Production of unknown neutron-rich transuranium isotopes ^245–249Np, ^248–251Pu, ^248–254Am, and ^252–254Cm in multinucleon transfer reactions

Abstract

The production cross sections of unknown neutron-rich transuranium isotopes of elements Np, Pu, Am and Cm are investigated in multinucleon transfer reactions based on the dinuclear system model with GEMINI code. The influence of the incident energy on the production of neutron-rich transuranium nuclei in actinideactinide collisions is studied. The calculation results show that the final isotopic production cross sections are larger at 1.06-1.10 Vcont than at other energies. Considering the high fissility of transuranium nuclides, 1.06 Vcont is chosen as the optimal incident energy. The N/Z ratio equilibration mechanism in the nucleon transfer process is also studied in this work. The larger difference of N/Z ratio between projectile and target corresponds to larger neutron diffusion during the nucleon exchange process. The 238U beam with high N/Z ratio and neutron-rich actinide targets are good selections to produce neutron-rich transuranium nuclides. The production cross sections of unknown neutron-rich transuranium isotopes 245-249Np, 248-251Pu, 248-254Am, and 252-254Cm are predicted in 238U-induced actinide-based (249Bk, 249Cf, and 252Cf) multinucleon transfer reactions. It is found that a large number of these unknown neutron-rich transuranium nuclei could be generated at the level of nb to µb in the reactions 238U+249Bk and 238U+252Cf. Our research indicates that the reaction 238U+249Bk is a suitable projectile-target combination in the current experimental conditions and the reaction 238U+252Cf could be a promising candidate to produce unknown neutron-rich transuranium nuclides in case that the 252Cf target were to be achieved in the future.

Simultaneous Determination of Transuranium Radionuclides for Nuclear Forensics by Compact Accelerator Mass Spectrometry

“…Radionuclides of transuranium in different samples such as swipes, particles, and bulk collected from suspected subjects are often determined to compare their isotopic fingerprint (isotopic ratios) with the relevant information in uranium ore, nuclear fuel, and spent nuclear fuel of specific sources for nuclear forensic investigation. TRU standard solutions ( 241 Pu, 241 Am, 244 Cm) are usually produced by irradiation of target materials (radionuclide) in a high-flux isotope reactor through the transmutation reaction of a series of neutron captures and β decays. , Other impurity radionuclides formed in the irradiation might have remained in the production of TRUs even if separation and purification processes have been conducted. In this work, three simulated forensic samples were prepared by spiking a known amount of a commercially available standard solution of 241 Am, 241 Pu, and 244 Cm (50–100 fg) into 100 mL of water, respectively; all isotopes of Pu, Np, Am, and Cm were determined using the developed methods.…”

Rules of thumb for synthesizing superheavy elements

“…A memory of the entrance channel effects, such as the Coulomb interaction parameter (z), compound nucleus (CN) fissility (χ CN ), effective entrance channel fissility (χ eff ), mean fissility (χ m ), charge (α) and mass asymmetry (η), is often retained in the heavy-ion reactions [10][11][12][13][14], especially, producing CN of A ≈ 220 [15], A ≈ 230 [16], actinide [17] and the superheavy regime [18]. The entrance channel dynamics for cold fusion reactions were studied in detail about two decades ago [19].…”

Production mechanism and prediction cross sections of unknown neutron-rich 263–265,267–269Lr isotopes in multinucleon transfer reactions based on the dinuclear system model

“…Various theoretical models have been developed to describe the MNT process in low-energy heavy-ion collisions. The semiclassical models, such as the dinuclear system (DNS) model [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66], the Langevin equations [67][68][69][70], the GRAZING model [40,[71][72][73][74][75], and the complex Wentzel-Kramers-Brillouin model [76][77][78]. The microscopic dynamics models, such as the improved quantum molecular dynamics (ImQMD) model [79][80][81][82][83][84] and the time-dependent Hartree-Fock model [85][86][87][88][89][90][91][92][93][94][95][96][97]…”