double chooz experiment and applied neutrino physics

INPC2007-Tokyo Lhuillier David - CEA Saclay - France 1

Double Chooz Experiment Double Chooz Experiment and Applied Neutrino and Applied Neutrino

PhysicsPhysics

CEA Saclay : M. Cribier, T. Lasserre, A. Letourneau, D. Lhuillier, T. MuellerSUBATECH-NANTES: S. Cormon, M. Fallot, L.Giot, B. Guillon, J.

Martino, J.H. Xu

http://doublechooz.in2p3.fr/

Search for 13

• Simulation of e- and energy spectra• Applied physics: power measurement, non-proliferation


PHASE 1 (2009-10) - Far detector only - sin2(213)<0.06 (1,5 years,90% C.L.) PHASE 2 (2011…) - Far + Near sites - sin2(213)<0.025 (3 years,90% C.L.)

2 identical 8.3t targets

flux Normalizati

on

@280m

oscillat

ion

@1050m

Double Chooz ExperimentDouble Chooz Experiment

2 PWR-N42x4.27 GWth


€

e + p→ e+ + n

€

Gd* →Gd + γ ('s)


Accurate Simulation of Accurate Simulation of Reactor Antineutrino Reactor Antineutrino

SpectraSpectra

• Determine normalization and shape for phase 1 (dominant error)

• Use near detector to validate studies of applied neutrino physics:

- Power measurement

- Non-proliferation


Principle of our Principle of our ApproachApproach

Evolution code: MURE

fissilemat. + FY

neutron flux

Core geometry

isotope abundances

spectra database for all

isotopes

branch spectrum:BESTIOLE

nuclear database

exp. spectrum

models

Weighted

Total and e- energy spectra with complete error treatment


Evolution Code MUREEvolution Code MUREMCNP Utility for Reactor

Evolution

• Neutron flux automatically adjusted to total power parameter• Evolution equations and time step sizes validated, propagation of fission yield error• Account for neutron capture (V. Kopeikin et al., Phys. Atom. Nucl. 67 (2004) 1963)•Working on the geometry of a N4 reactor core


Simulation of Chooz Simulation of Chooz ReactorsReactors

2 PWR - N42x4.27 GWth

Control rods (Instrumentation, Poisons…)

Zircalloy

205 Assembli

es264 rods

Fuel Assembly

(0.2x0.2x4.8m)Fuel rod

(D: 0.8 cm ; h:4.8 m)

Fuel UO2

pellets(2.1, 2.6, 3.1 % enrichment)

- Fuel: enriched Uranium - Moderator/Coolant: Light pressurized Water (155 Bar, 600K)

CPU limited, working on suitable sym. and approx.Full power and burn up info from electricity company during data taking

Core


Building Total eBuilding Total e-- and and SpectraSpectra

•Collect all available exp. info on individual branches•Remaining short-lived, high Q, nuclei described by nuclear models.•Propagate all errors and compute correlations for any combination of fissile materials and any irradiation time.•Final cross-check with integral measurements.

dN/dE = n Yn(Z,A,t) i BRn,i P(E,E0i,Z)

Fission yields branching ratios for decay branch i with endpoint E0

i

shape

StrategyStrategy:

Reactor spectrum: Reactor spectrum: Sum of “n” isotopes of “i” branches


P(E,E0i,Z)

Coulombcorrections

Phase space

Spectral Shape factorWell controlled for

allowed and forbidden unique transitions

. Sn(E)

E0=Ee+Efor each branch

info on all branches unambiguous conversion to spectrum

spectrum:

spectrum:

F(Z,E) . pE(E0i-E)2

Energy Energy SpectruSpectru

mm


IntegralIntegralValidationValidation

electrone235U1.5 days

Agreement within 1up to 6 MeV

950 nuclei, ~10000 branchesValidation of spectrum shapeNo absolute normalization yet


Error Error BarsBars

•Expect final error bar comparable to integral data: BR, E0,Shape included, working on fission yields error

•Computation of correlations on progress -->Significant gain in sensitivity to shape distortions because most errors induce large correlations (Pth, Y, BR, E0).

Good control of low energy part

[1.8-6] MeVRelevant fornormalization of phase 1


Power MeasurementPower Measurement

€

Nν

= γ 1+ k(t)( )Pthermal

Burn up effect: Project of miniature detector based on

Double Chooz conceptTo be installed ~10m from reactor core

Unique tool for cross-calibration of reactor cores !


NonNonProliferatiProliferati

onon235U 239Pu

E/fission 201.7 MeV 210.0 MeV

Mean energy

2.94 MeV 2.84 MeV

/fission > 1.8 MeV

1.92 1.45

<> for interaction

3.2 10-43 cm2

2.7 10-43 cm2

For a fixed thermal power, the measured e fluxes from pure 235U or 239Pu would differ by 55%…but realistic scenario implies tiny effect.


