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Neutrons For Science (NFS) at SPIRAL-2

Neutrons For Science (NFS) at SPIRAL-2. X. Ledoux and the NFS collaboration. ● The spiral 2 project ● Neutron production modes ● Design ● Beam characteristics ● Irradiation facility ● Physics case. graphite. UCx. deuterons. neutrons. 40MeV; 5mA. SPIRAL-2. Spiral-2 Layout.

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Neutrons For Science (NFS) at SPIRAL-2

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  1. Neutrons For Science (NFS) at SPIRAL-2 X. Ledoux and the NFS collaboration ● The spiral 2 project ● Neutron production modes ● Design ● Beam characteristics ● Irradiation facility ● Physics case Contact: xavier.ledoux@cea.fr

  2. graphite UCx deuterons neutrons 40MeV; 5mA SPIRAL-2 Contact: xavier.ledoux@cea.fr

  3. Spiral-2 Layout M. Jacquemet, GANIL Colloquium, Giens, june 2006 Contact: xavier.ledoux@cea.fr

  4. Beams delivered by the LINAG LINear Accelerator of Ganil ● Main specifications : 5 mA of 40 MeV deuterons 1 mA for heavy ions at Emax=14,5 A.MeV ● Two sources one for deuterons one for heavy ions ● Two RFQs q/A=3 q/A=6 for heavy ions (by now optional) ● LINAG F0 = 88 MHz T=11 ns 26 cavities Burst width = 200 ps Power at full intensity I=5mA, E=40 MeV P=200 kW Challenge: radioprotection 1015 n.s Converter composition All details available on www.ganil.fr Contact: xavier.ledoux@cea.fr

  5. Neutron For Science A working group was created to study : The possible use of the LINAG beam to built a neutron facility The Physics case realizable at NFS The facility will be composed of two parts : Neutron beam Irradiation station Means : Deuteron and proton beams Thin and thick converter Dedicated room(s) A letter of intents was presented to the Scientific Advisory Committee of SPIRAL 2 Contact: xavier.ledoux@cea.fr

  6. Neutron spectra provided at NFS (1) Deuteron break-up on Thick converter E deut = 40 MeV The deuteron are stopped in the converter (1cm) Continuous beam <E> = 14 MeV Be instead C converter allows to increase the flux by a factor of 2 Meulders et al., Phys. Med. Biol. (1975)vol 20 n°2, p235 ⇒Similar to IFMIF spectrum Contact: xavier.ledoux@cea.fr

  7. Neutron spectra provided at NFS (2) Neutron production by 7Li(p,n)7Be reaction Thin converter (1-3 mm) Quasi-monokinetic beam Ep = 3 – 33 MeV En≈ Ep –1,6 MeV 7Li(p,n)7Be Schumacher et al.,NIMA421 (1999) p2843 Contact: xavier.ledoux@cea.fr

  8. Detector(s) Sample Neutron For Science Facility • Experimental Hall • - Beam(s) at 0° and 30° optional • - Collimator design ↔ beam quality • Size (Lⅹl)≃(30m ⅹ 6m) • time-of-flight measurement • measurement at desired distance • large experimental set-up Converter cave - Beam line extension - Clearing magnet - Beam dump - Irradiation stations (n, p, d) Contact: xavier.ledoux@cea.fr

  9. T ≃ 1 ms T ≃ 6 ms T ≃ 1 ms T ≃ 6 ms Beam repetition rate Requirement: differentiation of 2 neutrons with the ToF tand t+T TLINAG = 11 ns Take only one burst over N (f=F0/N) - burst selector - I = Imax / N, with Imax=5mA Contact: xavier.ledoux@cea.fr

  10. Dt: Full time resolution: • Dtd≃1 ns scintillator • ≃8 ns HPGe • Dtb ≃1 ns Energy resolution The neutron energy is measured by time-of-flight technique L=30m and fast detector ⇒high resolution measurement HPGe detector ⇒DE/E < 5% for L=30 m Good resolution measurements require : - A unique burst selector - Burst duration on converter < 1ns (buncher might be needed) Contact: xavier.ledoux@cea.fr

  11. En: from 1 MeV to 40 MeV • High flux ⇒small samples • coincident experiments • Reduced g flash Comparison with other neutron beam facilities Spiral-2 : high intensity high resolution N-tof : CERN, Spallation,L=185 m,F=0.4Hz GELINA : Geel, Photofission, F=800Hz,30 m Complementary to the existing facilities Contact: xavier.ledoux@cea.fr

  12. Comparison with other neutron beam facilities ●Advantages of NFS : high average flux in the 1-40 MeV range : - small samples - coincident experiments production mode : - no high energy neutron (in comparison with spallation) - reduced gamma flash (in comparison with photoreaction) Hall size : - desired distance between 5 and 30 m high flux or high resolution - use of large set-up ●Disadvantages of NFS - high frequency - flux by burst smaller than n-tof or Gelina - only fast neutrons (1-40 MeV) Contact: xavier.ledoux@cea.fr

  13. Measurement by activation technique Two irradiation stations can be installed in the converter cave : • Neutron induced reaction • The sample is put very close of the converter • White source <E> = 14 MeV • F>5.1011n/s/cm2for Id=50 mA • Quasi-monoenergetic (Li converter on carbon back-up) - Proton and Deuteron induced reaction → Cross-section measurement : - Off-line activity measurement in a separate room - Detectors for flux monitoring Imax limited to 50 mA - Low power deposition on converter < 2 kW - Reduced activation « easy » sample manipulation Contact: xavier.ledoux@cea.fr

