²⁴⁶Fm spontaneous fission

SHELS separator experiment aimed at studying ²⁴⁶Fm spontaneous fission was completed at FLNR JINR. The isotope was synthesized in the complete fusion reaction of ⁴⁰Ar beam ions with ²⁰⁸Pb target nuclei.

The neutron yields of ²⁴⁶Fm spontaneous fission (^–ν = 3.79±0.30, σ²_ν = 2.1) were got using SFiNx detector system. The multiplicity distribution of emitted neutrons was restored by Tikhonov method of statistical regularization (^–ν_r =3.79 ±0.20, σ²_νr = 2.8). This isotope spontaneous fission branching ratio (bSF = 0.061 ± 0.005) and half-life (T1/2 = 1.50 +0.08-0.07 с) were determined as well.

This work experimental data were compared with the predictions of the improved scission point model.

For ²⁵²Cf, ²⁴⁸Cm and ²⁴⁶Fm nuclei an excellent convergence was observed in the average number of neutrons per fission act but neutron multiplicity distribution form for ²⁴⁶Fm is on the contrary very poor. So we need more exact control of the nonequilibrium processes. We work in this direction now.

The results were declared in JINR Publishing Department preprint of A.Isaev, FLNR j.r.s. et al. authorship. The results of the experiment were published in European Physical Journal A.

This work got RFBR and JINR grants. One of the coauthors (T.M.Shneidman) was supported by Kazan Federal University.