Intensified cameras

Special CCD cameras are used to acquire high-resolution images for scientific work. They are also called HCCD cameras. They belong to the two following classes cooled CCD cameras or intensified CCD cameras. Intensified cameras have been mostly used to follow spectroscopic fast events but they are now used in imaging to offer very high sensitivity. Cooled CCD cameras, however, offer better spatial resolution for luminescence work in the field of analysis and a broader combination of spectral ranges and sensitivity. 

In practice the trace obtained in this way is too faint to be seen when the electron beam scans the screen in a time of 1 ns. An image intensifier camera is needed to make it visible, and in a complete system this would be followed by a CCD camera to store the trace and transmit it to a computer. 

In recent years, multichannel detectors have become more and more popular, especially intensified linear diode arrays and CCD cameras. These devices offer a sensitivity similar to that of PMTs, while a complete spectrum can be recorded simultaneously. Apart from the substantial reduction in measurement time, another advantage is the fact that in the case of signal fluctuations (e.g., due to photodegradation, hole burning) all peaks in the spectrum are equally affected. For time-resolved detection a pulsed excitation source and a fast gateable intensified camera can be used. 

Systems Using Gated Image-Intensified Cameras... 

Oshiro M. Cooled CCD versus intensified cameras for low-light video—applications and relative advantages. Methods Cell Biol 1998 56 45-62. 

Figure 2.11 Water tank containing explosive column for aquarium test. The flood lights furnish the back lighting for the image intensifier camera.

Figure 2.23 The aquarium test for X0233. Two photographic exposures taken with the image intensifier camera. The shock wave in the water and the interface between the...

The zoom optics between the image intensifier and the video camera gives the freedom to magnify details of the image for more detailed inspection. 

Whereas scintillation screens can be used to directly view x-rays passing through the body, the dose to a patient is too high. Instead, scintillation screens are combined with video cameras or electronic intensifier tubes and video cameras. This detection scheme is used in digital radiography where digital x-ray images are recorded, and fluoroscopy where temporal processes are to be followed. 

FLIM systems can be purchased as an add-on for a standard fluorescence microscope. Such a system will consist of a CCD camera coupled to a modulatable image intensifier, an LED light source, and driver electronics. This system will modulate the LED and image intensifier while shifting the phase between them as it takes a series of images (Fig. 2.1). 

A more common approach to time domain wide field FLIM is based on a time-gated image intensifier MCP in combination with a CCD camera (see Fig. 3.8). After every excitation pulse the gated... 

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