Joint IAEA-ICTP Workshop on Nuclear Reaction Data for Advanced Reactor Technologies

1. Joint IAEA-ICTP Workshop on Nuclear Reaction Data for Advanced Reactor Technologies Student’s presentation Calculation of correction factors for neutron capture cross section measurements Pham Ngoc Son, Nuclear Research Institute, VAEC, Vietnam

2. Introduction • The average capture cross sections, <a>, at an average neutron spectrum energy can be measured relative to the standard capture cross section of 197Au by activation method: fc: correction factors

3. Introduction • Correction factors must be introduced to take into account: • Multi-scattering of neutron in sample • Self-shielding effect • Resonance capture with neutrons in low energy background region Monte Carlo simulation Exactly estimation of neutron spectrum (unfolding method)

4. Computer programs

5. Computer programs

6. Computer programs 69.2eV 70.4eV Th-232

7. Computer programs Unfolding neutron spectrum of 54keV filtered neutron beam at Dalat Reactor

8. Computer programs Unfolding neutron spectrum of 148.3keV filtered neutron beam at Dalat Reactor

9. Computer programs In a neutron activation experiment, the reaction rate will be measured indirectly, by detection of emitted decay gamma rays from the product nucleus: Can be Measured by using a HPGe Detector The second term accounts for the effect of neutron in background region. The first term of the reaction rate accounts for the effect of neutrons in the primary region of spectrum.

10. Experimental results Results of measured capture cross section for some nuclei

11. Thank you for your attention!