PMT Controller and Power Supply

The Janelia PMT Controller is an updated design for use in high-performance microscopy systems. It was designed and built to meet the needs of the new large field of view 2 photon random access mesoscope, also available via license or purchase. You can find the complementary PMT Amplifier here.

Hardware Overview

The PMT Controller provides two channels of control for GaAsP Photo Multiplier Tubes. The low-noise design uses static logic, linear power supplies, and AC line filters. The control voltages are independently adjustable over their entire range via multi-turn controls, with the voltages displayed on the built-in meters. Each PMT can be switched on and off independently. A trip circuit is built-in to detect high PMT currents. Users can independently set trip levels and duration for each channel. A trip condition turns off both PMTs and can be reset via a front panel control. External control of high voltage and trip reset are also provided.

Hardware Development

Engineers took care to eliminate switching noise in the controller, so only the panel meters use switching electronics. 
The trip detects circuits have some high-frequency noise filters (~30kHz), followed by a level comparator with an adjustable threshold, followed by an adjustable trip delay circuit. A trip detection occurs when the input signal reaches a particular threshold and lasts a certain duration. The two trip signals are OR’ed together to create a single trip event if either input satisfies the trip requirements. This, in turn, sets a latch to turn off the high voltage control and a trip indicator LED. The trip condition can be reset using the Trip Reset switch. Each channel can be turned on and off independently, and there is a common high voltage control.

Opportunity:

The designs and documentation are available under a non-commercial, open-source license at Flintbox (link at right). 

Commercial licenses are also available. 

Janelia Tech ID:

Please reference 2017-017 in inquiries.