Prompt neutrons accompanying the spontaneous fission of 250^{250}No

International audienceThis 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 T1/2 = (3.89 ± 0.17) µs and isomeric states T1/2 = (39.14 ± 3.34) µs