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CENTRO ATOMICO BARILOCHE - ARGENTINA

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  1. CENTRO ATOMICO BARILOCHE - ARGENTINA

  2. MODELING AND MEASUREMENTS OF NEUTRONIC PROPERTIES OF NEW CRYOGENIC NEUTRON MODERATORS J.R. Granada, F. Cantargi, S. Petriw, J. Dawidowski Centro Atómico Bariloche Comisión Nacional de Energía Atómica & CONICET ARGENTINA CENTRO ATOMICO BARILOCHE - ARGENTINA

  3. NyR - SOME RESEARCH ACTIVITIESTotal Cross Section Measurement and Calculation (subthermal to epithermal range) [+T]Neutron Diffraction [+T]Deep Inelastic Neutron Scattering [+T]Non Destructive Hydrogen Content DeterminationScattering Kernels for Hydrogeneous Materials CENTRO ATOMICO BARILOCHE - ARGENTINA

  4. Scattering Kernels for Hydrogeneous Materials Previous Related Experience: THE SYNTHETIC SCATTERING FUNCTION [J.R. Granada, Phys.Rev. B 31, 4167 (1985)] CENTRO ATOMICO BARILOCHE - ARGENTINA

  5. TOTAL CROSS SECTIONS Light water and plexiglass at room temperature ANGULAR DISTRIBUTIONS Experiment performed at the Orphee reactor (λ=0.7045 Ả)

  6. DIFFUSION PARAMETERS Pulse decay time for a traditional “Hokkaido configuration” DIFFUSION PARAMETERS Decay constant of heavy water at room temperature J.Nucl.Mat. 139, 158 (1986)

  7. Multiple scattering corrections to the observed spectra (MARI experiment) Phys.Rev. B 58, 706 (1998)

  8. CENTRO ATOMICO BARILOCHE - ARGENTINA

  9. SYNTHETIC SCATTERING KERNELS Phys.Rev. B31, 4167 (1985) CENTRO ATOMICO BARILOCHE - ARGENTINA

  10. CENTRO ATOMICO BARILOCHE - ARGENTINA

  11. Cryogenic Moderators Cross sections calculated through ‘synthetic model’ compared with exp. data at different temperatures

  12. Development of New Cold Neutron Moderators (Main objective of the ACoM collaboration) SCATTERING KERNELS FOR ADVANCED MODERATOR MATERIALS CENTRO ATOMICO BARILOCHE - ARGENTINA

  13. NJOY Calculations Synthetic Frequency Spectrum Combination of experimental and synthetic contributions Continuous part associated to traslational and rotational motions of the molecular system Vibrational modes (discretes) CENTRO ATOMICO BARILOCHE - ARGENTINA

  14. NJOY • (library ENDF) • s scattering • mass • Scattering proc • SFS Gaussian approx. S(Q,w) [SFS] 100 phonons LEAPR s(E) kernels [SFS] library ACE [SFS] integrals S(Q,w) [SFS] THERMR ACER

  15. Solid Methane: applications of the SFS concept

  16. Solid Methane: using SFS • Neutron spectra at different temps calculated with MCNP using SFS´based libraries.

  17. Light Water Ice Cross Sections obtained from SFS

  18. Clathrate Neutron X-sections and spectra calculated with the use of a Synth. Frequency Spectrum

  19. Clathrate Clathrate, Methane and Ice at 20K

  20. Cryogenic Moderators Cross sections calculated through ‘synthetic model’ compared with exp. data at different temperatures

  21. Cryogenic Moderators Neutron spectra from moderator substances at different temperatures (calculated)

  22. Calculated spectra of typical cryogenic moderators for the “Hokkaido Configuration”

  23. SCATTERING KERNELS FOR ADVANCED MODERATOR MATERIALS Latest Development of New Cold Neutron Moderators CENTRO ATOMICO BARILOCHE - ARGENTINA

  24. Neutron Scattering Kernel for Solid Methane in phase II Rolando Granada Centro Atomico Bariloche ARGENTINA CENTRO ATOMICO BARILOCHE - ARGENTINA

  25. CENTRO ATOMICO BARILOCHE - ARGENTINA

  26. The scattering law of a molecular system R lν(t) denotes the position of the atom v within the molecule l , can be written as the sum of inter (l  l´)- and intra (l  l´)- molecular contributions (also referred to as the outer and inner terms, respectively). The intermediate scattering function is CENTRO ATOMICO BARILOCHE - ARGENTINA

  27. Carbon self Hydrogen self Interference caused by Proton spin correlations gГ = 1 for disordered molecules = 3 for ordered molecules CENTRO ATOMICO BARILOCHE - ARGENTINA

  28. CH4 II Calculated components of σT(E) for CH4 II at 4K CENTRO ATOMICO BARILOCHE - ARGENTINA

  29. CH4 II Comparison of calculated σT(E) with experimental data of Grieger et al. J.Chem.Phys.109,3161 (1998) CENTRO ATOMICO BARILOCHE - ARGENTINA

  30. CH4 II Temperature dependence of σT at low energies caused by spin correlations Open circles: this work Closed circl.: Grieger exper. Lines: Ozaki calculations CENTRO ATOMICO BARILOCHE - ARGENTINA

  31. CENTRO ATOMICO BARILOCHE - ARGENTINA

  32. Neutron Cross Section Libraries for Aromatic Systems of interest as Cold Neutron Moderators F. Cantargi, J.R. Granada, L.A. Rodríguez Palomino, S. Petriw, M.M. Sbaffoni Centro Atomico Bariloche ARGENTINA CENTRO ATOMICO BARILOCHE - ARGENTINA

  33. MESITYLENE • Good moderator for a cold neutron source •  good resistance to radiation • (S.Kulikov, E. Shabalin, V. Melikhov, E. Kulagin, • Proceedings of the ICANS-XVI Meeting, Neuss, Germany, • 2003) •  high protonic density •  low-energy excitations • (I. Natkaniec, Proceedings of the ACoM6 Meeting, ESS-FZ • Julich, 2002) •  easy handling CENTRO ATOMICO BARILOCHE - ARGENTINA

  34. Low energy part of our adopted SFS CENTRO ATOMICO BARILOCHE - ARGENTINA

  35. (Phase III) Experiments using the Bariloche LINAC CENTRO ATOMICO BARILOCHE - ARGENTINA

  36. Experiments using the Bariloche LINAC CENTRO ATOMICO BARILOCHE - ARGENTINA

  37. Calculated Spectra for the Methyl derivatives of Benzene CENTRO ATOMICO BARILOCHE - ARGENTINA

  38. Comparison of Mesitylene and Mixture with standard moderators CENTRO ATOMICO BARILOCHE - ARGENTINA

  39. Thank you! CENTRO ATOMICO BARILOCHE - ARGENTINA

  40. CENTRO ATOMICO BARILOCHE - ARGENTINA

  41. 25 MeV e-LINAC

  42. 25 MeV e-LINAC

  43. Cryogenic Moderators 73 cm total height; 50 cm diameter; 38 cm moderator height. Stainless steel. Zircaloy-4 windows

  44. Cryogenic Moderators Cryo-Moderator contained in succession of zircalloy-4 containers

  45. CENTRO ATOMICO BARILOCHE - ARGENTINA

  46. CENTRO ATOMICO BARILOCHE - ARGENTINA