Future Physics and Detectors at n _TOF

Alberto MengoniAlberto MengoniIAEA , ViennaIAEA , Vienna

www.cern.ch/n_TOF

Experimental characteristics of the Experimental characteristics of the

n_TOF beam & detection setupn_TOF beam & detection setup

n_TOF-Phase n_TOF-Phase 22

Future Physics and Detectors Future Physics and Detectors at at nn_TOF_TOF

Basic characteristics of Basic characteristics of experiments at experiments at nn_TOF _TOF

The n_TOF Collaborationwww.cern.ch/n_TOF

wide energy rangewide energy range



wide energy rangewide energy range

1 10 100 1000 10000 100000 1000000 1E7 1E80.00.10.20.3

1

10

n_TOF James Lestone ENDF-B/VI

f, b

arns

En, eV

234U(n,f)PPACs & FIC-0 (2003)



wide energy rangewide energy range high neutron flux & high neutron flux &

high energy resolutionhigh energy resolution

232Th(n,)

small small samplessamples





236U(n,f)

1150 1200 1250 1300 1350 14000

300

600

900

CERN 2003

FIS

SIO

N C

RO

SS

-SE

CT

ION

, mb

NEUTRON ENERGY, eV

1150 1200 1250 1300 1350 14000

30

60

90

120

150

POMMARD





93Zr(n,)




high energy resolutionhigh energy resolution low repetition rate low repetition rate

of the proton driverof the proton driver

comparison with GELINA (~ same average flux at 30m)comparison with GELINA (~ same average flux at 30m)

232Th(n,)

10 100 1000 10000 10000010-1

100

101

102

Re

spo

nse

(co

un

ts /

ns)

Neutron Energy / eV

n-TOF

232Th (0.0041 at/b)

208Pb

GELINA

232Th (0.0016 at/b)

208Pb

source: P Rullhusen (GELINA)source: P Rullhusen (GELINA)





of the proton driverof the proton driver low background conditionslow background conditions

U Abbondanno et al. (The n_TOF Collaboration)Phys. Rev. Lett. 93 (2004), 161103

&S Marrone et al. (The n_TOF Collaboration)

Phys. Rev. C 7373 03604 (2006)151Sm(n,)






237Np(n,)D Cano-Ott, et al. (The n_TOF Collaboration)

ND2004 Conference, Santa Fe, NM – Sept. 2004






WARNING:WARNING:

important in-beamimportant in-beam

-ray BG present-ray BG present

low background conditions, but…

In-beam photon time In-beam photon time distributiondistribution

Time [s]

simulations: V Vlachoudissimulations: V Vlachoudis

In-beam photon time In-beam photon time distribution distribution (E(E>1MeV)>1MeV)

Time [s]simulations: V Vlachoudissimulations: V Vlachoudis






detectors with extremely detectors with extremely low neutron sensitivitylow neutron sensitivity

R Plag et al. (The n_TOF Collaboration)NIMA 496 (2003) 425







C6D6

C6D6

Neutron beam

Sample changer







sample changer and beam pipe made out of carbon fiber







high-efficiency detectors (TAC)high-efficiency detectors (TAC)

sample

≤ ≤ 2%2%

• 40 BaF2 crystals• high detection efficiency ≈100%• good energy resolution• so far, only used for (n,) measurements in 2004







high-efficiency detectors (TAC)high-efficiency detectors (TAC)

240Pu(n,)C Guerrero et al. (The n_TOF Collaboration)

ND2007 Conference, Nice, France, April 2007







high-efficiency detectors (TAC)high-efficiency detectors (TAC) state of the art daq systemstate of the art daq system

R Plag et al. (The n_TOF Collaboration)NIMA 538 (2005) 693







high-efficiency detectors (TAC)high-efficiency detectors (TAC) state of the art daq systemstate of the art daq system

n_TOF beam characteristics n_TOF beam characteristics and experimental setup and experimental setup proved to be a unique proved to be a unique combination for high combination for high

accuracy measurementsaccuracy measurements

nn_TOF experiments _TOF experiments 20020022--44CCaptureapture

151151SmSm

204,206,207,208204,206,207,208PbPb, , 209209BiBi

232232ThTh

24,25,2624,25,26MgMg

90,91,92,94,9690,91,92,94,96ZrZr, , 9393ZrZr

139139LaLa

186,187,188186,187,188OsOs

233,234233,234UU

237237NpNp,,240240PuPu,,243243AmAm

FFissionission233,234,235,236,238233,234,235,236,238UU

232232ThTh

209209BiBi237237NpNp

241,243241,243Am, Am, 245245CmCm

MMeasurements of neutron cross sections easurements of neutron cross sections relevant for Nuclear Waste Transmutation and relevant for Nuclear Waste Transmutation and related Nuclear Technologiesrelated Nuclear Technologies

