Prototypical search for radioactive superheavy elements in gases

An electrostatic-precipitation device and its deployment in searches for decay products involving possible superheavy elements in gases is described. The continuous collection and detection of ions formed in a 38-liter volume of gas near atmospheric pressure were observed over month-long periods for the cases of helium, argon, and xenon via α-particle spectroscopy, which allowed limits to be placed on the possible concentration of superheavy elements in xenon that ultimately decay to members of the four traditional heavy α-particle emitters having atomic masses in the range 211≤A≤225. For assumed decay via fission, the general method is comparable in sensitivity to neutron-multiplicity methods, but it also possesses energy and lifetime identification characteristics as well as an accumulative nature as regards the decay products. Improvements that would extend the sensitivity to the 10-15 gram per gram level are described. (orig.)