Fission probabilities of Cu, Nb, Ag, Ho, Au and Bi nuclei excited by stopped antiprotons

Abstract

Abstract. The A dependence of nuclear fission induced by stopped antiprotons has been measured. An unambiguous identification of the binary fission decay mode was provided by a coordinate measurement of complementary fission fragments in coincidence using a large-acceptance fission detector based on low pressure multiwire proportional chambers. A deep fissility minimum was observed near A = 100, in agreement with the general behaviour predicted by the liquid-drop model. An unexpectedly low and high fission probability was found for the Ag and Cu nuclei, respectively.

Fission studies with 140 MeVαparticles

“…The minimum of the fission probability around Z 2 /A=20 predicted by calculations within the liquid drop model [5] and in a more refined model [29,30] is not seen here but a minimum in the vicinity of Z 2 /A=24. This is in agreement with proton induced fission at energies close by and in photo-fission [31,32].…”