Prompt neutrons accompanying the spontaneous fission of 250No.

This paper describes the experiment conducted on the SHELS (Separator for Heavy Element Spectroscopy) separator [1] aimed at studying the properties of spontaneous fission of ²⁵⁰No. A separator detection system consists of a time-of-flight system and SFiNx (Spontaneous Fission, Neutrons and x-rays) detection system [2] is described. The SFiNx detection system consists of an assembly of double-sided Si detectors, around which 116 proportional neutron counters filled with ³He are placed. During experiment, 1366 events of spontaneous fission of ²⁵⁰No were registered. The average number of neutrons per one fission ( v ¯ = 4.24 ± 0.13) and the distribution of neutron multiplicities were obtained, and the half-lives of the ²⁵⁰No were measured for the ground T_1/2 = (3.89 ± 0.17) µs and isomeric states T_1/2 = (39.14 ± 3.34) µs. [ABSTRACT FROM AUTHOR]