Nuclear Physics Institute Academy of Sciences of Czech

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

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

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 • 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 Ge. V range § perform relevant Monte-Carlo simulations § make comparisons between experimental data and simulations

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

Detection of high energy neutrons - Motivation: E+T project • Introduction • Setup • Detection of neutrons • Evaluation • Yield to neutron flux - Cross - section Al measurements - TSL Uppsala - Cyclotron Řež Reaction E thresh [Me. V] Half-life 197 Au (n, 2 n) 196 Au 8. 1 6. 183 d 197 Au (n, 3 n) 195 Au 14. 8 186. 1 d 197 Au (n, 4 n) 194 Au 23. 2 38. 02 h 197 Au (n, 5 n) 193 Au 30. 2 17. 65 h 197 Au (n, 6 n) 192 Au 38. 9 4. 94 h 197 Au (n, 7 n) 191 Au 45. 7 3. 18 h - Conclusion Au Bi Co In Ta

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

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! Not known for most of the (Up to know only MCNPX simulation) observed isotopes!

Cross-section measurements - Motivation: E+T project - Cross - section measurements • Requirements - TSL Uppsala - Cyclotron Řež Requirements for s-measurements by activation method: - Conclusion - pure monoisotopic samples - high energy neutron source with good intensity - monoenergetic (quasi/monoenergetic) neutrons or well known spectrum - 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 : Evaluation process is the same as shown before: Irradiation HPGe Deimos Corrections Yield Cross-sections

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

TSL Uppsala experiments – June 2008 - Motivation: E+T project - Cross - section measurements - TSL Uppsala • Introduction • Experiment - 3 irradiations on the Li target – 25, 50, and 100 Me. V p+ - one irradiation on the ANITA spallation target – 180 Me. V p+ - 8 hours each, than always one day of spectroscopic measurements - Cyclotron Řež - Conclusion Au, Al, Bi, In, Ta, I samples Finished yields evaluation, waiting on the beam data. . . completed after summer break

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 Me. V - Good intensities - Well equipped spectroscopy laboratory (NSD-NPI) -Up to now 2 experiments: 20 and 25 Me. V - Au, Al, Bi, In, Ta, I, Ni, Fe, Mg, Zn -next irradiations planed on October 2008

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

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. .