HAMAMATSU IMAGE INTENSIFIER PDF

Status, Standard. Feature, Second Generation, High Resolution. Spectral Response (Short), nm. Spectral Response (Long), nm. Spectral Response. Image intensifiers were developed for military use to enhance our night vision. They have an input photocathode followed by a micro-channel plate electron. mamatsu Cx, C and C series image intensifier units consist .. Information furnished by HAMAMATSU is believed to be reliable. However, no.

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By incorporating on-chip multiplication gain, the electron multiplying CCD achieves, in an all solid-state sensor, the single-photon detection sensitivity typical of intensified or electron-bombarded CCDs at much lower cost and without compromising the quantum efficiency and resolution characteristics of the conventional CCD structure.

Image intensifiers were developed for military use to enhance inage night vision and are often referred to as wafer tubes or proximity-focused intensifiers.

Image intensifier unit C | Hamamatsu Photonics

They have a flat photocathode separated by a small gap on the input side of a micro-channel plate MCP electron multiplier and a phosphorescent output screen on the reverse side of the MCP. Substantial voltages are present across the small gaps between the photocathode, the phosphorescent output screen, and the MCP, which require careful construction of the devices to ensure they are free from contamination and can maintain high internal vacuums.

Proximity-focused intensifiers are free from geometrical distortion or shading because the photoelectrons follow short, direct paths between the cathode, output screen, and the MCP rather than being focused by electrodes.

Input and output windows are typically around 18 millimeters in diameter and consist of either a multialkali or bialkali photocathode Gen II intensifiers or a gallium arsenide photocathode Gen III omage Gen IV devices and a P20 output phosphor. The overall photon gain of these devices averages about 10, which is calculated according to the equation: When the voltage drop between the MCP and the output phosphor decreases below volts, the phosphor becomes unresponsive.

C9016-2x Series High-speed Gated Image Intensifier Unit

The photocathode in the latest generation of these devices, while similar to that in photomultiplier tubes, has a higher quantum efficiency up to 50 percent in the blue-green end of the spectrum.

The gain of the micro-channel plate is adjustable over a wide range with a typical maximum of about 80, a detected photon at the input leads to a pulse of 80, photons from the phosphor screen.

The phosphor matches the spectral sensitivity of the eye and is often not ideal for a CCD. Resolution of an intensified CCD depends on both the intensifier and the CCD, but is usually limited by the intensifier microchannel plate geometry to about 75 percent of that of the CCD alone. The latest generation of image intensifiers denoted blue-plus Gen III or sometimes Gen IV; Figure 2 employ smaller microchannels 6 micron diameter and better packing geometry than in previous models with a resultant substantial increase in resolution and elimination of the chicken-wire fixed-pattern noise that plagued earlier devices.

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The broad spectral sensitivity and high quantum efficiency Figure 2 of the “high blue” GaAs and gallium arsenide phosphide GaAsP photocathodes are ideally suited to applications in fluorescence or low-light-level microscopy.

Image intensifier VU | Hamamatsu Photonics

Image intensifiers have a reduced intrascene dynamic range compared to a slow-scan CCD camera and it is hamamatwu to obtain more than a fold intensity range 8 bits from an intensified CCD camera. Intensifier gain may be rapidly and reproducibly changed to accommodate variations in scene brightness, thereby increasing the interscene dynamic range.

Indeed, since image intensifiers can be rapidly gated turned off or on in a few nanosecondsrelatively bright objects can be visualized by a reduction in the “on” time. A gated, variable gain intensified CCD camera is commercially available with a 12 order of magnitude dynamic range.

Gated, intensified CCD cameras are required for most time-resolved fluorescence microscopy applications because the detector must be turned on and off in nanoseconds or its gain rapidly modulated in synchrony with the light source. Thermal noise from the photocathode as well as electron multiplication noise from the microchannel plate reduce the signal-to-noise ratio in an intensified CCD camera to below that of a slow-scan CCD.

The contribution of these components to the noise created by the statistical nature of the photon flux depends on the gain hamamxtsu the device and the temperature of the photocathode.

Generally, a reduction of the gain of the intensification stage is employed to limit the noise although intensified CCD cameras are available with a cooled photocathode. Intensified CCD cameras have a very fast response limited by the time constant of the output phosphor and often the CCD camera read out is the slowest step in image acquisition. Miage of the low light fluxes emanating from the fluorochromes bound to or within living iage, intensified CCD cameras are frequently employed to study dynamic events and for ratio imaging of ion-sensitive fluorochromes.

The simultaneous or near-simultaneous acquisition of two images at different excitation or emission wavelengths is required for ratio imaging and intensified CCD cameras have the requisite speed and sensitivity. Two of the most popular approaches for relaying the output of an image intensifier to a video-rate camera vidicon or CCD are using an optical relay lens coupling or a fiber-optic coupling.

Relay lenses are designed to capture light from the intensifier output window with minimal geometrical distortion or spherical aberration and project as much of the image as possible onto the video pickup device. The efficiency of a relay lens is given by the equation: When the input window of the video sensor CCD array size is smaller than the intensifier output window, the relay lens is required to demagnify the image to match the format of the sensor.

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Coupling efficiency increases proportionally with demagnification according to hwmamatsu efficiency equation given above. If the intensifier has sufficient gain and output luminance, the losses in the relay lenses may not adversely affect overall performance. Optical relay lenses work well with Gen II inverter tubes and some Gen III or Gen IV tubes coupled to Newvicon tube or CCD detectors because the high gain and high screen luminance of these intensifiers help to offset the inefficiency of the relay lenses.

The optimum method for coupling Proximity-focused image intensifiers to CCD sensors is through a fiber-optic taper Figure 1. This approach achieves a coupling efficiency between 40 and hamzmatsu percent with matching formats, but requires a high degree of skill in bonding the fiber-optic taper to both devices. Maximum efficiency and minimal fixed-pattern noise are achieved when the CCD front window is removed and the fiber-optic taper is machined to fit directly onto the diode array surface.

High resolution, artifact-free images require precision quality tapers having a small fiber diameter between 2 and 3 microns with very few missing or broken fibers hamamarsu low fixed-pattern noise. Bonding fiber-optic tapers to the CCD surface is relatively permanent, and CCD failure can lead to infensifier of an expensive image intensifier and fiber-optic taper.

Image intensifiers (IIs)

To alleviate this problem, improvements in nonpermanent, optically matched, silicon bonding materials make it possible to disassemble fiber-optic coupled systems without destruction. Tutorials Articles Contact Home. Electron Multiplying Charge-Coupled Devices EMCCDs By incorporating on-chip multiplication gain, the electron multiplying CCD achieves, in an all solid-state sensor, the single-photon detection sensitivity typical of intensified or electron-bombarded CCDs at much lower cost and without compromising the quantum efficiency and resolution characteristics of the conventional CCD structure.

Concepts in Digital Imaging Technology Proximity-Focused Image Intensifiers Image intensifiers were developed for military use to enhance our night vision and are often referred to as wafer tubes or proximity-focused intensifiers. Contributing Authors Kenneth R. Spring – Scientific Consultant, Lusby, Maryland,