n_TOF spallation target upgrade Discussion with d’Huart Industrie 24 th September 2015 M. Calviani, A. Perillo-Marcone, S. Sgobba for the n_TOF target consolidation WG
Introduction 24 September 2015 MC/APM/SG - Discussion n_TOF/d'Huart2 n_TOF is a neutron time-of-flight facility for neutron cross-section measurements Neutrons are produced by impacting a high energy, high intensity proton beam on a pure lead cylinder block (99.995%), 60 cm diameter, 40 cm length (2x cores bought from d’Huart in 2008) The beam deposits ~5-10 kW in the bulk material target is water cooled, target core <120 °C and surface <80 °C to avoid water boiling Un-cladded design erosion/corrosion
New spallation target We have started the study for a new spallation target – one of the objectives would be to avoid direct contact between water and lead Reduction of circuit contamination Possibility to “contain” lead with a corrosion resistant refractory metal (i.e. tantalum) 24 September 2015 MC/APM/SG - Discussion n_TOF/d'Huart3
Solutions for a Ta-contained Pb target 1.Casting lead on a prepared Ta- container, performing CIPing (cold isostatic pressing) afterwards to improve contact 2.Casting lead on a prepared Ta-container, melting a second time (with a backing jacket?) inside a vacuum chamber in order to outgas and remove impurities 3.Shrink fitting of a Pb block inside a Ta- container 24 September 2015 MC/APM/SG - Discussion n_TOF/d'Huart4
Open questions 24 September 2015 MC/APM/SG - Discussion n_TOF/d'Huart5 Expected soundness/purity of the casting if melted in a Ta crucible compared to the usual D’Huart practice Before CIPing/remelting Following these operations Improvement in case of remelting? Inspectability (by UT)? Which resolution for imperfections? Which geometrical tolerances can be achieved on such a Pb cylinder? How would help the addition of antimony? Any experience in cooling lead parts with CO 2 ice (−78.5 °C) or liquid N 2 (- 200°C)?
Feedback Do you have any feedback on the feasibility of this solution? Can we envisage a small prototype? 24 September 2015 MC/APM/SG - Discussion n_TOF/d'Huart6
Thanks