THE MAGNETIC LEVITATION ELECTROMETER AND ITS USE IN THE SEARCH FOR FRACTIONALLY CHARGED PARTICLES.

Abstract The operation of the magnetic levitation electrometer both in the static and in the resonance version is described in detail. The sensitivity of the instrument in the resonance version allows measurements of charge to a precision often better than 1 20 e in grains of matter (graphite) having a mass of the order of 5×10−7g. On a total amount of 3.4 × 10−6g of pyrolitic graphite explored, corresponding to ≈2 × 1018 nucleons, no fractionally charged quark has been found.