The 70705 Photomultiplier Power Supply provides the highly regulated voltage needed for precision measurements with Oriel Photomultiplier Tubes. Since the signal current varies as the 5th to 10th power of the supply voltage (depending on the PMT), stability of the voltage supply is vital. It is used to supply negative voltages to -2000 V, and has a positive ground. This facilitates connection of the output (anode) to our current measuring equipment.
Dual Outputs for Ratio Measurements
The 70705 Power Supply has an LED digital display and two high voltage BNC outputs for photomultiplier tubes. Since both outputs are on the same power supply, this ensures that two similar PMTs can be operated with a minimum of independent drift. This can be critical when one PMT is monitoring a reference light beam, for instance, while the other is measuring the sample signal.
Remote Controls
The 70705 provides the ability to control output voltages, both the value (0 to 9 V analog input) and ON/OFF. The ON/OFF feature can be used for an interlock function, for operator safety, and/or to protect the PMT from excess light such as may occur when changing samples.
Complete PMT Systems
We offer complete PMT systems, or you can assemble your own system, here we suggest a few additional solutions, if you're putting together your own PMT system. PMTs function as current sources. Therefore, you need either a transimpedance amplifier or a resistor to convert the output current to voltage for the reading electronics to measure signal strength.
For DC to 100 kHz operation, we suggest the Low Noise Current to Voltage Preamplifier providing gains from 104 to 109 V/A and selectable filter functions. For pulsed operation use the 70721 or 70723 with 50 Ohm input impedance to boost a 1 µA signal to a few millivolts while minimizing reflections. The 70703 or 70709 Laboratory Power Supply provides the ±15 V, and +5 V outputs to satisfy the requirements of our amplifiers.
