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We demonstrate that individual electron-hole pairs are resolved in a 1 cm² by 4mm thick silicon crystal (0.93 g) operated at ~35 mK. One side of the detector is patterned with two quasiparticletrap- assisted electro-thermal-feedback transition edge sensor arrays held near ground potential. The other side contains a bias grid with 20% coverage. Bias potentials up to ±160V were used in the work reported here. A fiber optic provides 650 nm (1.9 eV) photons that each produce an electronhole (e-h+) pair in the crystal near the grid. The energy of the drifting charges is measured with a phonon sensor noise σ ~0.09 e- h+ pair. The observed charge quantization is nearly identical for h+s or e-s transported across the crystal. [ABSTRACT FROM AUTHOR]

To increase levels of sound attenuation, it is often necessary to utilize active acoustic control methods. A complete active acoustic control system typically consists of sensing devices, an electronic control circuit, and an actuating device. Each component is designed to cause destructive interference of the impressed acoustic pressure field. A piezocomposite actuator is presented for active underwater attenuation control of an impressed acoustic field. The actuator is composed of bilaminate plates for absorption of both the reflection and the transmission of normally incident acoustic waves independent of the backing impedance. An electromechanical model of the bilaminate piezocomposite design with an analytical discussion is presented. An illustrated numerical example and discussion of system implications are included. [ABSTRACT FROM AUTHOR]