FLUCTUATION PROPERTIES AND CHARGE RESOLUTION OF THE SUPERCONDUCTING SET ELECTROMETER IN THE REGIME OF COOPER-PAIR TUNNELING

Single-charge tunneling through a voltage-biased SSS transistor with a capacitively coupled gate and an electromagnetic environment is consi dered. The dc Cooper-pair current in the blockade region of quasiparti cle tunneling is studied. Basing on a two-level approximation. which c an be used in the realistic case of low temperatures and small environ ment resistances, the mean de Cooper-pair current, the noise power spe ctrum, and the charge resolution are calculated as functions of the dr iving voltage and the external charge on the island.