Th/U fuel cycle (capture & fission)Th/U fuel cycle (capture & fission) Transmutation of MA (capture & fission)Transmutation of MA (capture & fission) Transmutation of FP (capture)Transmutation of FP (capture)

CCross sections relevant for Nuclear ross sections relevant for Nuclear AstrophysicsAstrophysics

s-process: branchingss-process: branchings s-process: presolar grainss-process: presolar grains

NNeutrons as probes for fundamental Nuclear eutrons as probes for fundamental Nuclear PhysicsPhysics

Nuclear level density & n-nucleus interactionNuclear level density & n-nucleus interaction

The n_TOF Collaboration

The n_TOF-PhThe n_TOF-Ph22(*) experiments(*) experiments20020088 and beyond and beyond

n_TOF-Ph2

MMeasurements of neutron cross sections relevant for Nuclear easurements of neutron cross sections relevant for Nuclear Waste Transmutation and Advanced Nuclear TechnologiesWaste Transmutation and Advanced Nuclear Technologies

CCross sections relevant for Nuclear Astrophysicsross sections relevant for Nuclear Astrophysics

NNeutrons as probes for fundamental Nuclear Physicseutrons as probes for fundamental Nuclear Physics

(*) The physics case and the related proposal for measurements at the CERN Neutron Time-of-Flight facility n_TOF in the period 2006-2010CERN-INTC-2005-021; INTC-P-197April 2005

The n_TOF-PhThe n_TOF-Ph22 experiments experiments20020088 and beyond and beyond

Capture measurementsCapture measurementsMo, Ru, Pd stable isotopes

Fe, Ni, Zn, and Se (stable isotopes)79Se

A≈150 (isotopes varii)

234,236U, 231,233Pa

235,238U

239,240,242Pu, 241,243Am, 245Cm

r-process residuals calculationisotopic patterns in SiC grains

s-process nucleosynthesis in massive starsaccurate nuclear data needs for structural materials

s-process branching pointslong-lived fission products

Th/U nuclear fuel cycle

standards, conventional U/Pu fuel cycle

incineration of minor actinides

n_TOF-Ph2

(*) endorsed by CERN INTC (execution in 2008?)

Fission measurementsFission measurementsMA

235U(n,f) with p(n,p’)

234U(n,f)

ADS, high-burnup, GEN-IV reactors

new 235U(n,f) cross section standard

study of vibrational resonances at the fission barrier

Other measurementsOther measurements147Sm(n,a), 67Zn(n,a), 99Ru(n,a)

58Ni(n,p), other (n,lcp)

Al, V, Cr, Zr, Th, 238U(n,lcp)

He, Ne, Ar, Xe

n+D2

p-process studiesgas production in structural materials

structural and fuel material for ADS and other advanced nuclear reactors

low-energy nuclear recoils (development of gas detectors)

neutron-neutron scattering length

n_TOF-Ph2

The n_TOF-PhThe n_TOF-Ph22 experiments experiments20020088 and beyond and beyond

n_TOF-Ph2

n_TOF targetn_TOF target

NewExperimentalArea (EAR-2)

The second n_TOF beam line & The second n_TOF beam line & EAR-2EAR-2

EAR-1 (at 185 m)

~ 20 m~ 20 m

Flight-path length : Flight-path length : ~~20 m20 mat 90at 90° respect to p-beam direction° respect to p-beam directionexpected neutron flux enhancement: ~ 100expected neutron flux enhancement: ~ 100drastic reduction of the tdrastic reduction of the t00 flash flash

Flight-path length : Flight-path length : ~~20 m20 mat 90at 90° respect to p-beam direction° respect to p-beam directionexpected neutron flux enhancement: ~ 100expected neutron flux enhancement: ~ 100drastic reduction of the tdrastic reduction of the t00 flash flash

Improvements (ex: Improvements (ex: 151151Sm case)Sm case)

sample mass / 3 sample mass / 3 s/bkgd=1s/bkgd=1 use BaFuse BaF22 TAC TAC x 10 x 10 use Duse D22OO 3030 x 5 x 5 use 20 m flight pathuse 20 m flight path 3030 x 100 x 100

consequences for consequences for sample masssample mass

50 mg50 mg

5 mg 5 mg 1 mg1 mg 10 10 gg

boosts sensitivity by a factor of 5000 !

problems of sample production and safety issues relaxed

EAR-EAR-22: Optimized sensitivity: Optimized sensitivity

Summary & conclusionSummary & conclusion

www.cern.ch/n_TOF

n_TOF unique for high precision cross section measurementsn_TOF unique for high precision cross section measurements plan for measurements in EAR-1 already available plan for measurements in EAR-1 already available

ready to restart activities!ready to restart activities!

possible improvements for the present setup for EAR-1:possible improvements for the present setup for EAR-1: reduction of in-beam reduction of in-beam -ray (use Borated H-ray (use Borated H22O or DO or D22O)O) mods to safe use of radioactive samplesmods to safe use of radioactive samples

future perspectives:future perspectives: second beam line construction plansecond beam line construction plan Class-A as EAR-2Class-A as EAR-2

