Roper Scientific Inc.

Roper Scientific Inc. of Tucson, Ariz., designed and manufactured the CCD-based Photometrics Cascade camera for low-light live-cell microscopy. It enables microscopists to boost signal as much as 1000 times without the need for external image-intensifier hardware, making it a cost-effective alternative to traditional intensified CCD cameras for a wide range of applications.

The Cascade is engineered to optimize the performance and utility of a frame-transfer chip that increases photon-generated charge in an extended serial register. High-voltage clocking initiates and sustains a low-noise impact ionization process that multiplies the charge before it reaches the on-chip amplifier. The gain factor effectively reduces the CCD's read noise for a better signal-to-noise ratio.

The low read noise attained with on-chip multiplication gain means that images can be acquired at live frame rates, with individual frames added together in a host computer. The camera can detect a signal of less than 100 photons while operating at supravideo frame rates, which helps to decrease sample exposure to the bleaching effects and toxicity of illumination energy.

Applications for the camera include intracellular ion imaging, single-molecule fluorescence and biological fluid flow measurements.