CMB and Astrophysics Theory
Charge-coupled devices (CCD's) are the imagers of choice in astronomy. The conventional thinned rear-illuminated n-channel CCD's have limitations which are overcome by the innovative LBNL "shocking red" design. This p-channel device is made on very high resistivity silicon, and in operation the entire 200-600 um substrate is totally depleted. Because it is thick, it is uniquely sensitive to near-infrared light. Since it has no field-free region, it has the best available spatial resolution. It is up to an order of magnitude more radiation resistant than normal n-channel devices. This CCD is proposed as the SNAP optical imager, but large-format devices will also be deployed on ground-based telescopes (such as the Keck) as soon as possible. The SNAP poster image shown above was obtained with such an imager at Kitt Peak, and another has permitted the UCB et al. planet search group at Lick Observatory to significantly reduce their radial velocity errors, permitting detection of lower-mass exoplanets.