München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 21: Postersitzung

HK 21.82: Poster

Dienstag, 21. März 2006, 15:30–17:00, P

Development of a neutron time-of-flight source at the ELBE accelerator — •Joakim Klug¹, Eberhardt Altstadt¹, Carsten Beckert¹, Roland Beyer¹, Hartwig Freiesleben², Martin Greschner², Eckart Grosse^1,2, Arnd Junghans¹, Bärbel Naumann¹, Klaus Noack¹, Steffen Schneider¹, Klaus Seidel², Andreas Wagner¹, and Frank-Peter Weiß^1,2 — ¹Forschungszentrum Rossendorf, PF 510119, 01314 Dresden — ²Technische Universität Dresden, 01062 Dresden

The 5 ps pulses of the ELBE electron beam at Forschungszentrum Rossendorf, Dresden, with energies up to 40 MeV, can be used to produce a beam of intense neutron pulses in a liquid-lead radiator. The neutron energies range from 200 keV to 10 MeV, having an energy resolution of less than 1 % with a flight path of 3.9 m. In this energy interval, neutron cross section measurements are needed for fission, fusion, and transmutation. The neutron beam will be shaped by a 2.4 m long collimator made from borated polyethylene and lead, reducing the background of scattered neutrons and of photons at the sample position. Monte Carlo simulations with MCNP4C3 were performed to optimise the collimator composition. About 92 % of the neutrons at the experiment site retain their correct energy-to-ToF correlation. The neutron energy resolution is 0.4 % (FWHM) at the maximum intensity. For neutron-capture gamma rays, a BaF2 scintillation detector array of up to 60 crystals is being built, whereas for neutron detection, Li-glass scintillators and a 1 m2 plastic scintillator wall will be used.