Cross sections for formation of radon and mercury isotopes in complete fusion reaction with heavy ions 36, 40Ar and 40, 48Ca / Regularities of helium swelling in ferrite alloys

Seminars

Flerov Laboratory of Nuclear Reactions


Date and Time: Thursday, 25 May 2023, at 3:30 PM

Venue: Conference Hall, Flerov Laboratory of Nuclear Reactions

  1. Seminar topic: “Cross sections for the formation of radon and mercury isotopes in complete fusion reaction with heavy ions 36, 40Ar and 40, 48Ca”

    Speaker: Elena Chernysheva (in connection with the election for the position of a researcher)

    Abstract:

    Absolute cross sections of xn-evaporating channels for 144Sm(40Ar, xn)184 – xHg, 148Sm(36Ar, xn)184 – xHg, 144Nd(40Ca, xn)184 – xHg, 142Nd(48Ca, xn)190 – xHg and 166Er(40Ar, xn)206 – xRn complete fusion reactions were measured using a modified mobile absorber method. Deconvolution method was used to take into account the influence of the energy spread of the incident heavy ion beam on the evaporating residue excitation functions. The measured excitation functions were compared with theoretical calculations of the coupled channel model.


  2. Seminar topic: “Regularities of helium swelling in ferrite alloys”

    Speaker: Nguen Van Tiep (in connection with the election for the position of junior researcher)

    Abstract:

    Transmission electron microscopy (TEM) method was used to study the regularities of helium swelling in three different types of ferrite class alloys: ordinary steel AISI410S and two experimental dispersion-strenthened (DSO) EP450 and Cr16 alloys. All steel samples were uniformly alloyed with helium ([He] = 0.2 and 1 at.%) at room temperature with the following annealing (Tanneal=1073К – 30 min.). TEM studies showed various patterns of helium porosity development: bimodal bubble distribution in AISI410S and Cr16DSO samples, and uniform grain volume growth of bubbles in EP450DSO samples. It’s shown that bubble volume grow according to the bubble migration mechanism and merging regardless of material type. Gas bubble volume increases approximately linearly with the increase of their diameters. It’s been proven that bubble surface area related to the number of gas atoms in them doesn’t change in the process of their thermal growth, and for helium bubbles in ferrite lies in the range from 1×104 to 2×104 m2/mol.

    (based on the candidate’s dissertation)