CharlotteAMOUROUX1

MeasurementofthefissionmassyieldsofAm242attheLohengrin Spectrometer

A.Bidaud2,N.Capellan2,S.Chabod2,H.Faust3,G.Kessedjian2,U.Kster3,

A.Letourneau1,F.Martin2,T.Materna1,S.Panebianco1,Ch.Sage2,O.Serot4

1CEA,DSMSaclay,France2LPSCGrenoble,CNRS/IN2P3,France

3InstitutLaueLangevin,France4CEA,DENCadarache,France

242Am(Z=95)

241Am:90%oftheradiotoxicity ofthenuclearwaste (without plutonium)between 200and1000years >Transmutationof241Am

n+241 Am 242 AmFP1

FP2

242Am:two longlived statesZ=95(odd charge)

2/12CharlotteAMOUROUXWONDER25/09/2012

141Y

16.02H1

5

48.6keV

PLAN

Experimental Setup&AnalysisMethod EnergyandChargeDistributions UncertaintiesDetermination Results

CharlotteAMOUROUXWONDER25/09/2012 3/17

HighneutronfluxReactor

Target

Magnet:Selection A/q

Condenser:Selection:E/q

Detector:E

Experimental setup

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Howdowe measure theenergy ofthefragment?

E>E/q>A/q>A

*A.Bail thesis

=>Y(A,E,q)CharlotteAMOUROUXWONDER25/09/2012

EEIonisationChamber

5/17

Energy Distributionforagiven q

ChargeDistributionforagiven E

N(A,q,E)according toqandE

Valid ifnocorrelation between Eandq

Howtocalculate thefissionyields ?

Inrealitywe haveacorrelation butits influenceonY(A)inless than 3%

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Example ofQdistribution:two differents casesMeasured Chargeis determined at thelastcrossed material

(Nickel)

With nanosecond isomerWithout nanosecond isomer

QDistribution

A=105

A=136

Target

Target

NickelFoil NickelFoil

Magnet Magnet

Q~2122 Q~2425

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EDistribution

A=105Q=21

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0.6MeVfordetermination ofKE0.6MeVfor(q,E)correlation

Kinetic energy asafonctionofthefragmentmass

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EDistributionStatisticerrors:

~1%

Amplitu

de[a

.u]

Energy [MeV]

~1,5%ofthetotalarea

_

maximalfluctuationof

1,5%between 2Edistribution

~0,8%ofthetotalarea

_

maximalfluctuationof

1,0%between 2Edistribution

A=105Q=21

Systematics errors:

1,5%lowenergypart 1,0%highenergypart

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Determination ofthesystematic errorThispointis known twice

Forthesame massasafunction oftime:

Forallmasses:

~3%

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Source Contribution

Statistical ~1%

Extrapolationofthelowpartoftheenergydistribution

1.5%

Extrapolationofthehighpartoftheenergydistribution

1%

Discrepanciesbetweenthetwomeasurementsofthe

commonpoint3%

Normalisation ?

Totalofthesystematicerror 3.5%

Sourcesofrelativeuncertaintiesandtheirrespectivecontributions.

CharlotteAMOUROUXWONDER25/09/2012

n+241 Am

242m Am

242

Am

Y

Yfission=2644(281)barn*91,4%

8,6%

Y=Y ?

Objectivesoftheexperiment:

FissionMassYieldsfromAm241(2n,f)

IsthereanydifferencebetweenthefissionyieldsofAm242(n,f)andAm242m(n,f)?

FissionYields ofAm242

(141y)

(16h)

fission=6856(656)barn*

*G.Fioni etal,Nucl Phys.A693(2001)546O.Bringer,Ph.D Thesis,INP Grenoble,

October 2007

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Howdowe proceed toobserveapossibledifference ?

B:vaccum problemA:Strong evolution ofthepropertiesofthetarget (largeenergy shift)

A

Shutdow

nofthe

reactor

B

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Hypothesis:X=0.

forX=0(0,04forallYand0,07forYm )

Generalcase: ~1

What is themaximumpossibledifference ?

n+241 Am242m Am

242

Am

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Conclusions

Nodifference between theyields:quantificationongoing.

Ifyou assumethey areequal

NormalisationY105=6,5%

Onlystatisticalerror

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Isotopic fissionyields

Future

239Pu233U

*A.Bail Thesis *MeetingGEDEPEONJan2011G.Kessedjian (F.Martin thesis (ongoing))

241Pu

242AmThank you

for your attention

235U

Backup

18

Comparaisonwith theGEFcode(June 2012)

19

Number offissions

20

Evolutionofthekinetic energy asafunction oftime

21

FWHMoftheenergy distributionasafunction oftime

22

PLANHow do we proceed to observe a possible difference ?Conclusions