ConclusionConclusion

•Promising preliminary results for normalization of Double Chooz phase 1.

-Original approach with complete treatment of error bars and their correlations (expected to be large)

•Same simulation package is a key element of future applied physics:

-Project of 2-3%power measurement with miniature detector

-non-proliferation. Looks difficult, first goal is to determine detection threshold for removed Pu mass and point out critical unknown nuclei to increase sensitivity


Backup SlicesBackup Slices


Double Chooz ConceptDouble Chooz Concept P

(e

e)

=

1-s

in2(2

13)s

in2(

m2 31

L/4

E)

Ne

ar

de

tect

or

Fa

r d

ete

cto

r

Disappearance experimentClean measurement

of 13

€

L m[ ] Eν = 3MeV( )

flux : 1021 e/s

Nuclear power station 2 cores: 4.27 GWth

Near detector ~280 m Far detector 1050 m

e e,,

€

m132 = 2.5 10-3 eV

3.0 10-3 eV


Expected Oscillation Expected Oscillation SignalSignal

Far Spectrum

Near Spectrum

Far/Near ratio Far/Near ratio

sin2(213)=0.12

m2atm= 3.0 10-3 eV2

Aft

er 3

yea

rs

Assuming:


Previous StudiesPrevious Studies

Theoretical approach : Klapdor & Metzinger microscopic calc. of trans. matrix elements (PLB82 + PRL82), Vogel et al. for 238U

Integral spectra measured by Schreckenbach et al. (at better than 2% until 8 MeV) & Hahn et al. @ILL 235U, 239,241Pu targets, (PLB218(1989)365)but conversion : global fit including 30 arbitrary contributions: global shape uncertainty from 1.3%@3MeV to 9%@8MeV

FP contributions : measurements of Tengblad et al. (NPA503(1989)136) 111 nuclei @ISOLDE don’t agree with the experimental integral spectra (important errors : 5% at 4MeV, 11% at 5MeV and 20% at 8MeV)

Chooz and Bugey : energy spectrum and flux in agreement with Scheckenbach et al. + Vogel et al. for 238U, 1.9 % error on reactor e flux


Exp. Spectra of Fission Exp. Spectra of Fission ProductsProducts

2211

•48 nuclei in perfect agreement with our database

•Remaining 63 replaced.

•Correct error estimate requires careful treatment of fit correlations

111 fission products measured by Tengblad’s et al at ISOLDE


Bestiole Data Base

root and asciiformats

• 950 nuclei ~10000 branches 500 -n branches

• Interfaced to various sources of information

• tag all relevant info (forbiddenness, level of approx., …)

BDBBDB


Electron spectra

Error BarsError Bars

•Requires spin and parity of nuclear levels

•No predictions for non-unique transitions

•Use envelop of illustrated shapes to determine error(extra info from exp. shape factors)

Spectrum Shape

Quote preliminary ±2.5% sys. error


Errors on all branches treated as independent…. Converges as

€

NBranches

Error Error BarsBars

•

• BR

From ENSDF nuclear database:


Treatment of Treatment of CorrelationsCorrelations

€

χ 2 =Ri − Si( )

2

σ iR

( )2

+ σ iS

( )2

i

∑χ2 test of two independent data sets:

€

χ 2 = Ri − Si[ ]tVij

−1 Rj − Sj[ ]i, j

∑

€

Vij = Ri − Si( ) R j − S j( ) − Ri − Si R j − S j

€

Vij =VijR +Vij

S −VijRS −Vij

SR

Generalized χ2 test with correlated errors:

,

Adapted to different studies: -Oscillations: data (R) vs simul (S) -Non prolif: simul vs simul

Numerically computed

Expect large gain in sensitivity to shape distortions because most errors induce large correlations (Pth, Y, BR, E0).


Models for Unknown Models for Unknown spectraspectra

BESTIOLE + Tengblad et al.(JEF2.2) + Qbeta

approx

BESTIOLE +Tengblad et al. (JEF2.2) + Gross Theory from ENDFBVI, JENDL and JEFF3.1


Pandemonium EffectPandemonium Effect

0

0

Z NA

Z-1N’A

If not included in database: - Underestimation of the low E part of the spectrum w.r.t. high energy part- Tengblad’s measurement, not sensitive to pandemonium, partly correct for this effect

det drops fast with E

+difficult analysis

of continuum


Previous Power Previous Power MeasurementsMeasurements


SONGSSONGS

San Onofre Nuclear Generating Station

Lawrence Livermore and

Sandia National Labs

Detector located in tendon gallery:

det ~ 10%

•469 evts/day

Evidencefor burn up effect (?)

double chooz experiment and applied neutrino physics

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