Neutrons For Science: A neutron SPIRAL-2

Transcription

1 Neutrons For Science: A neutron SPIRAL-2 X. Ledoux and the NFS collaboration The SPIRAL-2 project NFS description and characteristics Buildings design Physics case

2 SPIRAL-2 deuterons 40MeV; 5mA graphite neutrons UCx

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4 Neutrons For Science NFS is one of the two facilities of the LINAG Experimental Area Use of the LINAG s beams to produce neutrons between 100keV and 40 MeV. NFS is composed of : - neutron beam - irradiation station - irradiation cell for interdisciplinary research at SPIRAL-2 The NFS collaboration : - 60 physicists from 19 laboratories - Letter of Intents submitted to the SAC of SPIRAL-2 - Open to new partners Scientific evaluation : Scientific Advisory Committee of SPIRAL 2 IN2P3 scientific council

5 Description Converter cave Beam line extension Magnet Beam stop Irradiation station (n, p, d) Time-of-flight area Beam at 0 Collimator beam quality Size (Lⅹl) (25m ⅹ 6m) - TOF measurements - free flight path Use of radioactive samples A< 1 GBq for thin layers A< 10 GBq for sealed sources I < 50 µa P < 2 kw

6 Neutron spectra provided at NFS Characteristics of the beams the LINAG : - 40 MeV deuteron and 33 MeV proton -I max = 5 ma - Pulsed beam F 0 = 88 MHz T=11 ns Burst width = 200 ps Continuous spectrum : E max = 40 MeV <E> = 14 MeV thick converter (1cm) Quasi-monokinetic beam : Thin converter (1-3 mm) E p = 3 33 MeV E n E p 2 MeV 7 Li(p,n) 7 Be Meulders et al., Phys. Med. Biol. (1975)vol 20 n 2, p235 Similar to IFMIF spectrum Schumacher et al.,nima421 (1999) p2843

7 Beam repetition rate Requirement: differentiation of 2 neutrons with the ToF t and t+t T LINAG = 11 ns T 1 μs T 6 μs Take only one burst over N (f = F 0 /N) - fast beam chopper -I = I max / N, with I max =5mA L(m) E th (MeV) T(μs) N I max (μa)

8 Energy resolution Δt : global resolution : 6% 5% 4% Detector Beam ΔE Δt 2 ΔL = ( + ) + 2 E t γ γ 1 L 1 ns scintillator 8 ns HPGe 1 ns Résolution en énergie L = 5m Dt= 1ns L = 20 m Dt = 1 ns L = 20 m Dt = 8 ns Unité arbitraire 0,008 0,007 0,006 0,005 0,004 0,003 0,002 0,001 0 Profils temporels sur la cible de NFS Δt= ( Δ ) 2 + ( Δ t ) 2 td b -0,8-0,3 0,2 0,7 Temps (ns) Deutons 40MeV, RMS = 0,199 ns Protons 33MeV, RMS = 0,164 ns ΔΕ/Ε (% 3% 2% L = 20 m & Δt = 1 ns ΔE/E < 2% 1% 0% Energie (MeV) L=20m & HPGe ΔE/E < 5%

9 Comparison with other neutron beam facilities 1,E+09 WNR 1,E+08 n-tof NFS 5 m 50 µa WNR : Los Alamos N-tof : CERN GELINA : Geel dn/dln(e) (n/cm 2 /s) 1,E+07 1,E+06 1,E+05 1,E+04 NFS 20 m 12 µa GELINA 1,E+03 E n : from 1 MeV to 40 MeV High flux small samples 1,E+02 0,01 0, Energie (MeV) coincident experiments Reduced γ flash Complementary to the existing facilities

10 Neutrons flux in the converter cave I=50 µa, D=7 cm Continuous spectra <E> = 14 MeV or Quasi-mono-energetic spectrum Φ (n/cm 2 /s/mev) Cross-section measurements by activation technique Irradiation of chips

11 CIRIS 2 Cellule d Irradiation pour la Recherche Interdisciplinaire sur Spiral 2 Irradiation Cell for Interdisciplinary Research at Spiral-2

