Measurements of cross-sections of neutron threshold reactions and their usage in high energy neutron measurements

Measurements of cross-sections of neutron threshold reactions and their usage in high energy neutron measurements

Ondřej Svoboda

• Nuclear Physics Institute, Academy of Sciences of Czech Republic• Department of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague

OutlineOutline

• Motivation - Energy plus Transmutation Motivation - Energy plus Transmutation projectproject

• Cross-section measurementsCross-section measurements• TSL Uppsala experimentTSL Uppsala experiment• Experiments on Cyclotron in ŘežExperiments on Cyclotron in Řež• ConclusionConclusion

- Motivation:E+T project

- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež

- Conclusion

Motivation - Energy plus TransmutationMotivation - Energy plus Transmutation

• Main aim of the E+T - study of transmutation of Main aim of the E+T - study of transmutation of FP and HA by spallation neutronsFP and HA by spallation neutrons

• We are involved in the project for 10 yearsWe are involved in the project for 10 years• Our tasks: Our tasks:

study of neutron production in thick, heavy study of neutron production in thick, heavy target with fissionable blanket irradiated by target with fissionable blanket irradiated by light ions in GeV rangelight ions in GeV range

perform relevant Monte-Carlo simulationsperform relevant Monte-Carlo simulations make comparisons between experimental make comparisons between experimental

data and simulationsdata and simulations

- Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux

- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež

- Conclusion

Energy plus Transmutation - setupEnergy plus Transmutation - setup- Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux

- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež

- Conclusion

Detection of high energy neutronsDetection of high energy neutrons

Al Au Bi

Co In

Ta

ReactionReactionEE threshthresh

[MeV][MeV]Half-lifeHalf-life

197197Au (n,2n) Au (n,2n) 196196AuAu 8.18.1 6.183 d6.183 d

197197Au (n,3n) Au (n,3n) 195195AuAu 14.814.8   186.1 d186.1 d

197197Au (n,4n) Au (n,4n) 194194AuAu 23.223.2 38.02 h38.02 h

197197Au (n,5n) Au (n,5n) 193193AuAu 30.230.2 17.65 h17.65 h

197197Au (n,6n) Au (n,6n) 192192AuAu 38.938.9 4.94 h4.94 h

197197Au (n,7n) Au (n,7n) 191191AuAu 45.745.7 3.18 h3.18 h

- Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux

- Cross - section

measurements- TSL Uppsala- Cyclotron Řež

- Conclusion

Activation-detector Activation-detector eevaluationvaluation

- decay during cooling, decay during cooling, irradiationirradiation

- unequable unequable irradiationirradiation

- coincidences coincidences

- non point-like non point-like emittersemitters

- detector dead timedetector dead time

- detector efficiencydetector efficiency

- self-absorptionself-absorption

- Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux

- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež

- Conclusion

)()(

)(

11

1

)(

0

irrreal tirr

t

t

foillive

real

areaP

irrabspyield e

t

e

e

mt

t

CCoiEI

CCSN

Yield to neutron flux problemYield to neutron flux problem

• To find the Φ(E) a Fredholm equation must be solved:To find the Φ(E) a Fredholm equation must be solved:- Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux

- Cross - section measurements- TSL Uppsala- Cyclotron Řež

- Conclusion

dEEENbeam

thresh

E

E

yield )()(

We would like to know!We would like to know! (Up to know only MCNPX simulation)(Up to know only MCNPX simulation)

Not known for most of the Not known for most of the observed isotopes!observed isotopes!

MeasuredMeasured

197Au(n,2n)196Au

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40 50Neutron energy [MeV]

Cro

ss-s

ectio

n [b

arn]

EXFORENDF

197Au(n,4n)194Au

0.0

0.5

1.0

1.5

2.0

0 10 20 30 40 50Neutron energy [MeV]

EXFORENDF

Requirements for Requirements for -measurements by activation method: -measurements by activation method:

- high energy neutron source with good intensityhigh energy neutron source with good intensity

- monoenergetic (quasi/monoenergetic) neutrons or well known monoenergetic (quasi/monoenergetic) neutrons or well known spectrum spectrum

- pure monoisotopic samples pure monoisotopic samples

- good spectroscopgood spectroscopicic equipment – equipment – and X-rays detectorsand X-rays detectors

- knowledge about the corrections on beam, self-absorption, knowledge about the corrections on beam, self-absorption, non-point like emitters…non-point like emitters…

Cross-section measurementsCross-section measurements- Motivation:E+T project- Cross - section measurements • Requirements