The The nn_TOF Collaboration_TOF Collaboration

40 research teams40 research teams120 researchers 120 researchers

www.cern.ch/n_TOF

MoU for Phase-2MoU for Phase-2ready for signatureready for signature

The The EEndnd

www.cern.ch/n_TOF

CCaptureapture151151SmSm204,206,207,208204,206,207,208Pb, Pb, 209209BiBi232232ThTh24,25,2624,25,26MgMg90,91,92,94,9690,91,92,94,96Zr, Zr, 9393ZrZr139139LaLa186,187,188186,187,188OsOs233,234233,234UU237237Np,Np,240240Pu,Pu,243243AmAm

FissionFission233,234,235,236,238233,234,235,236,238UU232232ThTh209209BiBi237237NpNp241,243241,243Am, Am, 245245CmCm

nn_TOF experiments_TOF experimentsU Abbondanno et al. (The n_TOF Collaboration)

Phys. Rev. Lett. 93 (2004), 161103




Phys. Rev. Lett. 93 (2004), 161103&

S Marrone et al. (The n_TOF Collaboration)Phys. Rev. C 73 03604 (2006)



nn_TOF experiments_TOF experiments

<D0> = 1.49 ± 0.07 eV S0 = (3.87 ± 0.33)×10-4

RI = 3575 ± 210 b

n_TOF



&S Marrone et al. (The n_TOF Collaboration)

Phys. Rev. C 73 03604 (2006)


• T8 > 4 using the “classical” s-process model• from AGB modeling: 71% of 152Gd

Present main uncertainty: (T) of 151Sm

Sm

Eu

Gd

150Sm

151Sm 93 a

152Sm

153Sm

154Sm

151Eu

152Eu

153Eu

154Eu

155Eu

156Eu

152Gd

153Gd

154Gd

155Gd

156Gd

157Gd









Phys. Rev. Lett. 93 (2004), 161103&


for nuclear dataevaluators:all infos available inrefereed journal publications&on the n_TOF websitewww.cern.ch/ntof



nn_TOF experiments_TOF experiments207Pb(n,)


C Domingo-Pardo, et al. - The n_TOF CollaborationND2004 Conference, Santa Fe, NM – Sept. 2004

&accepted for publication in PRC (in press)




substantial disagreement for Esubstantial disagreement for Enn > 45 keV > 45 keV

207Pb(n,)







3% accuracy 3% accuracy of the capture kernelof the capture kernel

207Pb(n,)







Very low neutron sensitivity of capture Very low neutron sensitivity of capture -ray-raydetection systems & high resolutiondetection systems & high resolution


&submitted for publication to PRC, October 2006

204Pb(n,)




nn_TOF experiments_TOF experimentsC Domingo-Pardo, et al. - The n_TOF Collaboration

ND2004 Conference, Santa Fe, NM – Sept. 2004&

submitted for publication to PRC, October 2006

204Pb(n,)






209Bi(n,)


C Domingo-Pardo, et al. (The n_TOF Collaboration)Phys. Rev. C 74, 025807 (2006)






C Domingo-Pardo, et al. (The n_TOF Collaboration)Phys. Rev. C 74, 025807 (2006)209Bi(n,)




16% higher MACS for kT = 5-8 keV16% higher MACS for kT = 5-8 keV81% r-process abundance for 81% r-process abundance for 209209BiBi


C Domingo-Pardo, et al. (The n_TOF Collaboration)Phys. Rev. C 74, 025807 (2006)209Bi(n,)



nn_TOF experiments_TOF experimentsF Gunsing, et al. - The n_TOF Collaboration

ND2004 Conference, Santa Fe, NM – Sept. 2004232Th(n,)


extremely high-resolution data!extremely high-resolution data!





G Aerts et al. (The n_TOF Collaboration)Phys. Rev. C 73, 054610 (2006)

232Th(n,)






G Aerts et al. (The n_TOF Collaboration)Phys. Rev. C 73, 054610 (2006)

232Th(n,)


For En = 4 keV up to 1 MeV full dataset is available on the PRC publication




F Gunsing, et al. - The n_TOF Collaborationanalysis in progress

232Th(n,)





F Gunsing, et al. - The n_TOF Collaborationanalysis in progress

232Th(n,)


s-wave resonancess-wave resonances






Fitting of resonance parameter in progress!

first known Mg resonance at 24 keV

ImpuritiesIn, Sb




Capture & transmission data (from ORELA)Capture & transmission data (from ORELA)analyzed simultanouslyanalyzed simultanously


Source: P Koehler & S O’Brien



nn_TOF experiments_TOF experimentsC Moreau, et al. - The n_TOF Collaboration

ND2004 Conference, Santa Fe, NM – September 2004G Tagliente et al. (The n_TOF Collaboration)

NIC-IX, CERN, June 2006


96Zr(n,)

