LEgnaro NeutrOn Source  P.F.Mas(nu1,J.Praena1,3,G.Mar2nHernández2

1LaboratoriNazionalidiLegnaro,INFN,Italia.2CEADEN,LaHabana,Cuba.

3UniversidaddeSevilla,CNA,Spain.

WhatwouldbeLenos?

•  FacilityforNeutronAc(va(on(NA)•  PossiblefutureupgradewithaTOFline.•  MeasurementsofshortmeanlifeisotopestargetsimplantedwithSPESTheIdea:shapetheprotonbeamtoshapethe

neutronbeamtoadesireddistribu(on

•  NuclearAstrophysics.•  Valida(onofEvaluatedDataforenergyandnon‐energyapplica(ons

Lenos collaboration is completly open to new applications and collaborations

Mo(va(ons

Mo(va(ons:Astrophysics(1/3)

Nucleosynthesis of elements beyond Fe (B=8.8 MeV/A) are produced in stars (mainly AGB and Massive star) by (n,γ). Stellar neutron distribution is Maxwell Boltzmann. Depending on the stellar site and shell the most important kT are 8, 30 or 90keV.

MACS (Maxwellian Averaged Cross Section)

r‐process• Short(mescale.• Highneutronflux:1020cm‐3.• relatedtoexplosivescenarios.Wai(ngpoint

Mo(va(ons:Astrophysics(2/3)

s‐process

Branchingpointsareunstable(SPESRIB)andcanbeusedtodeterminetheenviromentalquan(ty(density,neutronfluxandtemperature).

THE PROBLEM •  The uncertainties in the MACS of several

stable and most of the unstable elements are higher than the requested accuracy.

•  Required uncertainties for s-process: 3-5%

Mo(va(ons:Astrophysics(3/3)

Main library

for MACS

Most of the MACS at kT=30keV were not measured directly. It has been extrapolated from 25kT=keV

First application of Lenos could be the measurement of the most important isotopes at kT=30 keV.

Long list of branching points for which the MACS has not jet been measured: 63Ni, 79Se, 85Kr, 95Zr, 147Nd, 147,148Pm, 154,155Eu, 153Gd, 160Tb, 163Ho, 170,171Tm, 179Ta, 185W, 204Tl…

Some actinides for AFC and Gen-IV: Pu-239 fission in 1 keV – 1 MeV Pu-241 fission in 1 keV – 1 MeV U-238 capture in 2 – 200 keV Am-243 capture in fast and thermal energy range Am-241fission in fast energy range

P. Oblozinsky, NNDC

Mo(va(ons:Valida(onofEvaluated

NuclearData

Often large discrepances between data bases (ENDF,JENDL,JEFF,BRONDL) for many already mesured isotopes. No mesurements for some important isotopes (mainly radioactive)

Mo(va(ons:Valida(onofEvaluated

NuclearData

•  Awellcaractherizedneutronspectrumitisneededforvalida(onofEvaluatedData(integralmeasurements),mainlyonepithermalrange.

•  Asitwillbeshowninthispresenta(onshouldbepossibletohaveaquasiperfectneutronmaxwellianspectrum.AtleastatkT=30keV.

•  Withthesametechniquea

1/Ebehaviourshouldbepossible

SPES @ LNL 

• RFQ:

• Cyclotron:

Previous…

PRC 21 2 (1980) 7Li(p,n),kT=25keV.Ep=1.912MeV,Ι=110μA

Φn=3⋅109n/son0.36cm2

Imax=200µA

Correc(ons

5MeV protons

Ι=30-50mA

70MeV protons, Ι=1.2mA

high intensity low-energy RIB by 238U(p,f)

TheLenosidea…

•  Shaping the proton beam of the RFQ in order to obtain a desired neutron spectrum avoiding neutron moderaEon. 

Firstapplica(on•  MaxwellianneutronspectrumatkT=30keVwithhighspecificneutronflux

OVERVIEW

Multilayer Li target

Multilayer Energy Shaper

Sample

SPES RIB

RFQ

beam Chopper +

Wien Filter

DESIRED

NEUTRON

SPECRA

Beam Dump and Faraday Cup

P=164 kw P≈5 kw

Thefacility:(1/6)Mul(layerCarbonEnergyShaper

Conceptualdesign

Targetsurfacedividedintomanyareas,eachofthemwithadifferent(ckness.minimiza(onproceduretofitthenumber,(cknessandareaofeachlayerTicknessmeanprotonenergyofGaussian‐likedistribu(onAreaweightofthecorrespondingprotonenergydistribu(on

Thefinalshapeoftheprotonbeamisgivenbytheconvolu(onofthedifferentgaussian‐likedistribu(onweightedbytheocuupaiedarea.Thesametechiniquecanbeusedforapar(allythickLithiumtarget

Thefacility:(2/6)Mul(layerCarbonEnergyShaper

•  With a rota(ng mul(layer carbon shaper is possible to obtain a neutron distribu(on with R2=0.999 respect to a Maxwelliandistribu(onatkT=30keV.

•  IncaseofMaxwellianatkT=30keVispossibletoobtainadistribu(onwithR2=0.998usingamonolayercarbonshaperof152µmthickness.

•  ItisacompromisebetweenR2,neutronyieldandcomplexity.

NIM

B 1

52 1

999

P=164kW for 50mA

ANSYS, Inc

•  Deflec(onofprotonswithenergyunderthe7Li(p,n)7Bereac(onthreshold(1.88MeV).

•  ReducedpowerdissipatedonLitarget.•  Only5%ofprotonsontheLitarget.•  BeamdumponCopperbacking

SRIM

Thefacility:(3/6)WienFilter

•  ∼3kW/cm2couldbedissipated.Tli<152°C.Mel(ngpointat182°C.

•  Li(30µm)onabackingofCu(1.5mm).•  Microchannels,flowingHgliquidascoolantatT=‐20°CorGaSnI

alloyatT=15°C

Proton beam profile

Temperature of Li surface

ANSYS, Inc

Thefacility:(4/6)Lithiumtarget

RIB

1013 f/s

109-11 ion/s

•  NeutronyieldsNIMB 152 (1999). 

•  AllsecondaryeffectsaccountwithMCNPXsimula(on.

Neutron Flux = 5⋅1010 n/s⋅cm2

NEUTRONS

SAMPLE •  RIB implantation •  Neutron irradiation

Thefacility:(5/6)Theresults…

Cyclotron Protons

70MeV, 1mA

238U target ALPI

Beam Selection

Li target Energy Shaper

Sample

SPES RIB RFQ

beam Wien Filter

•  Tcarbon << Melting point. Radiation heat removing.

•  5 % proton beam, but no neutron moderation needed.

•  It should be possible to dissipate P=3 kW/cm2 on Li.

•  ANSYS calculation, Maximum Temperature (Li) ≈152ºC <TMelting = 180ºC

Thefacility:(5/6)Resume

NEUTRON

SPECRA

Thankyou