Photometrics Cascade Digital Camera
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.
- A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture and a shutter of variable speed to precisely control the exposure. In an electronic imaging system, the camera does not use chemical means to store the image, but takes advantage of the sensitivity of various detectors to different bands of the electromagnetic spectrum. These sensors are transducers...
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