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CENTRO ATOMICO BARILOCHE - ARGENTINA. 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.
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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
NyR - SOME RESEARCH ACTIVITIESTotal Cross Section Measurement and Calculation (subthermal to epithermal range) [+T]Neutron Diffraction [+T]Deep Inelastic Neutron Scattering [+T]Non Destructive Hydrogen Content DeterminationScattering Kernels for Hydrogeneous Materials CENTRO ATOMICO BARILOCHE - ARGENTINA
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
TOTAL CROSS SECTIONS Light water and plexiglass at room temperature ANGULAR DISTRIBUTIONS Experiment performed at the Orphee reactor (λ=0.7045 Ả)
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)
Multiple scattering corrections to the observed spectra (MARI experiment) Phys.Rev. B 58, 706 (1998)
SYNTHETIC SCATTERING KERNELS Phys.Rev. B31, 4167 (1985) CENTRO ATOMICO BARILOCHE - ARGENTINA
Cryogenic Moderators Cross sections calculated through ‘synthetic model’ compared with exp. data at different temperatures
Development of New Cold Neutron Moderators (Main objective of the ACoM collaboration) SCATTERING KERNELS FOR ADVANCED MODERATOR MATERIALS CENTRO ATOMICO BARILOCHE - ARGENTINA
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
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
Solid Methane: using SFS • Neutron spectra at different temps calculated with MCNP using SFS´based libraries.
Light Water Ice Cross Sections obtained from SFS
Clathrate Neutron X-sections and spectra calculated with the use of a Synth. Frequency Spectrum
Clathrate Clathrate, Methane and Ice at 20K
Cryogenic Moderators Cross sections calculated through ‘synthetic model’ compared with exp. data at different temperatures
Cryogenic Moderators Neutron spectra from moderator substances at different temperatures (calculated)
Calculated spectra of typical cryogenic moderators for the “Hokkaido Configuration”
SCATTERING KERNELS FOR ADVANCED MODERATOR MATERIALS Latest Development of New Cold Neutron Moderators CENTRO ATOMICO BARILOCHE - ARGENTINA
Neutron Scattering Kernel for Solid Methane in phase II Rolando Granada Centro Atomico Bariloche ARGENTINA CENTRO ATOMICO BARILOCHE - ARGENTINA
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
Carbon self Hydrogen self Interference caused by Proton spin correlations gГ = 1 for disordered molecules = 3 for ordered molecules CENTRO ATOMICO BARILOCHE - ARGENTINA
CH4 II Calculated components of σT(E) for CH4 II at 4K CENTRO ATOMICO BARILOCHE - ARGENTINA
CH4 II Comparison of calculated σT(E) with experimental data of Grieger et al. J.Chem.Phys.109,3161 (1998) CENTRO ATOMICO BARILOCHE - ARGENTINA
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
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
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
Low energy part of our adopted SFS CENTRO ATOMICO BARILOCHE - ARGENTINA
(Phase III) Experiments using the Bariloche LINAC CENTRO ATOMICO BARILOCHE - ARGENTINA
Experiments using the Bariloche LINAC CENTRO ATOMICO BARILOCHE - ARGENTINA
Calculated Spectra for the Methyl derivatives of Benzene CENTRO ATOMICO BARILOCHE - ARGENTINA
Comparison of Mesitylene and Mixture with standard moderators CENTRO ATOMICO BARILOCHE - ARGENTINA
Thank you! CENTRO ATOMICO BARILOCHE - ARGENTINA
Cryogenic Moderators 73 cm total height; 50 cm diameter; 38 cm moderator height. Stainless steel. Zircaloy-4 windows
Cryogenic Moderators Cryo-Moderator contained in succession of zircalloy-4 containers