Radiative Cooling of an Electrodynamically Contained Proton Gas

Abstract
On a gas of ∼104 protons, contained at ∼10−11 Torr in a parabolic rf trap of depth between 2.6 and 10.4 V, equilibrium temperatures kTi≃0.1 e and storage times T≃100 sec were measured ordinarily, both apparently determined by ``evaporation'' processes. When cooling the ions by coupling their disordered oscillatory heat motion to an LC circuit at room temperature, Ti dropped another factor of 3 to as low as 900°K and T increased to ∼3000 sec.