Fission of Heavy Nuclei With Emission of Long-Range Α Particles

Abstract

The emission of positronium negative ions from Cs deposited W(100) surfaces has been studied. A dramatic change in the emission efficiency was observed upon coating a W(100) surface with Cs. The conversion efficiency (the fraction of incident slow positrons yielding the ions) of the W(100) target with a 2.2 × 10 14 atoms cm −2 Cs coverage, measured over a time interval of 3 × 10 3 s immediately after deposition, was found to be 1.25%, which is two orders of magnitude higher than that obtained for the clean, uncoated W(100) surface and 45 times greater than the highest efficiency reported thus far.

Three Fragment Fission

“…I t has been known for many years that the angular distribution of the highest energy fission ex particles is broader than that for moderate energy ex particles (64) . This relation has been confirmed in a number of studies (18) including some at intermediate energy (e.g.…”

α-accompanied cold ternary fission ofPu238–244isotopes in equatorial and collinear configuration

“…The driving potential is calculated for the ternary fragmentation of 238 Pu, treating 4 He as the light charged particle (LCP) and is plotted as function of fragment mass number A 1 as shown in figure 2. The minima occur in the cold valley is for A 1 = 4 He, 10 Be, 14 C, 22 O, 26 Ne, 30 Mg, 34 Si, 40…”

“…The alpha accompanied ternary fission of [238][239][240][241][242][243][244] Pu isotopes has been studied with fragments in collinear configuration, in which the light charged particle 4 He lies in between the other two fission fragments. The driving potential is calculated for all possible fragment combinations of [238][239][240][241][242][243][244] Pu isotopes and has been plotted as a function of mass numbers A 1 and is shown in figure 7.…”

“…[1]), where the authors have computed the number of alpha particles emitted in coincidence with the fission of 235 U and 239 Pu isotopes. Later Perfilov et al [2][3][4] have studied the energy spectra of alpha particles for ternary fission of different isotopes of uranium, plutonium and curium isotopes and in 1964 Malkin et al [5] have studied the spectrum of long range alpha particle from the spontaneous fission of 244 Cm isotope and obtained the most probable energy of the alpha particle as 15.8MeV. The angular distributions and the energy distributions of long range alpha particles emitted from the spontaneous ternary fission of 252 Cf isotope have been studied using the statistical theory of nuclear fission by Vitta [6] and the multiparameter measurements are performed by Theobald et al, in order to compute the kinetic energies and relative angles of the three particles emitted in the ternary fission process [7].…”

“…Later in the beginning of the twenty-first century Florescu et al [16] calculated the pre-formation amplitude for 4 He and 10 Be clusters formed in the ternary fission of 252 Cf. In terms of spheroidal co-ordinates, Delion et al [17] studied the dynamics of cold ternary fission of 252 Cf isotope with light charged particle as 4 He and 10 Be. The clusters heavier than alpha particles like 5 He, 7 He and 8 Li that formed during the spontaneous ternary fission of 252 Cf has been studied by Kopatch et al [18].…”