Irradiation effects in beryllium exposed to high energy protons of the NuMI neutrino source

JOURNAL OF NUCLEAR MATERIALS

卷:490

Article

Kuksenko, V.¹  Ammigan, K.²  Hartsell, B.²  Densham, C.³  Hurh, P.²  Roberts, S.¹ 

[1] Univ Oxford, Oxford, England

[2] Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA

[3] Rutherford Appleton Lab, Didcot, Oxon, England

关键词: Beryllium;    Proton irradiation;    Neutrino targets;    EBSD;    EDS;    Atom probe tomography;    Transmutation elements;    Precipitation;    Segregation;   

DOI  :  10.1016/j.jnucmat.2017.04.011

来源: Elsevier

【 摘 要 】

A beryllium primary vacuum-to-air beam 'window' of the Neutrinos at the Main Injector (NuMI) beamline at Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, USA, has been irradiated by 120 GeV protons over 7 years, with a maximum integrated fluence at the window centre of 2.06 10(22) p/cm(2) corresponding to a radiation damage level of 0.48 dpa. The proton beam is pulsed at 0.5 Hz leading to an instantaneous temperature rise of 40 degrees C per pulse. The window is cooled by natural convection and is estimated to operate at an average of around 50 degrees C. The microstructure of this irradiated material was investigated by SEM/EBSD and Atom Probe Tomography, and compared to that of unirradiated regions of the beam window and that of stock material of the same PF-60 grade. Microstructural investigations revealed a highly inhomogeneous distribution of impurity elements in both unirradiated and irradiated conditions. Impurities were mainly localised in precipitates, and as segregations at grain boundary and dislocation lines. Low levels of Fe, Cu, Ni, C and 0 were also found to be homogeneously distributed in the beryllium matrix. In the irradiated materials, up to 440 appm of Li, derived from transmutation of beryllium was homogeneously distributed in solution in the beryllium matrix. (C) 2017 Published by Elsevier B.V.

【 授权许可】

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