Do cosmic rays account for superfluid 3He transition?

In theory, the transition between the two principal superfluid forms of liquid 3He ought not to be able to occur. So why is it routinely observed to take place? A possible answer to this intriguing question has recently been put forward by A.J. Leggett. Writing in Physical Review Letters 53, 1096; 1984, he suggests that the transition, although prohibited from occuring spontaneously, readily takes place because of the occasional high energy cosmic ray that passes through any experimental chamber on the Earth's surface