ABSTRACT
The neutron energy spectrum of the JRC 241Am-Li(alpha,n) radionuclide source has been measured at the PTB in Germany using various spectrometry systems, such as Bonner spheres, proton recoil counters and NE213 liquid scintillators. The source photon spectrum has been measured and the neutron contamination due to traces of beryllium through the 9Be(alpha,n)12C reaction has been determined. The effects associated with source encapsulation and the materials it contains have been investigated previously, using Monte Carlo simulations, the various structures seen in the spectra have been explained and the anisotropy of fluence distributions in 4pi have been calculated and compared to measurements. These extensive high resolution spectrometry measurements have been coupled to Monte Carlo calculations to provide a realistic spectrum and new spectrum-averaged fluence-to-dose equivalent conversion coefficients for the actual 241Am-Li source.
Subject(s)
Americium/analysis , Lithium/analysis , Neutrons , Radiation Protection/methods , Radiation Protection/standards , Radiometry/methods , Radiometry/standards , Body Burden , Calibration/standards , Computer Simulation , Computer-Aided Design , Equipment Failure Analysis/instrumentation , Equipment Failure Analysis/methods , Equipment Failure Analysis/standards , Germany , Internationality , Models, Statistical , Monte Carlo Method , Nuclear Reactors , Occupational Exposure/analysis , Photons , Radiation Dosage , Radiation Protection/instrumentation , Radioisotopes/analysis , Radiometry/instrumentation , Reference Standards , Relative Biological Effectiveness , Reproducibility of Results , Scattering, Radiation , Sensitivity and SpecificityABSTRACT
The new CANEL/T400 facility has been set-up at the Institute for Radiological Protection and Nuclear Safety (IRSN) to produce a realistic neutron field. The accurate characterisation of this neutron field is mandatory since this facility will be used as a reference neutron source. For this reason an international measuring campaign, involving four laboratories with extensive expertise in neutron metrology and spectrometry, was organised through a concerted EUROMET project. Measurements were performed with Bonner sphere (BS) systems to determine the energy distribution of the emitted neutrons over the whole energy range (from thermal energy up to a few MeV). Additional measurements were performed with proton recoil detectors to provide detailed information in the energy region above 90 keV. The results obtained by the four laboratories are in agreement with each other and are compared with a calculation performed with the MCNP4C Monte-Carlo code. As a conclusion of this exercise, a reliable characterisation of the CANEL/T400 neutron field is obtained.
