Design and Fabrication of Large CCDs for the Keck Observatory DEIMOS Spectrograph

Abstract

The Keck II Deep Imaging Multi-Object Spectrograph (DEIMOS) is a general purpose, faint object, multi-slit, double-beam spectrograph which offers wide spectral coverage, high spectral resolution, high throughput, and long slit length on the sky. This powerful instrument will be the principal optical spectrograph on the Keck II telescope. DEIMOS is optimized for faint-object spectroscopy of individual point sources, low-surface-brightness extended objects, or widely distributed samples of faint objects on the sky. To obtain high resolution (∼ 1 å) and wide spectral coverage (up to 5000 å) the spectrograph uses wide angle cameras and large CCD detectors with many pixels.This paper describes some of the work being carried out to obtain the CCD detectors required for the DEIMOS spectrograph. In addition, results are presented on the fabrication and characterization of a 4k × 2k three-side buttable CCD produced by Orbit Semiconductor, a silicon foundry in San Jose, California. This CCD was fabricated to test the ability of Orbit to produce high quality scientific CCDs with the characteristics required for detectors to be used in DEIMOS and other optical instruments of the Keck Observatory.