Happy holidays,
I am trying to design a UV light measurement circuit using a PMT (photon multiplier tube). These PMTs require a very high negative bias voltage (I'm using -500V) and include a number of dynodes that are used to convert received photons into a large, proportional number of electrons, via multiplication.
The dynodes are all connected via a multi-stage resistor divider (picture ten 330K resistors in series, from -500V to ground). To configure the circuit gain, I would like to enable and disable the divider elements applied to some of the dynodes.
I'm looking for a circuit that lets me remotely enable and disable the resistors feeding each dynode. The circuit needs to handle at least -500V (assume 10 dynodes in my PMT), and have a mechanism to switch between either of two resistor values.
I'm perplexed. Any suggestions for paths to pursue?
Thanks,
Gary
I am trying to design a UV light measurement circuit using a PMT (photon multiplier tube). These PMTs require a very high negative bias voltage (I'm using -500V) and include a number of dynodes that are used to convert received photons into a large, proportional number of electrons, via multiplication.
The dynodes are all connected via a multi-stage resistor divider (picture ten 330K resistors in series, from -500V to ground). To configure the circuit gain, I would like to enable and disable the divider elements applied to some of the dynodes.
I'm looking for a circuit that lets me remotely enable and disable the resistors feeding each dynode. The circuit needs to handle at least -500V (assume 10 dynodes in my PMT), and have a mechanism to switch between either of two resistor values.
I'm perplexed. Any suggestions for paths to pursue?
Thanks,
Gary