20% reduction20% reductionin the capture in the capture strength strength (average)(average)

C Moreau, et al. - The n_TOF CollaborationND2004 Conference, Santa Fe, NM – September 2004

G Tagliente et al. (The n_TOF Collaboration)NIC-IX, CERN, June 2006



nn_TOF experiments_TOF experimentsC Moreau, et al. - The n_TOF Collaboration

ND2004 Conference, Santa Fe, NM – September 2004G Tagliente et al. (The n_TOF Collaboration)

NIC-IX, CERN, June 2006


90Zr(n,)



nn_TOF experiments_TOF experiments93Zr(n,): raw data

10 mm




nn_TOF experiments_TOF experimentsR Terlizzi, et al. (The n_TOF Collaboration)

CGS12Notre Dame, IN, USA

AIP Conference Proceedings 819&



139La(n,)



nn_TOF experiments_TOF experimentsR Terlizzi, et al. (The n_TOF Collaboration)

CGS12Notre Dame, IN, USA

AIP Conference Proceedings 819&



139La(n,)




Remarkable energy resolution and background conditions Remarkable energy resolution and background conditions have allowed to determine the resonance parameters up to 9 keVhave allowed to determine the resonance parameters up to 9 keV

139La(n,)


RI = 10.8 ± 1.0 barn average γ-widths:s-waves = 50.7 ± 5.4 meV p-waves = 33.6 ± 6.9 meV<D0>= 252 ± 22 eV S0 = (0.82 ± 0.05)×10–4 S1 = (0.55 ± 0.04)×10–4




Re/Os clock



nn_TOF experiments_TOF experimentsMACS-30MACS-30

BrB81BrB81 438 438 ± 30 mb± 30 mb

WiM8WiM822

418 418 ± 16 mb± 16 mb

nn_TOF_TOF 409 409 ± 17 mb± 17 mb

M Mosconi, et al. – (The n_TOF Collaboration)NIC-IX, CERN, Geneva – June 2006analysis completed - paper in preparation



nn_TOF experiments_TOF experimentsMACS-30MACS-30

BrB81BrB81 919 919 ± 43 mb± 43 mb

WiM8WiM822

874 874 ± 28 mb± 28 mb

nn_TOF_TOF 968 968 ± 18 mb± 18 mb

M Mosconi, et al. – (The n_TOF Collaboration)NIC-IX, CERN, Geneva – June 2006analysis completed - paper in preparation

SStellar cross sections & the clock tellar cross sections & the clock

Now4.5 GyrBANG!

t0

R*= 0.36±0.02

age:

10.3+4.6=14.9 Gyr

uncertainty due to x-sections:

0.5 Gyr

<<




nn_TOF TAC in operation_TOF TAC in operation


233U(n,) W Dridi, E Berthoumieux, et al., (Dec. 2004)





233U(n,) W Dridi, E Berthoumieux, et al., CEA/SaclayPaper in preparation (October 2006)

nn_TOF TAC in operation: capture & fission discrimination_TOF TAC in operation: capture & fission discrimination





W Dridi, E Berthoumieux, et al. (The n_TOF Collaboration)PHYSOR-2006, Vancouver, September 2006

full paper in preparation


234U(n,)








234U(n,)




nn_TOF TAC in operation_TOF TAC in operationThe n_TOF Collaboration

234U(n,)







234U(n,)







234U(n,)





nn_TOF experiments_TOF experimentsD Cano-Ott, et al. - The n_TOF Collaboration


The n_TOF Collaborationnn_TOF TAC in operation_TOF TAC in operation



nn_TOF experiments_TOF experimentsC Guerero, D Cano-Ott, et al. - The n_TOF CollaborationPHYSOR 2006, Vancouver, September 2006






C Guerero, D Cano-Ott, et al. - The n_TOF CollaborationPHYSOR 2006, Vancouver, September 2006





RKn_TOF on average 3% below the RKJENDL and 6% below the RKENDF






D Cano-Ott, et al. - The n_TOF CollaborationND2004 Conference, Santa Fe, NM – Sept. 2004










RKn_TOF is on average 9% smaller than RKJENDL and 7% smaller than RKENDF.




nn_TOF experiments_TOF experimentsD Cano-Ott, et al. - The n_TOF Collaboration


1% of statistics






1 10 100 1000 10000 100000 1000000 1E7 1E80.00.10.20.3

1

10

n_TOF James Lestone ENDF-B/VI

f, b

arns

En, eV

An unprecedent wide energy range can be An unprecedent wide energy range can be explored at n_TOF in a single experimentexplored at n_TOF in a single experiment

234U(n,f)


PPACs & FIC-0 (2003)




480 500 520 540 560 580 600 6200

1

2

3

4

5

6

234U(n,f)

FIS

SIO

N X

-SE

CTI

ON

, bar

b. u

.

