[en] An intense source of ³⁷Ar was produced by the (n, α) reaction on ⁴⁰Ca by irradiating calcium oxide in the fast neutron breeder reactor at Zarechny, Russia. The ³⁷Ar was released from the solid target, sealed into a small source, and was used to irradiate 13 tonnes of gallium metal in the Russian-American gallium solar neutrino experiment SAGE. The initial source strength was 409 ± 2 kCi. The measured production rate of ⁷¹Ge on gallium metal was 11.0^+1.0_-0.9 (stat) ± 0.6 (syst.) atoms per day, which is 0.79^+0.09_-0.10 of the theoretically calculated production rate

[en] The activity of an artificial neutrino source based on ³⁷Ar was measured by a specially developed method of directly counting ³⁷Ar decays in a proportional counter. This source was used to irradiate the target of the SAGE radiochemical gallium-germanium neutrino telescope at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow), whereupon the measurements were performed at the Institute of Reactor Materials (Zarechny, Sverdlovsk oblast, Russia). The method used to prepare gaseous samples for measurements in proportional counters and the counting procedure are described. The measured activity of the ³⁷Ar neutrino source is 405.1 ± 3.7 kCi (corrected for decays that occurred within the period between the instant of activity measurement and the commencement of the irradiation of Ga target at 04:00 Moscow time, 30.04.2004)

[en] In April 2004, a neutrino source was produced by irradiating a 330-kg piece of pressed calcium oxide at the fast-neutron reactor BN-600 (Zarechny, Russia) for six months. The ³⁷Ar isotope was obtained via the (n, α) reaction on ⁴⁰Ca, and ³⁷Ar was extracted from an aqueous solution of nitric acid in which the solid target was dissolved. After that, ³⁷Ar was purified and sealed into a capsule. This source was used to measure the neutrino-capture rate in metalic gallium for neutrinos from ³⁷Ar decay, which have an energy close to that of the main line of solar ⁷Be neutrinos (863 keV). The target of the SAGE Gallium-Germanium Neutrino Telescope was irradiated by using this source at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences). The source activity was measured by several methods during its production, in the course of irradiation, and after its completion. The weighted mean of the activity for six measurements was 409 ± 2 kCi at the beginning of irradiation of the gallium target (04:00 Moscow time, 30.04.2004). The scatter in the activity values obtained by different methods does not exceed 5%

[en] An intense ³⁷Ar source was produced by the (n, α) reaction on ⁴⁰Ca by irradiating 330 kg of calcium oxide in the fast neutron breeder reactor at Zarechny, Russia. The ³⁷Ar was released from the solid target by dissolution in acid, collected from this solution, purified, sealed into a small source, and brought to the Baksan Neutrino Observatory, where it was used to irradiate 13 t of gallium metal in the Russian-American solar neutrino experiment SAGE. Ten exposures of the gallium to the source, whose initial strength was ∼ 409 ± 2kCi, were carried out during the period from April to September 2004. The ⁷¹Ge produced by the reaction ⁷¹Ga(ν_e, e^-)⁷¹Ge was extracted, purified, and counted. The measured production rate was 11.0_-0.9^+1.0 (stat.) ±0.6 (syst.) atoms of ⁷¹Ge/d, which is 0.79_-0.10^+0.09 of the theoretically calculated production rate