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ITTIL Deflectable Photomultipliers
Tube photomultiplicateur



These low-noise photomultipler tubes with focusing find applications in the following domains: stellar observations, star tracking, laser detection, vibration analysis, scintillation counting.


Deflectable Type PMT


These photomultipliers make use of magnetic focusing of the photoelectrons from the photocathode to produce an image in the plane of an aperture between the cathode and the first dynode of the multiplier structure:


Schematic cross section of a focusing, low-noise photomultiplier tube


Therefore, the effective photocathode area from which photoelectrons can pass through the aperture and enter the multiplier structure is much smaller than the actual size of the photocathode. In practice, the effective instantaneous photocathode diameter (IPD) ranges between 0.125 and 12.5 mm, depending on the size of the aperture.

As a result of this type of design, a large fraction of the thermionic emission current from the photocathode and corresponding noise current is eliminated. Thus, extremely low noise levels can be achieved when pulse operation is used to count pulses due to single photoelectrons from the cathode, with pulse height discrimination to eliminate sources of noise other than thermionic emission from the photocathode, e.g., thermionic emission from the dynodes, fluctuation in ohmic leakage, etc. Equivalent noise inputs as low as 10-17-10-18 watt have been obtained using such phototubes. The use of external magnetic deflecting coils between the cathode and aperture plane allows the effective cathode area to be moved at will over the actual cathode, so that such “deflectable” photomultiplier tubes can be used for star tracking and similar purposes.


ITT Deflection Coil

Example of a deflection coil

ITT Electro-Optic Devices - Photo-Multipliers
Cooling Characteristics of ITTIL Multiplier Phototubes
U.S. Patent 2,795,547

On this website:
ITTIL FW118 16-Stage Deflectable Photomultiplier
ITTIL Deflectable Photomultiplier FW-129 G
ITTIL FW-130 Deflectable Photomultiplier with Products for Research PR-1000 Housing
ITTIL FW-130 Deflectable Photomultiplier with ZIMMER OHG Housing
ITTIL FW-142 Ruggedized Photomultiplier for Single-Electron Counting


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