NEUTRON ENERGY, eV

ORNL' 1977

480 500 520 540 560 580 600 620

0

200

400

600

800

1000

1200CERN' 2003

High-resolution data up to highHigh-resolution data up to high(er) energies(er) energies The n_TOF Collaboration

PPACs & FIC-0 (2003)234U(n,f)




High-resolution data up to highHigh-resolution data up to high(er) energies(er) energies The n_TOF Collaboration

PPACs & FIC-0 (2003)234U(n,f)





235U(n,f)


FIC-0 (2003)





1150 1200 1250 1300 1350 14000

300

600

900

CERN 2003

FIS

SIO

N C

RO

SS

-SE

CT

ION

, mb

NEUTRON ENERGY, eV

1150 1200 1250 1300 1350 14000

30

60

90

120

150

POMMARD236U(n,f)


FIC-1 (2003)





232Th(n,f)


PPAC detectors




Higher fission x-section in the sub-threshold regionHigher fission x-section in the sub-threshold region

237Np(n,f)


FIC-0 (2003)



nn_TOF experiments_TOF experiments237Np(n,f)


PPACs (2003)

Higher fission x-section in the sub-threshold regionHigher fission x-section in the sub-threshold region




High-resolution data up to highHigh-resolution data up to high(er) energies(er) energies

245Cm(n,f)


FIC-1 (2003)




8% lower U8/U5 ratio at high energies8% lower U8/U5 ratio at high energies

238U(n,f)/238U(n,f)


FIC-0 (2003)


back

Capture samplesCapture samplesSample A half-life half-life Lambda Mass N LA # of LA

yr s 1/s mg Bq Ci BqSm-151 151 9.30E+01 2.9E+09 2.36E-10 160 6.36E+20 1.5E+11 4.1E+00 - -U-233 233 1.59E+05 5.0E+12 1.38E-13 100 2.58E+20 3.6E+07 9.6E-04 700 50,755U-234 234 2.46E+05 7.7E+12 8.95E-14 37 9.49E+19 8.5E+06 2.3E-04 700 12,126U-236 236 2.34E+07 7.4E+14 9.38E-16 400 1.02E+21 9.5E+05 2.6E-05 800 1,192

Np-237 237 2.10E+06 6.6E+13 1.05E-14 50 1.27E+20 1.3E+06 3.6E-05 300 4,413Pu-240 240 6564 2.1E+11 3.35E-12 50 1.25E+20 4.2E+08 1.1E-02 200 2,091,380Pu-242 242 3.73E+05 1.2E+13 5.88E-14 20 4.96E+19 2.9E+06 7.9E-05 200 14,588Am-241 241 432 1.4E+10 5.08E-11 400 9.96E+20 5.1E+10 1.4E+00 200 253,164,001Am-243 243 7370 2.3E+11 2.98E-12 25 6.17E+19 1.8E+08 5.0E-03 200 919,833

Activity

sample

Fission samples (FIC Fission samples (FIC detectors)detectors)Isotope Diam. [mm] Density [g/cm2] # of targets Mass [mg] T1/2 [yr] A [Bq] A[Ci] NU-234 50 150 6 35.3 2.46E+05 8.1E+06 2.2E-04 9.1E+19U-235 50 200 2 15.7 7.04E+08 1.3E+03 3.4E-08 4.0E+19U-236 80 100 2 20.1 2.34E+07 4.8E+04 1.3E-06 5.1E+19U-238 80 300 2 60.3 4.47E+09 7.5E+02 2.0E-08 1.5E+20Th-232 80 400 2 80.4 1.41E+10 3.2E+02 8.8E-09 2.1E+20Np-237 80 150 1 15.1 2.10E+06 4.0E+05 1.1E-05 3.8E+19Am-241 80 5 4 2.0 432.2 2.5E+08 6.9E-03 5.0E+18Am-243 80 25 4 10.0 7370 7.4E+07 2.0E-03 2.5E+19Cm-245 80 10 2 2.0 8500 1.3E+07 3.4E-04 4.9E+18


back

n_TOF-Ph2

Capture studiesCapture studies

n_TOF-Ph2

Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & Se Se

Motivations: Motivations:

• Study of the weak s-process component (nucleosynthesis up to A ~ 90)

• Fe and Ni are the most important structural materials for nuclear technologies. Results of previous measurements at n_TOF show that capture rates for light and intermediate-mass isotopes need to be revised

Motivations: Motivations:

• Study of the weak s-process component (nucleosynthesis up to A ~ 90)

• Fe and Ni are the most important structural materials for nuclear technologies. Results of previous measurements at n_TOF show that capture rates for light and intermediate-mass isotopes need to be revised

• Contribution of massive stars (core He-burning phase) to the s-process Contribution of massive stars (core He-burning phase) to the s-process nucleosynthesisnucleosynthesis• s-process efficiency due to bottleneck cross sections (Example: s-process efficiency due to bottleneck cross sections (Example: 6262Ni) Ni)

