Jon Wilson IPN Orsay

LICORNE: A new & unique facility for producing
intense kinematically focused neutron beams
Jon Wilson IPN Orsay
Unité mixte de recherche
CNRS-IN2P3
Université Paris-Sud 11
91406 Orsay cedex
Tél. : +33 1 69 15 73 40
Fax : +33 1 69 15 64 70
http://ipnweb.in2p3.fr
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• 10% of energy released in a reactor is in the form of gamma rays
•  Gamma heating dominates in non-fissile components:
(structural materials, reflectors, fertile blankets,instrumentation, etc.)
•  In-core gamma heating effects underestimated by 30%
•  Top of the OCDE/NEA high priority list
Need to measure how spectral shape, average multiplicity and energy
change as a function of incident neutron energy and fissile nucleus:
233U, 235U, 239Pu (232Th, 238U)
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Lab beam reac)on n/s Sample distance Gelina 100uA e-­‐ (100 MeV) photofission 1013 10 – 50 m nTOF (CERN) 100uA p (24 GeV) Pb spalla)on 1015 185 m NFS (Spiral2) 1mA deuterons Breakup 9Be 1015 5 -­‐ 20 m Primary
Beam
(pulsed)
Neutron energy measured
by TOF
5 m -185 m
Thick target
Brute force + collimation
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108 n/s
Sample
1-3 cm
5-10 cm
Fluxes typically
106 n/cm2/s
Ø Typically over 99% of neutrons ‘’wasted’’
Ø Wasted neutrons contribute to the room background
Ø Placement of gamma detectors impossible without heavy shielding
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H target
n
n
n
100nA 7Li
13-17 MeV
n
Lithium Inverse Cinematiques ORsay NEutron source
Ø  p(7Li,7Be)n reaction in inverse kinematics
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7Li
p
7Be
n
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8
Neutron Flux/ MeV
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MONNET
(IRMM)
Bruyeres
LICORNE
AFIRA
(CENBG)
NFS
nTOF
GELINA
Degree of collimation
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GOALS
1. 
2. 
3. 
4. 
Tes)ng of two types of solid H-­‐rich targets Valida)on of the inverse kinema)cs Understanding of the maximum fluxes available Understanding of the backgrounds from parasi)c processes (e.g. 7Li +12C) 5.  Characterising the room background 6.  Understanding the radia)on protec)on limits 10
25 um Au 200nm Au TiH2 PP 50um Au mardi 11 juin 13
Foil Power deposited Polypropylene (7Li @ 15 MeV, 90nA) 15 mW Au beam stop (7Li @ 15 MeV, 90nA) 0.5 W (IRMM 10uA, 5 MeV deuterons) 50 W 11
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Neutrons
Time of flight TOF (ns)
Gammas
Pulse Shape Analysis (PSA)
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2.8 MeV
700 keV
7Li + 12C reaction
evaporated neutrons
Uncorrelated room background
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50um Au PP 15 mW
25 um Au 200nm Au TiH2 mardi 11 juin 13
0.5 W
2.8 MeV
4 µm
700 keV
2 µm
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All specs
P. Halipré, PhD thesis
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15 MeV
P. Halipré, PhD thesis
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Thin PP target
Thick PP target
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Maximum flux assuming 100nA of 7Li: Thin Target = 2x107 n/s/steradian 7 n/s/steradian Thick T
arget =
7
x10
Total flux
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J. Bettane
Beam current &
beam time
structure
measurement
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Commisioning June 2013. First experiment July 2013
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21
7Li
beam
100 nA @13.5
MeV
LaBr3 from IPN & IRMM
(δt = 300 ps; δE = <3% @ .662 MeV)
BaF2 from
Château de Cristal
(δt = 600 ps; δE = 10% @ 1.3
MeV)
Ionisation Chamber
238U target
n cone
emission
(< 10°)
Collaboraters from the IRMM:
S. Oberstedt, A. Oberstedt and
R. Billnert
7 mg; ø = 7 cm; ~9µm thick
(δt = 700 ps; δE = 500 keV; ε =
100%)
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Thick sample
(~100g 238U disc)
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238U(n,f)
Three neutrons further from stability
than EXILL 235U(n,f) @ ILL
-9
Prompt γ’s
10 ns – 10 µs
-8
-7
log10 t (ns)
-6
Delayed γ’s
-5
-4
Eγ
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149Pm
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149Pmm
87,88,89Ga
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TIPS – Tagging Isomer PartnerS
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•  LICORNE is a new and unique fast neutron source
using inverse kinematics
•  Combines the best aspects of both mono-energetic
sources (high flux/MeV) and white sources (a natural
collimation).
•  Designed for prompt fission gamma measurements, but
is probably useful for all kinds of other things
•  New physics possibilities may be opened up thanks to
the unique directionality of the source
•  LICORNE is open for business at the IPN!
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Calculation based on: 25 nA 7Li (pulsed beam)
→ 10 kHz fission rate
106 n/s irradiating 238U sample (200g)
Neutrons from… Flux in 1 ORGAM Ge detector Direct LICORNE neutrons p(7Li,7Be)n 0 n/s Prompt fission 175 n/s Elas)c scafering on 238U 56 n/s Parasi)c neutrons e.g. 185 n/s 12C(7Li,18F)n Room return neutrons 8 n/s 34