12 Motivations and implantation Interests in SPIRAL2: Beams with high flux of light ions Dose up to 0.5 dpa/day Required beams: Materials for studies: Fe, Al, Cu, SiC, ZrO 2, steel Production of highly damage materials in reasonable times for parametric studies on nuclear fuel assembly Implantation of the cell: In front of NFS converter

13 Building design

14 Construction in 2 phases Milestone (J. M. Lagniel SPIRAL 2 Week January 2009) End of May 2009 : Building planning permission registration January 2010 : Beginning of the building construction January 2011 : Beginning of the process installation 29 th February 2012 : first beam

15 Simulations for facility design Performed by the CEA/IRFU/SENAC Safety issues (request for the preliminary safety file) Radioprotection Shielding design Nuclear waste production Activation Facility performance : Optimization and validation of the Building Prime Contractor proposals Evaluation of the neutron background in the TOF hall Iterations on several solutions Simulation tools : MCNPX Particle transport CINDER Evolution code

16 Calculations for safety issues Source (1) d+ Be and p+ 7 Li Source (4) 238 U sample Source (5) Interaction of the neutrons in the beam dump Evaluation of the Equivalent Dose Activation of the earth of material Concrete walls thickness Radioactive waste production

17 SPIRAL2 Phase 1 Building NFS Beam dump Injector area Q/A=1/3 free room for Q/A=1/6 S3 exp hall Superconducting LINAG To the production building Level -9,5 m

18 NFS facility Neutron beam dump Time-of-flight area Collimator Converter cave

19 Phase One construction Phase 1 ground level buildings from the selected Prime Contractor Phase 2

20 NFS

21 General Physics Case Reactions induced by fast neutrons are of first importance in the following topics : - Fission reactors of new generation - Fusion technology - Studies related to hybrid reactors (ADS) - Validation of codes - Nuclear medicine - Development and characterization of new detectors - Irradiation of chips and electronics structures used in space

22 Neutron induced fission NFS is well suited to the study of fission with fast neutrons - Fast spectra - High Flux small samples, coincidence measurements - Observables to be measured : - Fission fragments distributions - Prompt and delayed neutrons measurements - Energy dissipation by gamma ray emission Motivations : - Fundamental physic : improvement in fission process understanding - Applied physic to reactors - New generation - Residual heating - Delayed neutrons - Poisons modifying the reactivity

23 (n,x) cross section measurements (n,xn) reactions Maximum σ in the NFS energy range Neutron multiplication (n,lcp) Gazes and default production Energy deposition in therapy Composite particle prediction no model works Double differential measurements (n,xn), (n,lcp) Few data exist between 20 and 50 MeV Use of existing detection set-ups Techniques : In flight spectroscopy 4π neutron detector Scandal, Medley arrays..

24 Cross-section measurement needed for fusion technology W(n,nα+) 182m Hf Cross-section measurement by activation technique 2 irradiation stations : - Neutron induced reactions - Proton and deuteron I max limited to 50 μa - Power deposition on converter < 2 kw - Reduced activation «easy» sample manipulation IFMIF : International Fusion Material Irradiation Facility needs neutron and deuteron induced reactions cross-section for flux monitoring and activation evaluation. - Data scarce or not existing - Large discrepancies between data base Material to be studied for IFMIF : Al, Fe, Cr, Cu, Nb for cavities and beam transport elements Be, C, O, N, Na, K, S, Ca, Fe, Cr, Ni for Li loop σ, mb Cross Section, b p-d 2 O spectrum IEAF-2001 EAF-2005 d-li spectrum Neutron Energy, MeV Ditroy'00 93 Nb(d,2n) 93m Mo EAF Ditroi'00_Sig EAF20051_Nb93d2nMo92m Deuteron Energy, MeV

25 Letters of Intents for Day-One experiments at NFS Request from the Scientific Advisory Committee of SPIRAL-2 Comparison between activation and prompt spectroscopy as means of (n,xn) cross section measurements (IPHC Strasbourg) Study of pre-equilibrium process in (n,xn) reaction (CEA/DAM/DIF Bruyères-le-Châtel) Measurement of deuteron induced reaction cross-sections (NPI Rez, FZK Karlsruhe, NIPNE Bucharest) Anisotropiy and cross-section fission measurements at NFS (IPN Orsay, CEA/DSM/IRFU/SPhN, GANIL) Fission fragment distributions and neutron multiplicities (CNBG Bordeaux, CEA/DSM/IRFU/SPhN, GANIL, IPN Orsay, CEA/DAM/DIF Bruyères-le-Châtel)

