neutrons for science: a neutron facility @ spiral-2...wonder, 29th september 2009 contact:...

Contact: [email protected], 29th September 2009

Neutrons For Science: Neutrons For Science: A neutron facility @ SPIRALA neutron facility @ SPIRAL--22

X. Ledoux and the NFS collaboration

The SPIRAL-2 project

NFS description and characteristics

Buildings design

Physics case


SPIRAL-2

40MeV; 5mAdeuterons neutrons

graphite

UCx


Neutrons For Science

● The NFS collaboration :

- 60 physicists from 19 laboratories

- Letter of Intents submitted to the SAC of SPIRAL-2

- Open to new partners

● NFS is one of the two facilities of the LINAG Experimental Area

Scientific evaluation :Scientific Advisory Committee of SPIRAL 2 IN2P3 scientific council

● 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


Description

Time-of-flight area● Beam at 0°● Collimator ↔ beam quality● Size (Lⅹl) ≃ (25m ⅹ 6m)

- TOF measurements- free flight path

Converter cave ● Beam line extension● Magnet● Beam stop● Irradiation station (n, p, d)

I < 50 µA P < 2 kW

Use of radioactive samplesA< 1 GBq for thin layersA< 10 GBq for sealed sources


Neutron spectra provided at NFS

Continuous spectrum :Emax = 40 MeV<E> = 14 MeVthick converter (1cm)

Meulders et al., Phys. Med. Biol. (1975)vol 20 n°2, p235

⇒ Similar to IFMIF spectrum

Characteristics of the beams the LINAG :- 40 MeV deuteron and 33 MeV proton- Imax = 5 mA- Pulsed beam F0 = 88 MHz T=11 ns Burst width = 200 ps

Quasi-monokinetic beam :Thin converter (1-3 mm)Ep = 3 – 33 MeVEn ≈ Ep –2 MeV

Schumacher et al.,NIMA421 (1999) p2843

7Li(p,n)7Be


Beam repetition rate

Requirement: differentiation of 2 neutrons with the ToF t and t+T

L(m) Eth (MeV) T(μs) N Imax(μA)

5 0.1 1

0.1

50

30

100

6006 8

T ≃ 1 μs

T ≃ 6 μs

TLINAG = 11 ns

Take only one burst over N (f = F0/N)- fast beam chopper - I = Imax / N, with Imax=5mA


Energy resolution

L = 20 m & Δt = 1 ns ⇒ ΔE/E < 2%

L=20m & HPGe ⇒ ΔE/E < 5%

Δt : global resolution : Detector ≃ 1 ns scintillator

≃ 8 ns HPGe Beam ≃ 1 ns

( )Δ Δ ΔEE

tt

LL

= + ⎛⎝⎜

⎞⎠⎟

+ ⎛⎝⎜

⎞⎠⎟

γ γ 12 2

( ) ( )22bd ttt Δ+Δ=Δ

Profils temporels sur la cible de NFS

0

0,001

0,002

0,003

0,004

0,005

0,006

0,007

0,008

-0,8 -0,3 0,2 0,7

Temps (ns)U

nité

arb

itrai

re

Deutons 40MeV ,RMS = 0,199 ns

Protons 33MeV ,RMS = 0,164 ns

Résolution en énergie

0%

1%

2%

3%

4%

5%

6%

0 10 20 30 40

Energie (MeV)

ΔΕ

/Ε (

%

L = 5m Dt= 1ns L = 20 m Dt = 1 ns L = 20 m Dt = 8 ns


Comparison with other neutron beam facilities

Complementary to the existing facilities

• En: from 1 MeV to 40 MeV• High flux ⇒ small samples

coincident experiments• Reduced γ flash

1,E+02

1,E+03

1,E+04

1,E+05

1,E+06

1,E+07

1,E+08

1,E+09

0,01 0,1 1 10 100

Energie (MeV)

dN/d

ln(E

) (n/

cm2 /s)

WNRn-tofNFS 5 m 50 µANFS 20 m 12 µAGELINA

WNR : Los Alamos

N-tof : CERN

GELINA : Geel


Neutrons flux in the converter cave

● Continuous spectra <E> = 14 MeV

or

● Quasi-mono-energetic spectrum

→ Cross-section measurements by activation technique

→ Irradiation of chips

Φ(n

/cm

2 /s/M

eV)

I=50 µA, D=7 cm


CIRIS2

Cellule d’Irradiation pour la Recherche Interdisciplinaire sur

Spiral 2

Irradiation Cell for Interdisciplinary Research at Spiral-2


Motivations and implantation

• Implantation of the cell: In front of NFS converter

• Interests in SPIRAL2: – Beams with high flux of light ions– Dose up to 0.5 dpa/day

• Required beams:– Deuteron @40MeV-50µA– Helium @40MeV-100µA– Carbon @168MeV-47µA

• Materials for studies:– Fe, Al, Cu, SiC, ZrO2, steel

Production of highly damage materials in reasonable times for parametric studies on nuclear fuel assembly


Building design


Construction in 2 phases

Milestone (J. M. Lagniel SPIRAL 2 Week 26-30 January 2009)

End of May 2009 : Building planning permission registrationJanuary 2010 : Beginning of the building constructionJanuary 2011 : Beginning of the process installation

29th February 2012 : first beam


Simulations for facility design

Performed by the CEA/IRFU/SENAC

● Safety issues (request for the preliminary safety file)Radioprotection → Shielding designNuclear waste production → Activation

