ERINDA neutron sources for European users (first results and prospects)

Transcription

1 ERINDA neutron sources for European users (first results and prospects) Mart 26-27, 2011 Liblice, Czech Republic Vladimír Wagner E_mail: Co-ordination and Support Action 3 years ( ) Budget: M 15 partners Coordinate European efforts in neutron data studies Transnational access to neutron sources Scientific visits to ERINDA facilities Expert communication and dissemination of results

2 Nuclear facility very complicated system

3 High quality nuclear data are needed (mainly neutron reaction cross-sections)

4 Participated neutron sources AIFIRA 3.5 MV Van de Graaff accelerator 100 kev 6 MeV CENBG Bordeaux (France) BRR 10 MW research reactor cold and thermal IKI Budapest (Hungary) Lolita 3.7 MV Van de Graaff accelerator 10 kev 1.5 MeV FZ Karlsruhe (Germany) nelbe 40 MeV superconducting electron linac 20 kev 8 MeV, 14 MeV FZ Dresden (Germany) PIAF CV28 cyclotron and 3.7 MV Van de Graaff accelerator 24 kev 19 MeV PTB Braunschweig (Germany) TSL 180 MeV cyclotron 20 MeV 175 MeV UU-TSL Uppsala (Sweden) CEA 4 MV Van de Graaff accelerator, 7 MV tandem accelerator, 19 MeV electron linac 30 kev 20 MeV CEA Bruyéres-le-Chatel (France) n_tof 20 GeV proton beam of the PS + spallation neutron source 1 ev 250 MeV CERN Geneva (Switzerland/France) Tandem-ALTO 15 MV tandem + photo-fission source up to 20 MeV, IPN Orsay (France) (ALTO) up to 50 MeV

5 ERINDA FP7 Euroatom Framework Program Continuation of EFNUDAT project more efficient usage of neutron sources Transnational Access activities 2600h of additional beam time 26 typical experiments Pooling of resources Short Term Scientific visits (max 3 month) Support of 80 man weeks Program Advisory Committee decides on the proposed experiment and adequate facility.

6 Quasi-monoenergetic neutron sources Reactions of light projectiles (p,d) with not so heavy nuclei ( 3 H, 7 Li, 13 C ) Neutron sources based on 7 Li(p,n) 7 Be reaction NPI ASCR Řež Protons MeV Intensity 10 8 cm -2 s -1 Beam-line Graphite stopper Samples Advantage of two different source usage: Wide energy range and more accurate estimation of systematic uncertainties TSL Uppsala Li-target Protons MeV Intensity 10 5 cm -2 s -1

7 Neutron source nelbe (Rosendorf) Electron beam lead target bremsstrahlung radiation (γ,n) reaction Electron beam Neutron beam

8 e n neutron source absorber Liquid lead target, very high beam intensity Micro pulz length < 10 ps Base length for TOF m Neutron flux cm -2 s -1 Energy range 100 kev < En < 10 MeV Energy resolution E/E < 1 % (6 m) sample fission chamber γ n neutron detectors γ detectors

9 Spectrum of nelbe source in 2007 and 2009 Measurement rooms detectors for measurements of gamma photons and neutrons from reactions

10 GELINA TOF spectrometer (Belgium) Electron accelerator: energy 100 MeV, Pulse length 10 ns, repetition rate 800 Hz Features: 1) High beam intensity 2) Beam compression by magnet 3) Uranium target cooled by mercury 4) Very long base for TOF (up to 400 m) Average neutron flux: 3,4 x neutrons/s Together up to 12 experiments work Neutron flux: Energy resolution:

11 Spallation reactions as intensive source of neutrons Reaction of protons with high energies ( > 100 MeV ) with nuclei Very intensive source of neutrons it is possible obtain flux n/cm 2 s This condition is necessary for efective transmutation Three phases of spallation reaction: 1) Intranuclear cascade - incident proton kicks off in nucleon-nucleon collisions with nucleons with high energies 2) Preequilibrium emission escape of nucleons with higher energy from nucleus before thermal equilibrium restoration 3) Evaporation of neutrons or nucleus fission nucleus in thermal equilibrium unloads surplus energy by evaporation of neutrons with energy about 5 MeV. Neutrons are evaporated also by fission fragments High energy nucleons created during intranuclear cascade can produce further spallation reactions - hadron shower

12 Facility n-tof at CERN proton beam: E p = 20 GeV, Δt = 7 ns, I = protons, f = 0,8 Hz Lead target spallation reactions neutron beam: 300 n/p E n = 0,025 ev 1000 MeV distance 185 m, 10 5 n/pulse/energy order special collimation and moderation for different regime neutron beam FWHM = 11,8 mm Lead target - completion Shielding after target magnet

13 Spectrum of produced neutrons (simulation) (on the end of transport system -185 m from target) The n-tof energy resolution Moderator Target cooling system Experimentální hala u n_tof

14 Usage of reactor neutrons Mainly thermal and epithermal neutrons Possibility to use monochromator Possibility to obtain define energy by diffraction Measurement of fission reactions made by thermal neutrons Reactor LVR-15 of RC Řež Neutron reaction laboratory using Budapest reactor

15 Neutron chanel on LVR-15 reactor at Řež (rent by NPI) Beam size: 4 60 mm 2 Beam intensity: (1.5±0.2) 10 7 n cm -2 s -1 Gamma-gamma coincidence set-up Strength function measurements