26 Measurement of (n,n γ) et (n,xnγ) cross-sections Method: - Detection of the γ-rays stemming from the decay of excited states of nuclei created by the (n,xn) reaction. - Pulsed neutron beam - HPGe detectors IPHC Strasbourg 232 Th(n,5nγ) measured at Louvain-la-Neuve between 29 and 42 MeV Gamma detection HPGe planar detectors σ(n,5nγ) Counts * Th Thorium target Neutron beam Th(n,5n) σ(n,5nγ) σ(n,5nγ) Th Th Energy (kev) Energy (kev) 228 Th Energy (kev) Energy (kev)

27 Study of pre-equilibrium process in (n,xn) reaction Measurement of (n,xn) double differential cross section in coincidence with neutron multiplicity. Validation of pre-equilibrium models TALYS calculations 208 Pb E inc = 40 MeV Method : measurement of energy and angle of one neutron count of the (x-1) neutrons emitted simultaneously. Experimental set-up : NE213 detectors CARMEN detector Already existing and validated Beam request: Quasi-monkinetic beam Pulsed Well collimated

28 Anisotropy and cross-section fission measurements at NFS High precision measurement of anisotropies of fragment emission in neutron-induced fission of actinides Fission cross section measurement of very active actinides Fission fragment angular distribution is an ingredient in the measurement of the fission cross section Angular distribution gives information on the spin properties of fissionning nucleus The angular distributions are not well known above 10 MeV

29 Summary NFS will be a very powerful tool for physic with neutrons Technical issues : - White and quasi-monokinetic spectra in the 100 kev-40 MeV range - Neutron beam with high flux and good energy resolution - Complementary to the existing n-tof facilities - Adapted to radioactive samples - Cross-section measurements by activation techniques (n, p, d) - Material with light ions (CIRIS2) Physics case : - Fundamental and applied research - Fission and fusion technology - Material studies. First experiment in 2012

30 The NFS collaboration X. Ledoux, E. Bauge, G. Belier, T. Caillaud, A. Chatillon, T. Ethvignot, T. Granier, O. Landoas, J. Taïeb, B. Rossé, I. Thfoin, C. Varignon, CEA/DIF, Arpajon S. Andriamonje, D. Doré, F. Gunsing, D. Ridikas, CEA/DSM/IRFU/SPhN, Saclay, France V. Blideanu, CEA/DSM/IRFU/Senac, Saclay, France M. Aïche, G. Barreau, S. Czajkowski, B. Jurado, CENBG, Gradignan, France G. Ban, F. R. Lecolley, J. F. Lecolley, J. L. Lecouey, N. Marie, J. C. Steckmeyer, LPC, Caen, France P. Dessagne, M. Kerveno, G. Rudolf, IPHC, Strasbourg, France P. Bem, J. Mrazek, J. Novak, NPI, Řež, Czech Republic J. Blomgren, DNR, Uppsala, Sweden U. Fischer, S. P. Simakov, FZK, Karlsruhe, Germany B. Jacquot, F. Rejmund, GANIL, Caen, France L. Perrot, L. Tassan-Got, IPNO, Orsay, France M. Avrigeanu, V. Avrigeanu, C. Borcea, F. Negoita, M. Petrascu, NIPNE, Bucharest, Romania S. Oberstedt, A.J.M. Plompen, JRC/IRMM, Geel, Belgium O. Shcherbakov, PNPI, Gatchina, Russia M. Fallot, L. Giot, Subatech, Nantes, France A. G. Smith, I. Tsekhanovich, Department of Physics and Astronomy, University of Manchester, Manchester, UK O. Serot, J.C. Sublet, CEA/DEN, Cadarache, France E. Balanzat, S.Bouffard, S. Guillous, J. M. Ramillon, CIMAP, Caen, France A. Oberstedt, Örebro University, Örebro, Sweden