Calculated fission-fragment mass yields and average total kinetic energies of heavy and superheavy nuclei
M. Albertsson, B. G. Carlsson, T. Døssing, P. Möller, J. Randrup, Sven Åberg
Abstract
Abstract Fission-fragment mass and total-kinetic-energy (TKE) distributions following fission of even-even nuclides in the region $$74 \le Z \le 126$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>74</mml:mn><mml:mo>≤</mml:mo><mml:mi>Z</mml:mi><mml:mo>≤</mml:mo><mml:mn>126</mml:mn></mml:mrow></mml:math> and $$92 \le N \le 230$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>92</mml:mn><mml:mo>≤</mml:mo><mml:mi>N</mml:mi><mml:mo>≤</mml:mo><mml:mn>230</mml:mn></mml:mrow></mml:math> , comprising 896 nuclides have been calculated using the Brownian shape-motion method. The emphasis is the region of superheavy nuclei. To show compatibility with earlier results the calculations are extended to include earlier studied regions. An island of asymmetric fission is obtained in the superheavy region, $$106\le Z\le 114$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>106</mml:mn><mml:mo>≤</mml:mo><mml:mi>Z</mml:mi><mml:mo>≤</mml:mo><mml:mn>114</mml:mn></mml:mrow></mml:math> and $$162\le N\le 176$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>162</mml:mn><mml:mo>≤</mml:mo><mml:mi>N</mml:mi><mml:mo>≤</mml:mo><mml:mn>176</mml:mn></mml:mrow></mml:math> , where the heavy fragment is found to be close to $$^{208}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>208</mml:mn></mml:msup></mml:math> Pb and the light fragment adjusts accordingly. Most experimentally observed $$\alpha $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>α</mml:mi></mml:math> -decay chains of superheavy nuclei with $$Z > 113 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Z</mml:mi><mml:mo>></mml:mo><mml:mn>113</mml:mn></mml:mrow></mml:math> terminate by spontaneous fission in our predicted region of asymmetric fission. In these cases, the pronounced large asymmetry is accompanied by a low TKE value compatible with measurements.