Photomultiplier tube module


The H7422 series are photomultiplier tube modules with an internal high-voltage power supply circuit and a cooler installed to the metal package photomultiplier tube having a GaAsP/GaAs photocathode. Efficient cooling was achieved by placing the cooler near the photomultiplier tube to reduce thermal noise emitted from the photocathode and a high S/N ratio can be obtained even at extremely low light levels.The H7422-40 has high sensitivity in the 300 nm to 740 nm wavelengths. The H7422-50 is sensitive along a wide spectral range from 380 nm to 900 nm. The photomultiplier tube is maintained at a constant temperature by monitoring the output from a thermistor installed near the photomultiplier and then regulating the current to the thermoelectric cooler.

Block diagram

To prevent damage by excessive light, the H7422-40/-50 and the H7422P-40/-50 series has a protection circuit that automatically turns off high voltage if the output current exceeds the preset current limit (approximately 10 µA). This protection circuit works whenever the preset current limit is exceeded, even for a very short moment. For example, in applications such as laser scanning microscopes, the output current may momentarily exceed the preset current limit of the protection circuit. This will trigger the protection circuit and interrupt measurement. For such applications, if the average output current is lower than the PMT module maximum rating (2 µA), we offer the H7422A-40/-50 and H7422PA-40/-50 series that uses a protection circuit with the preset current limit changed to approximately 50 µA and so allows continuous operation without turning off high voltage even if a momentarily high output occurs.


Photocathode Area Shape Round
Photocathode Area Size Dia.5 mm
Wavelength (Short) 300 nm
Wavelength (Long) 740 nm
Wavelength (Peak) 520 nm
Dimension (W x H x D) 56.0 x 36.0 x 104.0 mm
Input Voltage +11.5 to +15.5 V
Max. Input Voltage 18 V
Max. Input Current 62 mA
Max. Output Signal Current 2 μA
Max. Control Voltage 0.9 V
Recommended Control Voltage Adjustment Range +0.5 to +0.8 V
[Cathode] Radiant Sensitivity Typ. 189 (at 520 nm) mA/W
[Anode] Radiant Sensitivity Typ. 3.8 x 105 (at 520 nm) A/W
[Anode] Dark Current (after 30min.) Typ. 0.4 nA
[Anode] Dark Current (after 30min.) Max. 1 nA
[Anode] P Type Dark Count Typ. 100 s-1
[Anode] P Type Dark Count Max. 300 s-1
[Time Response] Rise Time Typ. 1 ns
Ripple Noise (peak to peak) Max. 0.6 mV
Settling Time Max. 0.2 s
Operating Ambient Temperature +5 to +35 ℃
Storage Temperature -20 to +50 ℃
Weight 455 g

Dimensional outline (Unit: mm)

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