Activation cross-sections for short-lived reaction products on hafnium isotopes induced by 1 – 20 MeV neutrons

Abstract

Results of new activation cross-section measurements for production of ^178m1Hf (T_1/2 = 4.0 s) and 179m1Hf (T_1/2 = 18.67 s) are presented for the following reactions: ¹⁷⁸Hf(n,n´)^178m1Hf, ¹⁷⁹Hf(n,2n)^178m1Hf, 180Hf(n,3n)178m1Hf, ¹⁷⁹Hf(n,n´)^179m1Hf, and ¹⁸⁰Hf(n,2n)^179m1Hf. The irradiations were carried out at the 7-MV Van de Graaff accelerator at EC-JRC, Geel. Neutrons in the 1-3 MeV energy range were produced via the ³H(p,n)³He reaction. Deuteron beam and a deuterium gas target were used to produce 5 and 6 MeV neutrons. For the production of quasi-monoenergetic neutrons between 16 and 19.5 MeV the 3H(d,n)4He reactions was employed. Both samples with natural composition and isotopic enrichment were employed to differentiate reactions leading to the same product. An automated pneumatic system was used for the sample irradiation, transport and radioactivity measurements. The radioactivity of the samples was determined by standard gamma-spectrometry using HPGe detector. The results obtained in the present work are compared with the data from other authors and TENDL-2017 evaluation.