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

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Contents Introduction Spectrum analysis with DEIMOS32 Cross-sections calculation Statistical analysis (incertainty calculation) Results

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Introduction My work consists: In analysing gamma spectrums from experiment with DEIMOS32… Experiment = measurement of radioactive sample (activated by activation method in a cyclotron) with different configurations …To get experimental cross-sections

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Spectrum analysis with DEIMOS32 Gamma lines peak analysis with the software DEIMOS 32

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Spectrum analysis with DEIMOS32 We’re able to plan possible reactions and isotopes produced

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Spectrum analysis with DEIMOS32 Comparison between the result tables from DEIMOS 32 analysis and the internet data base (decay data search) on gamma lines to identify the isotopes

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Spectrum analysis with DEIMOS32 4 isotopes found from (n,2n) to (n,4n) reactions and 1 isotope (198Au) found from (n,gamma) reaction.

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Cross-sections calculation Nyield calculation: Peak areaSelf-absorption correction Beam correction Dead time correctionDecay during cooling and measurement γline intensity Detector efficiency Correction for coincidences Square-emitter correction Weight normalization Decay during irradiation

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

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Cross-sections calculation Nyield calculation: Sp: peak area I γ: gamma line intensity (in %) T real & T live: datas from exp. λ: decay constant T irr: irradiation time T 0: beam end – start of measurement

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Cross-sections calculation Cross-section calculation: N n: neutrons number (depends on experiment) m foil: foil mass S: foil size (in cm 2) A: mass number (197 for Au) N A: Avogadro’s number ( 6, {mol -1 })

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Statistical analysis N yield_average calculation for each isotope => to increase the precision: Aerr: incertainty of peak area (data from DEIMOS) So =>

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Statistical analysis N yield_average calculation for each isotope => to increase the precision: Aerr: incertainty of peak area (data from DEIMOS) So =>

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Statistical analysis Finally: With:

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Results 197 Au (n, 2n) 196 Au

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Results 197 Au (n, 4n) 194 Au

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Results 197 Au (n, 2n) 196m2 Au

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Results Comments: Fluctuations are purely systematical N yield-average isn’t depending on the configuration But the difference of N yield-average (calculated for each gamma line and isotope) is bigger than the uncertainty of weighted average. It comes from the systematic uncertainty of efficiency determination.

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Thank you for your attention !!!

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