Search for heavy-ion emission in ²⁴⁹Cf decay

Using phosphate glass detectors PKS-50, we have searched for possible emission of heavy clusters in the decay of ²⁴⁹Cf with the aim of confirming the result obtained from a recent γ ray spectrometry experiment. After a 20-day exposure to a 7.4 MBq activity ²⁴⁹Cf source of 37.5 cm² PKS-50 glasses covered with polymide foils to stop fission fragments, no ions with 17<~Z<~21 were detected. We could deduce an upper limit of the branching ratio (90% C.L.) b<~1.5×10^-12 and a partial half-life T_1/2>~7.4×10²¹ s. According to calculations performed on the basis of the preformed cluster model there seems to be very little chance that such an exotic decay might be detected, at least in the next few years.