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Neutron induced radiation damage in graphite: Preliminary Results

Neutron induced radiation damage in graphite: Preliminary Results A.Goffredi , M.Riccò, M.Belli, D.Pontiroli, T.Shiroka. Marrakech, 15/17-February-2007 Kenzi Farah Hôtel. Neutron induced radiation damage in graphite. Neutrons. Boron enriched Graphite.

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Neutron induced radiation damage in graphite: Preliminary Results

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  1. Neutron induced radiation damage in graphite: Preliminary Results A.Goffredi, M.Riccò, M.Belli, D.Pontiroli, T.Shiroka Marrakech, 15/17-February-2007 Kenzi Farah Hôtel

  2. Neutron induced radiation damage in graphite Neutrons Boron enriched Graphite Bulk Ferromagnetic Graphite LENA Reactor University of Pavia, Department of Nuclear Physics

  3. Boron insertion in Graphite Intercalation with Boron compounds Graphite-Boron Composite Real diffusion Simple mixing (possible molecule: NaBH4; no problem with secondary radioactive products)

  4. 135° C Tetraglyme 3 (NH4)SO4 + 6 NaBH4 2 + 3 Na2SO4 + 18 H2 Borazine Boron Intercalated Graphite • Borazine is called the Inorganic Benzene: good affinity; • Planar molecule even if there’s the N pairs. so • Promising intercalating molecule; • Optimizing intercalating conditions.

  5. n(x) = n0 exp (-x/λ) n(x) x Sample Preparation sample SRIM2003 Montecarlo Simulations Milling importance in producing the composite (grains dimensions!)

  6. Sample Preparation NaBH4 , Aldrich (99,99% purity grade) Graphite VSP-C --- RW-A Milled together for 3 min. (1 by 1) • Six samples: • VSP-C – NaBH4 1% • VSP-C – NaBH4 5% • VSP-C – NaBH4 10% • VSP-C (20 min.) – NaBH4 5% • RW-A – NaBH4 20% • RW-A – NaBH4 5% Five days irradiation --- 6 hours / day !!! With a φn (flux) = 1.7 · 10 12 n / cm2 sec

  7. Reactor Details

  8. SQUID Measurements Decrease of Diamagnetism after neutron irradiation

  9. SQUID Measurements Susceptibility measurements showing an unexpected temperature behaviour which is superimposed to the dominant diamagnetism of graphite and seems to be affected by oxigen exposure enlargement

  10. After Irradiation XRD RW-A Graphite New peaks corresponding to NaBF4 (Matched by a qualitative XRD analysis NaBH4 New Pellet container in Alluminium!!!

  11. Thanks for your attention!!

  12. 1.7 • relatively high flux • good B cross section • good number of events Reactor Details φn(flux) = 1.7· 10 12 n / cm2 sec P. Esquinazi Fluence: Фp = 2 nC / μm2 = 1.25 · 10 18 p+/cm2 Фp / φn = 7.3 ·10 5 sec ~ 1 week Normal time exposure Five days irradiation --- 6 hours / day !!! With a φn (flux) = 1.7· 10 12 n / cm2 sec

  13. SRIM2003 Montecarlo Simulations

  14. KAPTON Polyborazine KAPTON Boron Intercalated Kapton • Boron Chemical bonding: • Substitution on the aromatic rings; • Copolymer: PDMA/ODA // Poly-borazine. Film Sandwich

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