- TSL Uppsala- Cyclotron Řež

- Conclusion

Then we can calculate NThen we can calculate Nyieldyield and finally : and finally :

An

yield

NN

ASN

Evaluation process is the same Evaluation process is the same as as shown before: shown before: Irradiation Irradiation HPGe HPGe Deimos Deimos Corrections Corrections YieldYield

Cross-sectionsCross-sections

TSL UppsalaTSL Uppsala- Motivation:E+T project- Cross - section measurements

- TSL Uppsala • Introduction

• Experiment - Cyclotron Řež

- Conclusion

- Protons on Li target Protons on Li target or spallation sourceor spallation source

- Neutrons with Neutrons with energies 11-174 MeVenergies 11-174 MeV

- Well known beam Well known beam and nand neutr.eutr. spectrum spectrum

June 2008, June 2008, supported by supported by

EFNUDAT programEFNUDAT program

1E0

1E2

1E4

1E6

1E8

1E-7 1E-5 1E-3 1E-1 1E+1 1E+3Neutron Energy [MeV]

Neu

tro

n f

lux

den

sity

[1/

(cm

2.s)

]

spallation source at JINR

quasi-monoenergetic source at TSL102

104

108

106

0 10-7 10-3 10-5

10-1 101 103

TSL Uppsala experiments – June 2008TSL Uppsala experiments – June 2008- Motivation:E+T project- Cross - section measurements

- TSL Uppsala • Introduction • Experiment

- Cyclotron Řež

- Conclusion

- 3 irradiations on the Li target – 25- 3 irradiations on the Li target – 25,, 50 50,, and and 100100 MeV p+ MeV p+

- one irradiation on the ANITA spallation target – 1- one irradiation on the ANITA spallation target – 1880 MeV p+0 MeV p+

- 8 hours each, than always one day of spectroscopic - 8 hours each, than always one day of spectroscopic measurementsmeasurements

Au, Al, Bi, In, Ta, I samplesAu, Al, Bi, In, Ta, I samples

Finished yields evaluation, waiting on the Finished yields evaluation, waiting on the beam data...completed after summer breakbeam data...completed after summer break

Cyclotron ŘežCyclotron Řež- Motivation:E+T project- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež • Introduction • Experiments

- Conclusion

-Up to now 2 Up to now 2 experiments: experiments: 20 and 25 MeV20 and 25 MeV

- Au, Al, Bi, In, Ta, I, Au, Al, Bi, In, Ta, I, Ni, Fe, Mg, ZnNi, Fe, Mg, Zn

-next irradiationnext irradiationss planed on October planed on October 20082008

- Protons on Li targetProtons on Li target

-Neutrons with Neutrons with energies 10-37 MeVenergies 10-37 MeV

- Good intensitiesGood intensities

- Well equipped Well equipped spectroscopy spectroscopy laboratory (NSD-NPI)laboratory (NSD-NPI)

0E+00

4E+14

8E+14

1E+15

2E+15

0 10 20 30 40Neutron energy [MeV]

20 MeV25 MeV30 MeV35 MeV40 MeV

.1014

.1014

0

n [

1/s

r M

eV

C]

.1015

.1015

0

0.25

0.5

0.75

1

1.25

1.5

20 25 30 35 40Energy [MeV]

Cro

ss-s

ecti

on

[b

arn

]

EXFOR dataOur value - Řež

Cyclotron Řež experimentsCyclotron Řež experiments

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40Energy [MeV]

Cro

ss-s

ecti

on

[b

arn

]EXFOR dataOur value - Řež

- Motivation:E+T project- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež • Introduction • Experiments

- Conclusion

Tentative data!Tentative data!

Evaluation not yet Evaluation not yet ready…ready…

An

yield

NN

ASN

Number of Number of neutrons in peakneutrons in peak

ConclusionConclusion

– Uppsala and Řež cross-section measurements Uppsala and Řež cross-section measurements covered wide spectrum of energiescovered wide spectrum of energies

– Preliminary results shows we are close to known Preliminary results shows we are close to known cross-section valuescross-section values

– Near future – next measurements at Řež Near future – next measurements at Řež – Farther future – next measurements at UppsalaFarther future – next measurements at Uppsala

– – application of the results application of the results on the E+T on the E+T experiments experiments

– – publish the measured publish the measured cross-sections cross-sections with respect to be with respect to be involved in the involved in the EXFOR EXFOR library if possiblelibrary if possible

Thank you for your attention..

- Motivation:E+T project- Cross - section measurements

- TSL Uppsala

- Cyclotron Řež

- Conclusion