Good point. Jed knows the details of the mass spec Mizuno had available, which was damaged in the earthquake. IIRC it was being repaired when the paper was written and its present status has not been reported. Perhaps he will comment on this.
Surely Mizuno was looking for helium before his lab was destroyed - so it is expected that he knows how to resolve the small mass difference. It would certainly be most informative to have information about helium as a first priority… From: russ.geo...@gmail.com If one is working with a quadrapole mass spec, and especially a small one like an RGA it will be impossible to devolve the peaks of 4He and D2. Only by being certain that little D2 is present by trapping it in a cold or getter trap on the way to the mass spec can one ever be certain that the sample is 4He instead of D2. The practice is clearly informative as one learns the operation of the RGA with and without the cold trap.
