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Determination of experimental cross-sections by activation method

This study details the determination of experimental cross sections through the activation method, utilizing the DEIMOS32 system for gamma spectrum analysis. It involves measuring radioactive samples activated in a cyclotron under various configurations. The analysis compares gamma line intensities and calculates yields and uncertainties for different isotopes produced via neutron interactions. Statistical methods are used to enhance precision in cross-section calculations, providing relevant results for isotopes such as 197Au, 196Au, and 194Au.

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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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