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Determination of experimental cross-sections by activation method

Determination of experimental cross-sections by activation method. Pierre-Jean Viellenave Tutor : Dr. Vladimir Wagner Nuclear Physics Institute, Academy of Sciences of Czech Republic. Contents. Introduction Spectrum analysis with DEIMOS32 Cross-sections calculation

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Determination of experimental cross-sections by activation method

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  1. Determination of experimentalcross-sections by activation method Pierre-Jean Viellenave Tutor: Dr. Vladimir Wagner Nuclear Physics Institute, Academy of Sciences of Czech Republic

  2. Contents • Introduction • Spectrum analysiswith DEIMOS32 • Cross-sections calculation • Statisticalanalysis (incertaintycalculation) • Results

  3. Introduction • Myworkconsists: • In analysing gamma spectrumsfromexperimentwith DEIMOS32… • Experiment= measurement of radioactive sample (activated by activation method in a cyclotron) withdifferent configurations • …To getexperimental cross-sections

  4. Spectrum analysiswith DEIMOS32 • Gamma linespeakanalysiswith the software DEIMOS 32

  5. Spectrum analysiswith DEIMOS32 • We’re able to plan possible reactions and isotopes produced

  6. Spectrum analysiswith DEIMOS32 • Comparisonbetween the result tables from DEIMOS 32 analysis and the internet data base (decay data search) on gamma linesto identify the isotopes

  7. Spectrum analysiswith DEIMOS32 • 4 isotopes foundfrom (n,2n) to (n,4n) reactions and 1 isotope (198Au) foundfrom (n,gamma) reaction.

  8. Dead time correction Decay during cooling and measurement Peak area Self-absorption correction Beam correction γline intensity Decay during irradiation Weight normalization Detector efficiency Correction for coincidences Square-emitter correction Cross-sections calculation • Nyieldcalculation:

  9. Cross-sections calculation • Detector efficiency (given): Nyield approximation:

  10. Cross-sections calculation • Nyieldcalculation: Sp: peak area Iγ: gammaline intensity (in %) Treal & Tlive: datas from exp. λ: decay constant Tirr: irradiation time T0: beam end – start of measurement

  11. Cross-sections calculation • Cross-section calculation: Nn: neutrons number (depends on experiment) mfoil: foil mass S: foil size (in cm2) A: mass number (197 for Au) NA: Avogadro’s number (6,022.1023 {mol-1})

  12. Statisticalanalysis • N yield_averagecalculation for each isotope => to increase the precision: Aerr: incertainty of peak area (data from DEIMOS) So =>

  13. Statisticalanalysis • N yield_averagecalculation for each isotope => to increase the precision: Aerr: incertainty of peak area (data from DEIMOS) So =>

  14. Statisticalanalysis • Finally: With:

  15. Results 197Au (n, 2n) 196Au

  16. Results 197Au (n, 4n) 194Au

  17. Results 197Au (n, 2n) 196m2Au

  18. Results • Comments: • Fluctuations are purelysystematical • Nyield-averageisn’tdepending on the configuration • But the difference of Nyield-average(calculated for each gamma line and isotope) isbiggerthan the uncertainty of weightedaverage. It comesfrom the systematicuncertainty of efficiencydetermination.

  19. Thankyou for your attention !!!

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