<title>New developments in CCD imaging devices for low-level confocal light imaging</title>

Abstract

Charge coupled devices (CCD) have several advantages over tube camera imaging devices. These advantages include: geometric stability, high dynamic range (12, 14, or 16 bits) and photometric linearity. In order to achieve low-readout noise the readout is usually limited to 50 kpixels per second. The readout time is several times longer than video rates; the slow readout at less than video rates is the major disadvantage. A new CCD imager has been coupled to a Nipkow disk, confocal light microscope and its performance is evaluated using both reflected light and low-light-level fluorescence imaging. The CCD imager is a TK515, silicon CCD which is sensitiveequalsve from the UV to the near-IR. The sensor is a full frame area imager, with CCDs fabricated using a buried channel, three-level polysilicon gate process with very high charge-transfer efficiency (>0.9999) and low dark current. Low noise on-chip amplifiers provide and interface to external preamplifiers with readout noise typically <10 electrons at -90 degree(s) C, and 50 kpixels/second data rate. The chip is a thinned, back-illuminated device with anti-reflection coatings. The quantum efficiency is >80% at 400 nm and >90% at 600 nm. To determine its performance the Tektronix CCD was mounted in a Photometrics liquid cooled camera, attached to a Technical Instruments K2Bio confocal microscope.