The weak positron transition in the decay of 30P

The weak positron branch in the decay of 30P has been detected by using both gas flow and pneumatic transfer techniques in conjunction with a Ge(Li) detector. The log ft value for the transition to the first excited state of 30Si has been found to be (5.66+or-0.04), at variance with the previous experimental value and considerably different from the value calculated by Engelbertink and Brussaard. It has been shown that an increase in the d3/2 mixing in the 30P and 30Si nuclear states is required to explain this result.