16 Some examples of experiments A. Plompen (JRC-IRMM): 2 H(n,n) 2 H cross section at E n = MeV using the TOF method Eight Li-glass detectors 95% enriched in 6 Li 51 mm Ø x 12.7 mm thick Scionix, Netherlands 15 o Four detectors 165 o Four detectors 2 Assemblies swapped half way Ratio 15/165 by detector Data taking 9 June 16 July, 27 Sep 21 Oct (2011) Used facility nelbe Rosendorf forward backward Used CD 2 sample (AECL) % D 3 mm thick, 70 mm diameter

17 C. Domingo (U. Barcelona, Spain): Testing the UAB Extended Range Bonner Sphere Spectrometer for high energy neutrons. Extended BSS is able to cover 12 energy decades, from thermal to GeV Passive BSS: Gold activation foils 197 Au(n,p) 198 Au 99.99% purity 15 mm diameter 110 m thick 0.38 g mass Pb counts/channel Active BSS: 3 He proportional counter 3 He(n,p) 3 H R = Channel

18 Usage of PIAF facility (PTB Braunschweig): 1.2 and 14.8 MeV 1.2 MeV 14.8 MeV Usage of TSL neutron sources: 50, 100, 150 and 180 MeV

19 T. Belgya (IKI, Budapest, Hungary): Determination of the photon strength function in 114 Cd. Radiative neutron capture: neutron Other particle emitting reactions n, p,, f, Threshold reactions Target nucleus A Z X Compound nucleus A 1 * Z X Elastic scattering (n, n) Radiative capture (n, ) Always present There is always a competition between the reaction channels that depends on the nuclear structure thus the knowledge of radiative decay probability is important.

20 Experiments on 113 Cd (n, ) Budapest, used Budapest reactor (EFNUDAT experiment 2010) This resulted in about 1200 resolved gamma peaks The partial gamma-ray production cross-sections were determined New proposal for experiments using nelbe neutron source (ERINDA *E /Bn (b) % is missing E (kev)

21 X. Ledoux (CEA-DAM-DIF,Arpajon,France): Delayed neutron measurements for 237 Np neutron-induced fission. Previous experiment with Thorium 232 (EFNUDAT 2009) - Measurement of DN in Th- 232 neutron induced fission - Energies : 2, 3, 4, 6, 7, 10 and 16 MeV PTB Braunschweig Facility New proposal: to measure neptunium 237 Neutron detector : - Cylinder of CH 2 (Φint=6 cm, Φext=16 cm, L=37cm) - 12 tubes 3 He - efficiency ε > 20% (sample in centre) - constant efficiency between 0.1 and 1 MeV - not sensitive to gamma

22 Neptunium sample : Cylinder: Φ = 80 mm, thickness = 0.5 mm, m=50g - adapted handling procedure: 50 µsv/h at 100 cm Detector Beam line Production target

23 Neutron flux measurement Recoil proton telescope Proton recoil telescope (fluence measurement relative to n-p scattering)

24 A. Tsinganis (National Technical University of Athens, Greece): The Measurement of the fission cross-section of 240 Pu and 242 Pu at the CERN n_tof facility. An (n,f) measurement on 240,242 Pu is requested in the NEA Nuclear Data High Priority Request List 240 Pu 242 Pu 238 Pu % 238 Pu % 239 Pu % 239 Pu % 240 Pu % 240 Pu % 241 Pu % 241 Pu % Eight (8) samples (4 x 240 Pu, 4 x 242 Pu) received from IRMM (Geel) 3 cm diameter PuO 2 deposit 0.25 mm aluminum backing ( 5 cm diameter ) 242 Pu % 242 Pu % 244 Pu % 244 Pu % Mass 3.5mg Mass 3.0mg Activity 27.3MBq Activity 1.2MBq Surface density mg/cm 2

25 Mounting the samples Mounting carried out in ISOLDE lab under strict RP supervision Samples placed in appropriate holders for mounting MICRO-MEsh GAseous Structure Wireless gaseous detector

26 Detector test by means of uranium 235 measurement Data from U-235 sample 1 Amplitude distribution (1) Yield (2) Comparison with ENDF (3) 3 2

27 Example of short term visit Tudora (University Bucharest) Calculation of 234 U neutron induced cross-sections n+ 234 U cross-sect. calc. to provide the parameters of the fundamental fission barrier of 235 U (main CN) required to establish experimental conditions for isomeric shape studies (IRMM Geel Belgium) better contact with experimentalists U(n,f) JEFF (STATIS) Fission cross section (b) given in EXFOR as ratio to 235U, White 65 UKALD,, Lamphere 62 USAORL Fumitoshi 88 JPNTOH Lisowski 91 USALAS given in EXFOR as absolute data James 77 USAORL Lowry 54 USALAS Lamphere 53 USAORL Paradela 2006 IN2P3/IPN given in EXFOR as ratio to 235U Behrenz 77 USALRL Meadows 78 USAANL, Goverdovski 87 RUSFEI Kanda 86 JPNTOH Fursov 91 RUSFEI mainly fitted by JEFF En (MeV)

28 Conclusion ERINDA European project to make usage of neutron sources more efficient Important for measurements of crucial nuclear data (IV generation reactors, transmutation systems, fusion systems) Possibility for European users and scientists Last call for proposal deadline September 30, 2012 Czech neutron sources at Řež are also open for users