Neutron multiplicity. Total radioactivity (Ci) Time after beam cut. Target A s 1min 1h 1d 1m 1y 10y 100y

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1 0 proton 000 MeV proton 500 MeV pronto 200 MeV Target A ' data and Mote Carlo simulations on spallation New relevant for the design of ADS reactions J.Benlliure University of Santiago de Compostela, Spain reactions constitute an optimum neutron Spallation for ADS source Intensity, energy and spatial distribution of the B neutron flux spallation B Residual nuclei produced in spallation reactions B Shielding to high-energy neutrons Radiotoxicity, activity and corrosion problems inside B target the Radiation damage and gas production in the target, B window and structural materials accelerator Neutron multiplicity beam: ma p(000 MeV) Target: Pb cylinder (20cm, 46cm) 0 3 Total radioactivity (Ci) s min h d m y 0y 00y Time after beam cut J.Benlliure USC Lahet calculations: D. Ridikas PhD, University of Caen 999

2 Aspects on interaction of relativistic protons with matter Spallation residue production Conclusion. ' General considerations: Spallation reactions High-energy nuclear data: Neutron production Outline Intermediate-energy nuclear data: Direct reactions J.Benlliure 2 USC

3 Quasi-free nucleon-nucleon collisions! Fast neutron and proton emission Thermal equilibration! Statistical emission of low energy nucleons and J.Benlliure 3 USC ' B Two-stage reaction: clusters Spallation reactions

4 B st interaction: Eß 800 MeV! 3 neut. + 2 prot. (E max ß 300 MeV), protons are stopped B 2 nd interaction: E» 300 MeV! direct reactions induced by neutrons (n,xn), (n,xlcp) J.Benlliure 4 USC Interaction of relativistic protons with matter Electromagnetic interaction: Range (cm) 60 protons in lead 50 st reaction nd reaction 0 E loss E * E loss Energy (MeV) Nuclear interaction: = 5 cm

5 Neutron production in spallation reactions Experiments at Saturne Pb(p,xn) "Demon" detectors (liquid scintillator) Low energy detectors (liquid scintillator) n Wire chambers p Scintillators double-differential cross sections: Beam Scintillator (Stop time of flight) Target Target (liquid H2) Rotation n 0 m Scale: 5 m full range in neutron energy detectors) (different full angular distributions of neutrons) (collimation F. Borne et al., Nucl. Instr. Methods A385 (997) 339 E. Martinez et al., Nucl. Instr. Methods A385 (997) 345 J.Benlliure 5 USC

6 J.Benlliure 6 USC Neutron production in spallation reactions Experiments at Saturne Pb(p,xn) Thin target Thick target 0 3 Pb(p,xn)X at E p = 200 MeV Pb (p,xn) E=.2 GeV D=20cm L=65cm Z=0cm d 2 σ/dωde (mbarn/mev/sr) ( 0 ) 0 ( 0 0 ) 25 ( 0 9 ) 40 ( 0 8 ) 55 ( 0 7 ) 70 ( 0 6 ) 85 ( 0 5 ) 00 ( 0 4 ) 5 ( 0 3 ) 30 ( 0 2 ) 45 ( 0) Neutrons/(incident proton.mev) Energy (MeV) Tierce: INC(Bertini) Tierce: INC(Cugnon) Neutron energy (MeV) X. Ledoux et al., Phys. Rev. Lett. 82 (999) 442

7 J.Benlliure 7 USC Neutron production in spallation reactions Experiments of the NESSI collaboration Pb,Hg,W(p,xn) Berlin Neutron Ball p + Pb p + Hg p + W Average neutron multiplicity per incident proton Target thickness (cm) E inc (GeV) 0 Pb W Hg 2.5 GeV.8 GeV.2 GeV 0.8 GeV 0.4 GeV Experiments at: GANIL (» 0.2 GeV) Coosy ( GeV) 0 Target thickness (0 23 atoms/cm 2 ) CERN (2-5 GeV) A. Letourneau et al., NIM B 70 (2000) 299

