Improved Activation Measurements of (n, γ) Cross Section for 14.6-MeV Neutrons

Activation radiative-capture cross sections of 14.6-MeV neutrons in ²⁷Al, ⁵⁰Ti, ⁵¹V, ¹⁰³Rh, ¹²⁷I, and ¹³⁹La have been measured to check and extend to other nuclei recent improved activation measurements. The measured activities strongly depend on the target-head material, on the tritium target backing and on the sample thickness, whose influence is taken into account in the present experiment. The results of the improved activation measurements agree with each other and also with (n, γ) cross sections deduced from integration of measured gamma-ray spectra, thus confirming that a large part of earlier activation measurements were in error. Agreement between experiment and theory is obtained with calculations based on the direct and semidirect models.