On Sat, Sep 20, 2014 at 7:40 AM, Jones Beene <[email protected]> wrote:
This elegant possibility of a gainful reaction in which stable nickel > converts to stable nickel, giving up energy, is why my prediction for the > Mizuno presentation in November is to suggest that they will see a relative > decrease in Ni58 and a relative increase in Ni60. > As an alternative prediction, if there is deuteron stripping rather than deuteron capture and then decay, one will see this: 58Ni + d → 59Ni + p 59Ni → 59Co + β+ (< 1 percent of the time) β+ + β- → 2ɣ Q (511 keV each) So there would be an excess of 59Co together with annihilation photons. The annihilation photons would be difficult to fully shield, although their rate is due to the half-life of the 59Ni decay and only indirectly tracks the rate of the reaction itself. Because the β+ decay rate is much smaller than any inferred reaction rate, the annihilation photons will only intermittently escape through the metal casing and make it into the detector, which has a relatively small aperture (compared to a full solid angle) and is less than 100 percent efficient (e.g., 26 percent efficient). With these things in mind, you wouldn't necessarily see annihilation photons above background. But the 59Co should increase significantly above its normal amount. The β+ decay occurs in only a very small number of cases. Most of the time (99 percent) the decay is via electron capture, a point I have missed up to now. So that will attenuate the expected number of annihilation photons in my models by two orders of magnitude. The decay, of course, is still to 59Co. Eric
