Fission of odd-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>A</mml:mi></mml:math>and doubly odd actinide nuclei induced by direct reactions

Abstract

Fission probability distributions have been measured using ($d,pf$), ($t,pf$), ($^{3}\mathrm{He},df$), ($^{3}\mathrm{He},\ensuremath{\alpha}f$), and ($t,\ensuremath{\alpha}f$) reactions to excite a variety of odd-$A$ and odd-odd actinide nuclei. Fission of the residual nuclei $^{229,231}\mathrm{Th}$, $^{231,232,233}\mathrm{Pa}$, $^{234,235,236,237,238,239}\mathrm{Np}$, $^{241}\mathrm{Pu}$, $^{240,241,243,245,247}\mathrm{Am}$, $^{249}\mathrm{Cm}$, and $^{249}\mathrm{Bk}$ was studied. These results and other data available from previous ($d,pf$), ($t,pf$), and ($n,f$) studies are analyzed with a statistical model to obtain estimates of the heights and curvatures of one or both peaks of the double humped fission barrier. Estimates of barrier parameters are obtained for the above nuclei and for $^{233}\mathrm{Th}$, $^{235,237,239}\mathrm{U}$, $^{239,243,245}\mathrm{Pu}$, $^{242,244}\mathrm{Am}$, $^{245,247}\mathrm{Cm}$, and $^{253}\mathrm{Cf}$. Systematic variations of the barrier parameters are discussed.NUCLEAR REACTIONS, FISSION Measured fission probabilities, ${E}^{*}\ensuremath{\le}7.5$ MeV for $^{229,231}\mathrm{Th}$, $^{231,232,233}\mathrm{Pa}$, $^{234,235,236,237,238,239}\mathrm{Np}$, $^{241}\mathrm{Pu}$, $^{240,241,243,245,247}\mathrm{Am}$, $^{249}\mathrm{Cm}$, and $^{249}\mathrm{Bk}$ using ($d,pf$), ($t,pf$), ($^{3}\mathrm{He},df$), ($^{3}\mathrm{He},\ensuremath{\alpha}f$), and ($t,\ensuremath{\alpha}f$) reactions. Deduced properties of the double peaked fission barrier for these nuclei and for $^{233}\mathrm{Th}$, $^{235,237,239}\mathrm{U}$, $^{239,243,245}\mathrm{Pu}$, $^{242,244}\mathrm{Am}$, $^{245,247}\mathrm{Cm}$, and $^{253}\mathrm{Cf}$.