Neutron production in Pb/U assembly irradiated by 1.26 AGeV deuterons. First experimental results Ondřej Svoboda Neutron production in Pb/U assembly irradiated by 1.26 AGeV deuterons. First experimental results Ondřej Svoboda Dubna Work leader: RNDr. Vladimír Wagner CSc.

XVIII Baldin Seminar Main goals of the experiment Study of spallation reactions and the density of the neutron fluxes in large assembly from U and Pb Study of spallation reactions and the density of the neutron fluxes in large assembly from U and Pb Comparison between experimental results and simulations done in MCNPX, deducating results with respect to used models and libraries Comparison between experimental results and simulations done in MCNPX, deducating results with respect to used models and libraries Verification of the hi-energy neutron cross-section libraries Verification of the hi-energy neutron cross-section libraries Neutron balance and multiplication factor studies Neutron balance and multiplication factor studies

XVIII Baldin Seminar E+T setup Target – thick Pb rod (lenght 48 cm, diameter 8.4 cm) divided into 4 parts Target – thick Pb rod (lenght 48 cm, diameter 8.4 cm) divided into 4 parts Target was surrounded by natural uranium blanket in form of rods (totally kg) Target was surrounded by natural uranium blanket in form of rods (totally kg) Activation detectors – placed between the target parts, in front of and behind target + around the blanket Activation detectors – placed between the target parts, in front of and behind target + around the blanket Whole setup placed in wooden box, walls filled with polyethylen (biological shielding) Whole setup placed in wooden box, walls filled with polyethylen (biological shielding) On inner walls – Cd plate – shielding against thermal neutrons On inner walls – Cd plate – shielding against thermal neutrons

XVIII Baldin Seminar Deuteron experiment 30 November, 2005 on Nuclotron in LHE JINR Dubna, Russia 30 November, 2005 on Nuclotron in LHE JINR Dubna, Russia Incident particles: deuterons of energy 1.26 AGeV Incident particles: deuterons of energy 1.26 AGeV Total number counted by beam monitors: 6.5*10 12 deuterons Total number counted by beam monitors: 6.5*10 12 deuterons Irradiation time: 8 hours Irradiation time: 8 hours

XVIII Baldin SeminarBeam

XVIII Baldin Seminar Beam profile First - measured by Polaroid films First - measured by Polaroid films Then (during whole irradiation) – Cu monitor (just in front of target) Then (during whole irradiation) – Cu monitor (just in front of target)

XVIII Baldin Seminar Beam intensity Circle - Al monitor Circle - Al monitor Square – Al+Cu monitor Square – Al+Cu monitor 10 x 10 cm 2 10 x 10 cm 2

XVIII Baldin Seminar Beam monitors - reactions On Al beam monitors – reaction 27 Al(d,3p2n) 24 Na, only one cross-section value: ± 1.50 mbarn (2330 MeV) On Al beam monitors – reaction 27 Al(d,3p2n) 24 Na, only one cross-section value: ± 1.50 mbarn (2330 MeV) On Cu beam monitors – 58 Co, 56 Co, 55 Co, 52 Mn, 48 Cr, 48 Sc, 44 mSc, 57 Ni, 48 V, 43 K, 61 Cu isotopes, no cross-section data available!!! On Cu beam monitors – 58 Co, 56 Co, 55 Co, 52 Mn, 48 Cr, 48 Sc, 44 mSc, 57 Ni, 48 V, 43 K, 61 Cu isotopes, no cross-section data available!!! => for Cu beam monitors only relative comparison => for Cu beam monitors only relative comparison

XVIII Baldin Seminar Beam monitors - results Evaluation of the beam monitors had fundamental importance for whole experiment! total proton flux through Al monitor - 6.5(7)x10 12 beam shift: 0.3 cm down and 1.5 cm right elliptical shape close to circle

XVIII Baldin Seminar Detection of emitted neutrons (1) Neutrons coming from spallation reactions in target were measured by the method of neutron activation analysis Neutrons coming from spallation reactions in target were measured by the method of neutron activation analysis Used activation materials - Au, Al, Bi, Co, Y, In, Ta foils Used activation materials - Au, Al, Bi, Co, Y, In, Ta foils Foils properties: weight ~ 1 g, thickness ~ 0.1 mm (according to foil material), totally some 100 pieces Foils properties: weight ~ 1 g, thickness ~ 0.1 mm (according to foil material), totally some 100 pieces AlAuBiCoInTa

XVIII Baldin Seminar Reaction Treshold energy [MeV] Half-life 181 Ta (n,2n) 180 Ta h 181 Ta (n,3n) 179 Ta y 181 Ta (n,4n) 178 Ta min 181 Ta (n,5n) 177 Ta h 181 Ta (n,6n) 176 Ta h 181 Ta (n,7n) 175 Ta h 115 In (n,  ) 116m In 054 min 115 In (n,2n) 114m In d 115 In (n,3n) 113 In16.2stable 115 In (n,4n) 112 In min 115 In (n,5n) 111 In d 115 In (n,6n) 110 In h 115 In (n,7n) 109 In h Detection of emitted neutrons (2)

XVIII Baldin Seminar Measurement of activated foils Foils were measured on HPGe detectors Foils were measured on HPGe detectors Evaluation of the measured spectra was done in the Deimos32 program – it fits the gamma-peaks to Gauss curves Evaluation of the measured spectra was done in the Deimos32 program – it fits the gamma-peaks to Gauss curves Fitted peaks were assigned to the relevant isotopes Fitted peaks were assigned to the relevant isotopes Yields of produced isotopes have been computed with respect to all corrections (decay during the irradiation, coincidences, unequable irradiation, square emittors...) Yields of produced isotopes have been computed with respect to all corrections (decay during the irradiation, coincidences, unequable irradiation, square emittors...)

XVIII Baldin Seminar Longitudinal distributions of produced isotopes in Au and Al foils – 3 cm from the target axis 3 cm from the target axis

XVIII Baldin Seminar Radial distributions of produced isotopes in Au and Al foils – first gap

XVIII Baldin Seminar Radial distributions of produced isotopes in In foils – first gap

XVIII Baldin Seminar Conclusion Main aim of this experiment is a research of the neutron distribution in the setup, simulation of the setup in MCNPX and comparing of obtained results Main aim of this experiment is a research of the neutron distribution in the setup, simulation of the setup in MCNPX and comparing of obtained results At present we are finishing with the experimental part and we prepare simulations At present we are finishing with the experimental part and we prepare simulations Next experiment with deuterons – November 2006?? Next experiment with deuterons – November 2006?? Thank you for your attention…