Photon counting head


The H8259 series is a photon counting head device containing a 28 mm (1-1/8") diameter side-on photomultiplier tube, high-speed photon counting circuit, and a high-voltage power supply circuit. The photomultiplier tube sensitive in the near IR region usually has a large dark count due to thermal noise but high S/N measurements can be obtained since a low-noise photomultiplier tube is selected. The high voltage supply for photomultiplier tube and the discrimination level are preset to optimum values, allowing photon counting measurement by just connecting a +5 V supply. An electronic gate circuit (shutter circuit) is also included to eliminate extraneous light such as excitation light from the measurement.


Photocathode Area Shape Square
Photocathode Area Size 4 mm x 20 mm
Wavelength (Short) 185 nm
Wavelength (Long) 850 nm
Wavelength (Peak) 430 nm
Dimension (W x H x D) 38.0 mm x 95.0 mm x 50.0 mm
Input Voltage +4.5 V to +5.5 V
Max. Input Voltage 6 V
Max. Input Current 80 mA
Count Senstitivity at 300 nm Typ. 2.7 x 105 s-1・pW-1
Count Senstitivity at 400 nm Typ. 3.3 x 105 s-1・pW-1
Count Senstitivity at 500 nm Typ. 3.2 x 105 s-1・pW-1
Count Senstitivity at 600 nm Typ. 2.3 x 105 s-1・pW-1
Count Senstitivity at 700 nm Typ. 6.8 x 104 s-1・pW-1
Count Senstitivity at 800 nm Typ. 1.6 x 104 s-1・pW-1
Count Linearity 2.5 x 106 s-1
Dark Count Typ. 80 s-1
Dark Count Max. 200 s-1
Pulse-pair Resolution 35 ns
Output Pulse Width 30 ns
Output Pulse Height Min. 2 V
Output Pulse Height Typ. 2.2 V
Recommended Load Resistance 50 Ω
Signal Output Logic Positive logic
Operating Ambient Temperature +5 ℃ to +40 ℃
Storage Temperature -20 ℃ to +50 ℃
Weight 220 g

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