Measurements of Neutron Threshold Reaction Cross-Sections in High Energy Neutron Measurements

1. Nuclear Physics Institute, Academy of Sciences of Czech Republic • Department of Nuclear Reactors, Faculty of Nuclear Sciences andPhysical Engineering, Czech Technical University in Prague Measurements of cross-sections of neutron threshold reactions and their usage in high energy neutron measurements Ondřej Svoboda

2. Outline - Motivation:E+T project - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion • Motivation - Energy plus Transmutation project • Cross-section measurements • TSL Uppsala experiment • Experiments on Cyclotron in Řež • Conclusion

3. Main aim of the E+T - study of transmutation of FP and HA by spallation neutrons We are involved in the project for 10 years Our tasks: study of neutron production in thick, heavy target with fissionable blanket irradiated by light ions in GeV range perform relevant Monte-Carlo simulations make comparisons between experimental data and simulations Motivation - Energy plus Transmutation - Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion

4. Energy 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

5. Ta Al Au Bi Co In Detection of high energy neutrons - Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion

6. Activation-detector evaluation - Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion • decay during cooling, irradiation • unequable irradiation • coincidences • non point-like emitters • detector dead time • detector efficiency • self-absorption

7. Yield to neutron flux problem - Motivation:E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion • To find the Φ(E) a Fredholm equation must be solved: Measured We would like to know! (Up to know only MCNPX simulation) Not known for most of the observed isotopes!

8. Evaluation process is the same as shown before: Irradiation HPGe Deimos CorrectionsYieldCross-sections Cross-section measurements - Motivation:E+T project - Cross - section measurements • Requirements - TSL Uppsala - Cyclotron Řež - Conclusion • Requirements for s-measurements by activation method: • high energy neutron source with good intensity • monoenergetic (quasi/monoenergetic) neutrons or well known spectrum • pure monoisotopic samples • good spectroscopic equipment – g and X-rays detectors • knowledge about the corrections on beam, self-absorption, non-point like emitters… Then we can calculate Nyield and finally :

9. TSL Uppsala • Protons on Li target or spallation source • Neutrons with energies 11-174 MeV • Well known beam and neutr. spectrum - Motivation:E+T project - Cross - section measurements - TSL Uppsala • Introduction • Experiment - Cyclotron Řež - Conclusion June 2008, supported by EFNUDAT program

10. TSL 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, 50, and 100 MeV p+ - one irradiation on the ANITA spallation target – 180 MeV p+ - 8 hours each, than always one day of spectroscopic measurements Au, Al, Bi, In, Ta, I samples Finished yields evaluation, waiting on the beam data...completed after summer break

11. Cyclotron Řež - Motivation:E+T project - Cross - section measurements - TSL Uppsala - Cyclotron Řež •Introduction • Experiments - Conclusion • Protons on Li target • Neutrons with energies 10-37 MeV • Good intensities • Well equipped spectroscopy laboratory (NSD-NPI) • Up to now 2 experiments: 20 and 25 MeV • Au, Al, Bi, In, Ta, I, Ni, Fe, Mg, Zn • next irradiations planed on October 2008

12. Cyclotron Řež experiments - Motivation:E+T project - Cross - section measurements - TSL Uppsala - Cyclotron Řež •Introduction • Experiments - Conclusion Number of neutrons in peak Tentative data! Evaluation not yet ready…

13. Conclusion - Motivation:E+T project - Cross - section measurements - TSL Uppsala - Cyclotron Řež - Conclusion • Uppsala and Řež cross-section measurements covered wide spectrum of energies • Preliminary results shows we are close to known cross-section values • Near future – next measurements at Řež • Farther future – next measurements at Uppsala – application of the results on the E+T experiments – publish the measured cross-sections with respect to be involved in the EXFOR library if possible Thank you for your attention..