  14. Low energy deuteron beam (Ed < 4 MeV) The neutron flux depend on the power the target can sustain Monoenergetic neutrons beam Mono-energetic neutrons can be produced by the following reactions •d + d → n + 3He Q=3.27 MeV - En(0 deg) = 3.2 –7.2 MeV for Ed= 0 - 4 MeV - Gaseous or solid (TiD) targets •d + T → n + 4He Q=17.59 MeV - En(0 deg) = 14 –20 MeV for Ed= 0 - 3.7 MeV - only solid target (TiT) Contact: xavier.ledoux@cea.fr

  15. Radioprotection simulations Converter cave roof 1,5 m walls 2 m TOF room : wall thickness ≈ 50cm neutron beam dump at 0 degree Light concrete: less activation than in concrete loaded with iron Contact: xavier.ledoux@cea.fr

  16. Radioprotection Public area : D < 0,5 mSv/h Neutron dose calculation for 100 mA d + Be (1 cm) Code PHITS (V. Blideanu) Contact: xavier.ledoux@cea.fr

  17. Contact: xavier.ledoux@cea.fr

  18. Possible implementation Contact: xavier.ledoux@cea.fr

  19. 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 Workshop and reports: International Workshop on Neutrons for Science (NFS) at SPIRAL-2, GANIL, Caen, France; 13-14 December 2004. D. Ridikas et al, “Neutrons for Science (NfS) at SPIRAL-2”, Internal report DAPNIA report 05-30, Saclay, France (2005), A. Plompen, “Nuclear Data Needs for Nuclear Energy (fission) and Possible Contributions of SPIRAL2”, 15th Colloque GANIL, Giens, France (2006) U. Fischer, “Nuclear data needs for fusion technology and possible contribution by SPIRAL2”, 15th Colloque GANIL, Giens, France (2006). Contact: xavier.ledoux@cea.fr

  20. Neutron induced fission •Need of data for fast neutron essentially for minor actinides ADS, GEN IV reactors Cross-section measurements Neutron, gamma multiplicity and spectra Fragment yields • NFS short flight path → High flux Small samples (a emitters) Coincidence measurements • Complementary to surrogate reactions Limited to 10 MeV Model dependence • Study of the fission process Continuous spectrum →continuous excitation energy Coincidence experiment (A,Z) fragment distribution Contact: xavier.ledoux@cea.fr

  21. 56Fe(n,a) cross sections in several data bases. s (barns) Incident energy (MeV) (n,X) cross section measurements • (n,xn) reactions Maximum s in the NFS energy range Neutron multiplication • (n,LCP) Gazes and default production Energy deposition in therapy Composite particle prediction → no model works • In-beam g-ray spectroscopy White source and quasi-monokinetic spectrum (n,2n), (n,np), (n,a) reactions Use of large Ge array for g-g coincidence measurements • Double differential measurements (n,xn), (n,LCP) Few data exist between 20 and 50 MeV Use of existing detection set-ups Contact: xavier.ledoux@cea.fr

  22. Cross-section measurement needed for fusion technology •Cross-section measurement by activation technique •2 irradiation stations : - Neutron induced reactions - Proton and deuteron •Imax limited to 50 mA - Power deposition on converter < 2 kW - Reduced activation « easy » sample manipulation IFMIF and ITER need neutron and deuteron induced reactions cross-section. -Data scarce or not existing - Large discrepancies between data bases 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 Contact: xavier.ledoux@cea.fr

  23. Summary The LINAG characteristics are particularly well adapted to a neutron facility at SPIRAL-2 • White and quasi-monokinetic spectra in the 1-40 MeV range • Neutron beams with high flux and good energy resolution • - Complementary to the existing n-tof facilities • Irradiation stations for activation measurements (n, p, d) • Intensity on the converter limited to 50 mA • •reduced activation • •light converter design • NFS is somewhat independent of RIB production • Could start as soon as the LINAG is ready(2011) Contact: xavier.ledoux@cea.fr

  24. The NFS collaboration X. Ledoux1), M. Aïche2), G. Ban3), G. Barreau2), P. Baumann4), P. Bem5), V. Blideanu6), J. Blomgren7) , S. Czajkowski2), P. Dessagne4), E. Dupont6), T. Ethvignot1), U. Fischer8), F. Gunsing6), B. Jacquot9), B. Jurado2), M. Kerveno4), F. R. Lecolley3), J. L. Lecouey4), F. Negoita10), S. Oberstedt11), M. Petrascu10), A.J.M. Plompen11), F. Rejmund9), D. Ridikas6), G. Rudolf4), O. Shcherbakov12), S.P. Simakov8), J. Taïeb1) 1) Service de Physique Nucléaire, CEA/DIF, BP 12, 91980 Bruyères-le-Châtel Cedex, France 2) Centre d’Etudes Nucléaires de Bordeaux-Gradignan, 33175 Gradignan, France 3) Laboratoire de Physique Corpusculaire, ISMRa et Université de Caen, CNRS/IN2P3,France 4) Institut Pluridisciplinaire Henri Curien, Strasbourg, France 5) Nuclear Physics Institute, 25068 Řež, Czech Republic 6) Centre d’Etudes Nucléaires de Saclay, DSM/DAPNIA, France 7) Department of Neutron Research, Uppsala University, Uppsala, Sweden 8) Forschungszentrum Karlsruhe, Institute for Reactor Safety, Karlsruhe, Germany 9) GANIL, CEA/CNRS, Caen, France 10) NIPNE, Bucharest, Romania 11) Institute for Reference Materials and Measurements, Geel, Belgium 12) PNPI, Gatchina, Russia Contact: xavier.ledoux@cea.fr

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