Preferential polar emission in the alpha decay of deformed Cf249 and E253

Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters*

“…The constant internal amplitudes give good results to the observed anisotropies in the favoured alpha decay of four odd-even deformed actinide nuclei as reported in [8]. From the experimental point of view, a number of important observations of remarkably pronounced preferential alpha emission in oriented odd-A alpha emitters have been reported by Hanauer et al [9], Navarro et al [10], Soinski et al [11], Dilmanian et al [12], and more recently by Soinski and Shirley [13], Wouters et al [14], and Schuurmans et al [15]. This latter work showed for the first time that anisotropic alpha emission in favoured decays is mainly determined by the structure (shell effects) of the decaying nucleus, not being necessarily related to deformation.…”

“…As a result the equivalent, average polar direction for alpha emission is found to vary very weakly within the range of deformation of known even-even nuclei [16,17]. As a matter of fact, from equations ( 9) and (10) the values of θ 0 have been calculated to give ∼53.4 • -54.7 • for prolate cases, and ∼54.8 • -56.0 • for the oblate-shaped nuclei.…”

14 Particle Decay Study of Oriented Nuclei

“…The latter are oriented relative to an axis in the laboratory frame. This implies that an angular momentum factor has to be introduced, similarly to the [19][20][21][44][45][46] be achieved in this way. This research was mainly conducted in the US at Oak Ridge and at Berkeley.…”

“…IID a lot of effort was put into the development of suitable detectors operating at low temperatures [19][20][21], Moreover, some very interesting measurements were carried out. In the actual experiments the anisotropic α-emission of 253 E, 249 Cf, 241 Am and 255 Fm grown into crystals of neodymium ethyl sulfate (NES) was studied down to temperatures of 11 mK by adiabatic demagnetization [21,44,45]. The experimental setup is shown in Fig.…”