• Contribution of massive stars (core He-burning phase) to the s-process Contribution of massive stars (core He-burning phase) to the s-process nucleosynthesisnucleosynthesis• s-process efficiency due to bottleneck cross sections (Example: s-process efficiency due to bottleneck cross sections (Example: 6262Ni) Ni)

<<<<

n_TOF-Ph2

32

30

34

38 40 42 44 46 48 50

Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & Se Se

The The 7979Se caseSe case

• s-process branching: neutron density & temperature s-process branching: neutron density & temperature conditions for the weak componentconditions for the weak component

• tt1/21/2 < 6.5 x 10 < 6.5 x 104 4 yryr

The The 7979Se caseSe case

• s-process branching: neutron density & temperature s-process branching: neutron density & temperature conditions for the weak componentconditions for the weak component

• tt1/21/2 < 6.5 x 10 < 6.5 x 104 4 yryr

<<<<

• Setup: CC66DD66 in EAR-1• All samples are stable(*) and non-hazardous• Metal samples preferable (oxides acceptable)

Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & SeSe

(*) except 79Se

n_TOF-Ph2

<<<<

n_TOF-Ph2

Motivations:Motivations:

• Accurate determination of the r-process Accurate determination of the r-process abundances (r-process residuals) from abundances (r-process residuals) from observationsobservations

• SiC grains carry direct information on s-process SiC grains carry direct information on s-process efficiencies in individual AGB stars. Abundance efficiencies in individual AGB stars. Abundance ratios in SiC grains strongly depend on available ratios in SiC grains strongly depend on available capture cross sections data.capture cross sections data.

Motivations:Motivations:

• Accurate determination of the r-process Accurate determination of the r-process abundances (r-process residuals) from abundances (r-process residuals) from observationsobservations

• SiC grains carry direct information on s-process SiC grains carry direct information on s-process efficiencies in individual AGB stars. Abundance efficiencies in individual AGB stars. Abundance ratios in SiC grains strongly depend on available ratios in SiC grains strongly depend on available capture cross sections data.capture cross sections data.

NNrr = N= Nsolarsolar - N - NssNNrr = N= Nsolarsolar - N - Nss

<<<<Capture studies: Mo, Ru & PdCapture studies: Mo, Ru & Pd

n_TOF-Ph2

• Setup: The n_TOF TACn_TOF TAC in EAR-1 (a few cases with C6D6 if larger neutron scattering)• All samples are stable and non-hazardous• Metal samples preferable (oxides acceptable)

Estimated # of protons 20 x 5x1016 = 10101818

sample

Capture studies: Mo, Ru & PdCapture studies: Mo, Ru & Pd <<<<

n_TOF-Ph2

Capture studies: A Capture studies: A ≈ 150≈ 150

• branching isotope in the Sm-Eu-Gd region: test for low-mass TP-AGB

• branching ratio (capture/-decay) provides infos on the thermodynamical conditions of the s-processing (if accurateaccurate capture rates are known!)

Sm

Eu

Gd

150Sm

151Sm 93 a

152Sm

153Sm 42.27 h

154Sm

151Eu

152Eu 9 h

153Eu

154Eu 8.8 a

155Eu 4.761 a

156Eu 15.2 d

152Gd

153Gd

239.47 d

154Gd

155Gd

156Gd

157Gd

• EAR-2 requiredEAR-2 required• Sample from ISOLDE?Sample from ISOLDE?• EAR-2 requiredEAR-2 required• Sample from ISOLDE?Sample from ISOLDE?

<<<<

Capture studies: actinidesCapture studies: actinides

Neutron cross section measurements for nuclear waste Neutron cross section measurements for nuclear waste transmutation and advanced nuclear technologiestransmutation and advanced nuclear technologies

241,243241,243AmAm The most important neutron poison in the fuels proposed for transmutation scenarios. Build up of Cm isotopes.

239,240,242239,240,242PuPu (n,) and (n,f) with active canning. Build up of Am and Cm isotopes.

245245CmCm No data available.

235,238235,238UU Improvement of standard cross sections.

232232Th,Th,233,234233,234UU231,233231,233PaPa

Th/U advanced nuclear fuels. 233U fission with active canning.

All measurements can be done in EAR-1 (except All measurements can be done in EAR-1 (except 241241Am and Am and 233233Pa)Pa)All measurements can be done in EAR-1 (except All measurements can be done in EAR-1 (except 241241Am and Am and 233233Pa)Pa)

<<<<

50m Kapton windows

400m ISO 2919 Ti canning (400 mg!) +

actinide sampleair

vacuum

Neutron absorber

Calorimeter

rays

Actual setup with thick sample cannings

Capture studies: actual TAC setupCapture studies: actual TAC setup

n_TOF-Ph2

<<<<

Window surrounded by neutron absorber

(10B or 6Li doped polyethylene)

Thin Al backing +

actinide sample

vacuum

Neutron absorber

Calorimeter

TAC: TAC: Low neutron sensitivity setupLow neutron sensitivity setup

n_TOF-Ph2

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C12H20O4(6Li)2

Neutron Absorber

10B loaded Carbon Fibre

Capsules

Neutron Beam

n_TOF-Ph2

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Effect of the Ti canning (neutron sensitivity)

Capture studies: actual TAC setupCapture studies: actual TAC setup<<<<

Neutron beam

Mini Ionisation chamber

Stack of with 200 g/cm2

samples on thin backings

Fission Fragments

rays

Measurement of capture cross sections of fissile materials (veto) and measurement of the (n,)/(n,f) ratio.