● Facility performance :Optimization and validation of the Building Prime Contractor proposalsEvaluation of the neutron background in the TOF hallIterations on several solutions

● Simulation tools :MCNPX Particle transportCINDER Evolution code


Calculations for safety issues

Source (1)Source (4)

Source (5)238U sample Interaction of the neutrons

in the beam dumpd+ Be and p+7Li

Evaluation of the Equivalent Dose → Concrete walls thicknessActivation of the earth of material → Radioactive waste production


SPIRAL2 Phase 1 Building

SuperconductingLINAG

NFS

Level -9,5 m

S3 exp hall

Injector area Q/A=1/3free room for Q/A=1/6

To the productionbuilding

Beamdump


NFS facility

Time-of-flight areaConverter cave

Collimator

Neutron beam dump


Phase One construction

Phase 1 ground level buildings from the selected Prime Contractor

Phase 2


NFS


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


● 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

Neutron induced fission


(n,X) cross section measurements

• (n,xn) reactionsMaximum σ in the NFS energy rangeNeutron multiplication

• (n,LCP)Gazes and default productionEnergy deposition in therapyComposite particle prediction → no model works

• Double differential measurements (n,xn), (n,LCP)Few data exist between 20 and 50 MeVUse of existing detection set-ups

• Techniques :In flight spectroscopy4π neutron detectorScandal, Medley arrays…..


Cross-section measurement needed for fusion technology

0 10 20 30 40 5010-2

10-1

100

101

102

103

EAF-2005

p-D2O spectrum

d-Li spectrum

IEAF-2001

186W(n,nα+)182mHf

σ, m

b

Neutron Energy, MeV

0 5 10 15 20 25 30 35 40 4510-3

10-2

10-1

100

Ditroi'00_Sig EAF20051_Nb93d2nMo92m

93Nb(d,2n)93mMo

Cro

ss S

ectio

n,

b

Deuteron Energy, MeV

EAF-2005.1

Ditroy'00

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

• Cross-section measurement by activation technique• 2 irradiation stations :

- Neutron induced reactions- Proton and deuteron

• Imax limited to 50 μA- Power deposition on converter < 2 kW- Reduced activation « easy » sample manipulation


● 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)

Letters of Intents for Day-One experiments at NFS

Request from the Scientific Advisory Committee of SPIRAL-2


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

228Th232Th(n,5n)0+

2+

4+

6+

8+

0

57.7

59

57.759

186.823

378.171

622.2

129.

065

191.3

4924

4.3

σ(n,5nγ)

σ(n,5nγ)

σ(n,5nγ)

Energy (keV)

228Th 4+ 2+

Energy (keV)

228Th 6+ 4+

Energy (keV)

228Th

8+ 6+

Energy (keV)

Co

un

ts

120 140 160 180 200 220 240 260 280 3000

200

400

600

800

1000

1200

* 102

232Th(n,5nγ) measured at Louvain-la-Neuve between 29 and 42 MeV

Thorium target

IPHC Strasbourg

HPGe planar detectors

Neutron beam

Gamma detection


Experimental set-up :NE213 detectorsCARMEN detectorAlready existing and validated

Method :

• measurement of energy and angle of one neutron

• count of the (x-1) neutrons emitted simultaneously.

Study of pre-equilibrium process in (n,xn) reactionMeasurement of (n,xn) double differential cross section in coincidence with neutron multiplicity.

TALYS calculations

208PbEinc = 40 MeV

Validation of pre-equilibrium models

Beam request:Quasi-monkinetic beamPulsedWell collimated


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


Summary

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)

NFS will be a very powerful tool for physic with neutrons

First experiment in 2012

Physics case :

- Fundamental and applied research

- Fission and fusion technology- Material studies ….


The NFS collaborationThe 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, ArpajonS. Andriamonje, D. Doré, F. Gunsing, D. Ridikas, CEA/DSM/IRFU/SPhN, Saclay, FranceV. Blideanu, CEA/DSM/IRFU/Senac, Saclay, FranceM. Aïche, G. Barreau, S. Czajkowski, B. Jurado, CENBG, Gradignan, FranceG. Ban, F. R. Lecolley, J. F. Lecolley, J. L. Lecouey, N. Marie, J. C. Steckmeyer, LPC, Caen, FranceP. Dessagne, M. Kerveno, G. Rudolf, IPHC, Strasbourg, FranceP. Bem, J. Mrazek, J. Novak, NPI, Řež, Czech RepublicJ. Blomgren, DNR, Uppsala, SwedenU. Fischer, S. P. Simakov, FZK, Karlsruhe, GermanyB. Jacquot, F. Rejmund, GANIL, Caen, FranceL. Perrot, L. Tassan-Got, IPNO, Orsay, FranceM. Avrigeanu, V. Avrigeanu, C. Borcea, F. Negoita, M. Petrascu, NIPNE, Bucharest, RomaniaS. Oberstedt, A.J.M. Plompen, JRC/IRMM, Geel, BelgiumO. Shcherbakov, PNPI, Gatchina, RussiaM. Fallot, L. Giot, Subatech, Nantes, FranceA. G. Smith, I. Tsekhanovich, Department of Physics and Astronomy, University of Manchester, Manchester, UKO. Serot, J.C. Sublet, CEA/DEN, Cadarache, FranceE. Balanzat, S.Bouffard, S. Guillous, J. M. Ramillon, CIMAP, Caen, FranceA. Oberstedt, Örebro University, Örebro, Sweden

neutrons for science: a neutron facility @ spiral-2...wonder, 29th september 2009 contact:...

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