The ELBE electron beam at Forschungszentrum Rossendorf, Dresden, with energies up to 40 MeV, will be used to produce intense neutron beams.The neutron radiator consists of a liquid * Speaker PoS(FNDA2006)015 PoS(FNDA2006)015 Development of a neutron ToF source at the ELBE accelerator J. Klug * Electron Linear accelerator with high Brilliance and low Emittance PoS(FNDA2006)015 PoS(FNDA2006)015 Development of a neutron ToF at the ELBE accelerator

The neutron time-of-flight (nToF) system at ELBE uses the electron beam to produce neutrons in a liquidlead neutron radiator. The neutron energies that can be used for nToF measurements range from 70 keV up to 10MeV when ELBE delivers a beam repetition rate of 0.5MHz. In this energy interval there is a need for neutron cross section data relevant for transmutation and for testing materials of fission and fusion reactors [1]. In addition, energies in the 30–70keV range, accessible with a reduced repetition rate, can be utilized for nuclear astrophysics experiments. By using the neutrons emitted from the radiator perpendicular to the direction of the electron beam a high suppression of the forward-peaked bremsstrahlung photons is obtained. The neutrons will be shaped by a collimator into a beam entering the experimental site in the adjacent room. Monte Carlo simulations were performed using MCNP4C3 [2] to characterize neutron and photon intensities at the sample position, time and energy distributions, and resolutions. The main parameters determining these are the radiator dimensions, the energy of the beam electrons, the beam current, and the length of the neutron flight path. Tab. 1 shows a compilation of predicted source strengths and fluxes at the measuring position 3.9m from the radiator, for different electron energies.