of irradiated sample) on the spectral flux is discussed in details.
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- 한국물리학회
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- 물리학