Author/Authors :
Atchison، نويسنده , , F. and Baumann، نويسنده , , P. and Bry?، نويسنده , , T. and Daum، نويسنده , , M. and Egorov، نويسنده , , A. and Fierlinger، نويسنده , , P. and Fuchs، نويسنده , , P. and Henneck، نويسنده , , R. and Joray، نويسنده , , St. and Keil، نويسنده , , R. and Kirch، نويسنده , , K. and Krutova، نويسنده , , R. and Kühne، نويسنده , , G. and Lebedev، نويسنده , , V.T. and Obermeier، نويسنده , , H. and Orlova، نويسنده , , D.N. and Perret، نويسنده , , Ch. and Pichlmaier، نويسنده , , A. and Richard، نويسنده , , Ph. and Serebrov، نويسنده , , A. and Thies، نويسنده , , S.، نويسنده ,
Abstract :
We have examined the suitability of lead (Pb)/tin (Sn) alloys with atomic ratios between 4:1 and 12:1 for use as a spallation target material for the PSI spallation ultracold neutron source. The measured corrosion rate with distilled water, R c < 6 × 10 - 5 cm / year , is more than a factor of 80, less than for normal Pb; this corrosion rate is satisfactory. Microscopic investigations of the surface after the exposure to water revealed no visual changes. Small angle neutron scattering showed that the alloy is mechanically stable under thermal cycling. An experimental simulation of a water-cooled spallation neutron target made of Pb/Sn pebbles with a filling factor of 60% was investigated; the pulsed proton beam was simulated using hot and cold water in the target ‘cooling’ circuit. With realistic operational parameters for the cooling circuit, serious deformation of the PbSn pebbles occurred which finally blocked the cooling circuit. The Pb/Sn alloys solve the corrosion problem but its mechanical properties are inadequate leading to too short a lifetime to be practical in the PSI spallation source.
Keywords :
Spallation neutron sources , Neutron sources , Spallation neutron targets , Ultracold neutrons
