[en] The increasing demands on irradiation conditions require more precise knowledge of the neutron spectrum. The spectrum on the horizontal channel with epithermal neutron beam at the LVR-15 light water research reactor is measured by activation detectors (Au, In, Sc, W, La, Mn, Cu, and Ni). Especially gold is often used as a reference detector thanks to its suitable physical and chemical characteristic. Exploration of two types of the Au detectors (the pure Au (100 %) detector and the Au (1 %) detector (Al alloy)) is described in this article. Three experiments on the epithermal beam were realized, one with the bare Au detectors, one with the cadmium covered Au detectors and one with a polyamide (PA) filter (moderator). Cadmium ratios were determined for the Au (100 %) and the Au (1 %) detectors. Although a method of activation detectors has been used for a long time, comparative measurements for each irradiation position are considered substantial requirement for achieving high accuracy of determination of neutron spectrum. It is also proposed to calculate the self-shielding factors and the cadmium ratios by the Monte Carlo neutron transport code (MCNP) and to compare the calculated results with the experimental measurements. (authors)