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Cross section measurements of neutron induced reactions on isotopes of natural Ge and Hf have been carried out at the 5.5 MV Tandem accelerator of the NCSR “Demokritos” in Athens, Greece, using the activation technique. The measurements have been performed at neutron incident energies 8.8, 9.6, 10.6, 11.1, 11.4 MeV for the case of Ge and at 8.8, 9.6, 11.1, 11.4 MeV for the Hf one. In all cases the target material was Ge and HfO2 powder of high purity.

The measurement of the cross section of the reaction 241Am (n, 2n)240Am, has been performed, for the first time at neutron energies from 8.8, to 11.1MeV, by the activation method. The neutron beam was produced at the TANDEM accelerator of NCSR “Demokritos”, by the 2H (d,n)3 He reaction, using a deuterium gas target. During the 5‐day long irradiation, the neutron beam fluctuations were monitored in 100 sec intervals by a BF3 counter connected with a multi‐scaling unit. The radioactive target consisted of a 37GBq 241Am source enclosed in a Pb container. A natural Au foil, a 27Al foil and a 93Nb foil were used as reference materials for the neutron flux determination. After the end of the irradiation the activity induced at the target and the reference foils, was measured off‐line by a 56 % HPGe detector.

In the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR “Demokritos” monoenergetic neutron beams have been used in the energy range 7–11.5 MeV, produced via the 2H(d,n) reaction. The flux variation of the neutron beam is monitored by using a BF3 detector, while an investigation of the energy dependence of the neutron fluence is carried out via the multiple foil activation technique. The 232Th(n,2n)231Th and 241Am(n,2n)240Am as well as (n,2n), (n,p) and (n,α) reactions on natural Ge and Hf isotopes, have been investigated from threshold up to 11.5 MeV, by using the activation method. The cross section values have been determined relative to the 197Au(n,2n)196Au, 27Al(n,α)24Na and 93Nb(n,2n) reference reaction cross sections.

The neutron facility at the 5.5 MV Tandem T11/25 Accelerator of NCSR “Demokritos” will be presented. The facility can deliver monoenergetic neutron beams in the energy range 120–650 keV, 4–11.5 MeV and 16–20.5 MeV via the 7Li(p,n), 2H(d,n) and 3H(d,n) reactions, respectively. The corresponding beam energies obtained from the accelerator, are 1.92–2.37 MeV protons, 0.8–9.6 MeV deuterons and 0.8–3.7 MeV deuterons, for the three reactions, respectively. Experimental results for neutron energies up to 11.5 MeV will be presented for the 232Th(n,2n)231Th reaction. In context with the CERN n‐TOF collaboration, the cross section of this reaction has been measured relative to the 56Fe(n,p)56Mn and 27Al(n,α)24Na reaction cross sections, by using the activation method. In addition to the experimental work, theoretical Statistical model calculations have also been performed using the computer code STAPRE/F. The results are being compared to the experimental data.