Capture studies: Capture studies: active canning for active canning for simultaneous (n,simultaneous (n,) & (n,f) measurements) & (n,f) measurements

n_TOF-Ph2

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n_TOF-Ph2

Fission studiesFission studies

n_TOF-Ph2

45 degrees

p’

n

"Thin" E detector

E detector

235U

proton containing target (polyethylene)

fission fragmentsdetector

"Thick" E/Low E detector

104 105 106 107 108

1E-3

0.01

0.1

Count rate protons

235

U

Counts

En, eV

BeamBeam capture mode (2 mm capture mode (2 mm ØØ))

Scattering angleScattering angle 3030°°

Target thicknessTarget thickness 250 250 g/cmg/cm22

Detector radiusDetector radius 20 mm20 mm

Target-to-detector distanceTarget-to-detector distance 250 mm250 mm

Fission studies Fission studies absolute absolute 235235U(n,f) cross section from (n,p) U(n,f) cross section from (n,p) scatteringscattering

(n,p) larger or comparable up to 100 MeV

H235U 0.01 1 100 Neutron energy [MeV]

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n_TOF-Ph2

Fission studies Fission studies FF distributions in vibrational resonancesFF distributions in vibrational resonances

Neutron beam

Position-sensitivedetector

Time-tag detector

Sample

Vacuum chamber

Principles:Principles:

• Time-tag detector for the “start” signal• Masses (kinetic energies) of FF from position-sensitive detectors (MICROMEGAS or semiconductors)

Principles:Principles:

• Time-tag detector for the “start” signal• Masses (kinetic energies) of FF from position-sensitive detectors (MICROMEGAS or semiconductors)

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n_TOF-Ph2

Fission studies Fission studies cross sections with PPAC detectors: present cross sections with PPAC detectors: present setup setup

Measurements:Measurements:

• 231231Pa(n,f) Pa(n,f) • Fission fragments angular distributions (45Fission fragments angular distributions (45°° tilted targets) tilted targets) for for 232232Th, Th, 238238U and other low-activity actinidesU and other low-activity actinides

EAR-EAR-22 boost: boost:• measurements of measurements of 241,243241,243Am (in class-A lab)Am (in class-A lab)• measurements of measurements of 241241Pu and Pu and 244244Cm (in class-A lab)Cm (in class-A lab)


• 231231Pa(n,f) Pa(n,f) • Fission fragments angular distributions (45Fission fragments angular distributions (45°° tilted targets) tilted targets) for for 232232Th, Th, 238238U and other low-activity actinidesU and other low-activity actinides

EAR-EAR-22 boost: boost:• measurements of measurements of 241,243241,243Am (in class-A lab)Am (in class-A lab)• measurements of measurements of 241241Pu and Pu and 244244Cm (in class-A lab)Cm (in class-A lab)

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n_TOF-Ph2

Fission studies Fission studies with twin ionization chamber with twin ionization chamber


• FF yields: mass & charge FF yields: mass & charge • Test measurement with Test measurement with 235235U then measurements of other MAU then measurements of other MA


• FF yields: mass & charge FF yields: mass & charge • Test measurement with Test measurement with 235235U then measurements of other MAU then measurements of other MA

Twin ionization detector with measurement ofboth FF (PPAC principle)

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n_TOF-Ph2

1.1. CIC: compensated ion chamber CIC: compensated ion chamber already tested at n_TOFalready tested at n_TOF

For n_TOF-Ph2:

• four chambers in the same volume for multi-sample measurements


• 147147Sm(n,Sm(n,aa) (tune up experiment)) (tune up experiment)• 66LiF target for calibrationLiF target for calibration

EAR-EAR-22 boost: boost:• approx 100 times the ORELA count rate approx 100 times the ORELA count rate expectedexpected• 6767Zn and Zn and 9999Ru (n,Ru (n,aa) measurements) measurements


• 147147Sm(n,Sm(n,aa) (tune up experiment)) (tune up experiment)• 66LiF target for calibrationLiF target for calibration

EAR-EAR-22 boost: boost:• approx 100 times the ORELA count rate approx 100 times the ORELA count rate expectedexpected• 6767Zn and Zn and 9999Ru (n,Ru (n,aa) measurements) measurements

(n,p), (n,(n,p), (n,aa) & (n,lcp) ) & (n,lcp) measurementsmeasurements <<<<

n_TOF-Ph2

2.2. MICROMEGAS MICROMEGAS already used for measurements of nuclear recoils at n_TOFalready used for measurements of nuclear recoils at n_TOF

