It sounds to me like GP is hinting that the rate of particle emission for a given mass of uranium (maybe just the more fissile U-235?) is deliberately misreport

It sounds to me like GP is hinting that the rate of particle emission for a given mass of uranium (maybe just the more fissile U-235?) is deliberately misreported in the literature. The way people originally determined that value experimentally was to count the light flashes produced over a period of time by a source of ionizing radiation placed at one end of a vacuum tube. I'm not a physicist, so hopefully someone can correct me if I'm barking up the wrong tree here.