I wrote: About the beta-delayed gamma -- it's not clear that the 63Ni* gamma decay > is a beta-delayed gamma in this instance (see the decay in [1]). But as > you know beta-delayed gammas are a frequent occurrence. The half-life of > the beta decay in this case is 100 years, so if there is beta-delayed gamma > emission, the activity would be significant. >
The excited state after a beta- decay would be in the daughter (63Cu) not the parent (63Ni). I don't see any evidence for a 63Cu* excited state. You are probably right. Embarrassing rookie error on my part. Eric