For n_TOF-Ph2:

• converter replaced by sample

• expected count rate: 1 reaction/pulse (=200 mb, Ø=5cm, 1m thick)

(n,p), (n,(n,p), (n,aa) & (n,lcp) ) & (n,lcp) measurementsmeasurements <<<<

n_TOF-Ph2

(n,p), (n,(n,p), (n,aa) & (n,lcp) ) & (n,lcp) measurementsmeasurements

3.3. Scattering chambers with Scattering chambers with E-E or E-E or E-E-E-E telescopes E-E telescopes


• 5656Fe and Fe and 208208Pb (tune up experiment)Pb (tune up experiment)• Al, V, Cr, Zr, Th, and Al, V, Cr, Zr, Th, and 238238UU• a few x 10a few x 1018 18 protons/sample in fission modeprotons/sample in fission mode


• 5656Fe and Fe and 208208Pb (tune up experiment)Pb (tune up experiment)• Al, V, Cr, Zr, Th, and Al, V, Cr, Zr, Th, and 238238UU• a few x 10a few x 1018 18 protons/sample in fission modeprotons/sample in fission mode

Setup: in parallel with fission detectors

production cross sections (En) for (n,xc)

c = p, a, d

differential cross sections d/d, d/dE

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n_TOF-Ph2

Neutron scattering reactionsNeutron scattering reactions

N e u tro n b e a m

D ta rg e t2

P ro to n d e te c to r

N e u tro n d e te c to r

5 m

3 4 º

8 0 º

4 6 c

m

D 3

D 4

Neutron incident energy 30 – 75 MeV in 2.5 MeV bins

Kiematic locus of the n + 2H n + p + n reaction for:En = 50 MeVΘn = 20º, Φn = 0ºΘp = 50º, Φp = 180º

Direct n + n scattering experiment not feasible! Direct n + n scattering experiment not feasible!

Alternatively, interaction of two neutrons in the final Alternatively, interaction of two neutrons in the final state of a nuclear reaction. Examples of such state of a nuclear reaction. Examples of such reactions are:reactions are:

++ + + 22H H n + n + n + n +

n + n + 22H H n + n + p n + n + p

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n_TOF-Ph2

<< back

237237Np(n,Np(n,) at n_TOF) at n_TOF


< back

Preliminary

237237Np(n,Np(n,) at LANSCE) at LANSCE

Source: J Ullman, n_BANT workshop, CERN, March 2005

(Analysis byE.I. Esch andR. Reifarth)

< back

NNuclear waste: TRU uclear waste: TRU (1000 MW(1000 MWee LWR)LWR)

239Pu: 125 Kg/yr

237Np: 16 Kg/yr

241Am:11.6 Kg/yr 243Am: 4.8 Kg/yr

244Cm 1.5 Kg/yr

LLFP

LLFP 76.2 Kg/yr

source: Actinide and Fission Product Partitioning and Transmutation – NEA (1999)

<< back<< back

FFast neutrons!ast neutrons!

source: C Rubbia (2002)

<< back<< back

Neutron cross sections data Neutron cross sections data are needed!are needed!


243Am(n,f)

source: n_TOF Collaboration (fission proposal)

<< back<< back

www.cern.ch/n_TOF

[email protected]

neutrons

56Fe 91.72

57Fe 2.2

58Fe 0.28

Fe

Co

60Ni 26.223

59Co100

59Fe 44.503 d

60Fe 1.5 106 a

60Co5.272 a

61Co1.65 h

61Ni 1.140

62Ni 3.634

Ni 63Ni 100 a

64Ni 0.926

58Co70.86 d

62Cu9.74 m

63Cu69.17

64Cu 12.7 h

61Fe 6 m

Cu

[email protected]

56Fe 91.72

57Fe 2.2

58Fe 0.28

Fe

Co

60Ni 26.223

59Co100

59Fe 44.503 d

60Fe 1.5 106 a

60Co5.272 a

61Co1.65 h

61Ni 1.140

62Ni 3.634

Ni 63Ni 100 a

64Ni 0.926

58Co70.86 d

62Cu9.74 m

63Cu69.17

64Cu 12.7 h

61Fe 6 m

Cu

[email protected]

The canonical s-process

direct correlation between direct correlation between

neutron capture cross section neutron capture cross section

and abundance: and abundance:

(n,(n,) ) ·· N = const. N = const.

NNucleosynthesis: the ucleosynthesis: the ss--process process

<< back<< back

NNucleosynthesis: ucleosynthesis: the s-process &the s-process &the the rr-process residuals-process residuals

NNrr = N= Nsolarsolar - N - NssNNrr = N= Nsolarsolar - N - Nss

<< back<< back

n_TOF-Ph2

<< back<< back

Documents

Future Physics and Detectors at n _TOF