8 J.Benlliure 8 USC ' Residual nuclei production in spallation reactions direct kinematics: fl spectroscopy mass spectrometry identification after fi decay isobaric identification inverse kinematics: magnetic spectrometer: Bρ- E identification prior to fi decay isotopic identification recoil velocity

9 seetram target SC2 IC SC4 F2 IC2 F Pd 09 Pd A/Z ' Residual nuclei production in spallation reactions Experiments in inverse kinematics at GSI J.Benlliure 9 USC Nuclear charge

10 Centre d'etudes Nucl eaires, Bordeaux-Gradignan, France 56 Fe( A GeV)+p,d J.Benlliure 0 USC ' Collaboration: Experiments in inverse kinematics at GSI Gesellschaft für Schwerionenforschung, Germany Universidad de Santiago de Compostela, Spain Institut de Physique Nucl eaire d'orsay, France DAPNIA/SPhN, CEA/Saclay, France Experimental program: 238 U( A GeV)+Pb 97 Au(0.8 A GeV)+p 238 U( A GeV)+p,d 208 Pb(0.5- A GeV)+p,d

11 Residual nuclei production in spallation reactions Experiments in inverse kinematics at GSI 97 Au+p(800 A.MeV) Z > 0 mb > 3 mb >.4 mb >. mb >.08 mb N J.Benlliure USC

12 Residual nuclei production in spallation reactions Measured data in the reaction 208 Pb( A GeV) + p Lahet (Bertini+Dresner) INCL+ABLA Pb Tl Hg Z 208 Pb+p(000 A.MeV) > 0 mb > 3 mb >.4 mb >. mb >.08 mb Cross section (mb) Au 0 Pt Ir N 0 Os Re W Mass number A J.Benlliure 2 USC

13 identification after fi decay isobaric identification production in thin and thick targets University of Hannover ITEP Moscow ' Residual nuclei production in spallation reactions direct kinematics: fl spectroscopy full excitation functions for selected isotopes Main research programs: data: M.Gloris et al., NIM B 3 (996) 429 J.Benlliure 3 USC

14 dff dω dff J.Benlliure 4 USC Modeling spallation reactions Second stage: First stage: Statistical evaporation Intra-nuclear cascade n ß ρ(e Λ Sn ) p ρ(e Λ S p E c ) Removal of nucleons in quasi-free nucleonnucleon collisions Fission NN!NN NN!N dω n ß ρ(e Λ Sn ) f ρ(e Λ B f ) E B f Sn α Excitation energy: particle-hole excitations Description of the mass and charge distribution of fission residues

15 Modeling spallation reactions Evaporation residues: Fission residues: 0 INC(Liege)+ABLA(GSI) Lahet(Bertini+Dresner) Au Silberberg Tsao Os 0 INC(Liege)+ABLA(GSI) Lahet(Bertini+Dresner) Rh Silberberg Tsao Y Cross section (mb) Ta Yb Cross section (mb) As Co Neutron number Neutron number J.Benlliure 5 USC

16 Project HINDAS: Intermediate-energy nuclear data direct reactions: MeV Pb(n,xn), Pb(n,xnp), Pb(n,xlcp)... Pb(p,xn), Pb(p,xnp), Pb(p,xlcp)... Experiments at Louvain la Neuve: 30 < E p ;E n < 70 MeV Experiments at Uppsala: 25 < E p ;E n < 00 MeV Experiments at KVI: 20 < E p < 200 MeV J.Benlliure 6 USC

17 Inventory of the residual nuclei produced in the reaction Most of these programs are supported by the European Commission J.Benlliure 7 USC ' Conclusion Spallation reactions are an optimum neutron source for ADS Intensity, energy and spatial distributions of the produced neutrons Research programs are required in order to characterize spallation reactions for applications In Europe important efforts are in progress at different facilities: Saturne, GSI, Louvain la Neuve, KVI, Jülich, GANIL Uppsala, Theoretical description of these reactions can be improved with the new measurements