Hello,
I need to build an amplifier for a photomultiplier tube. I have scoured the net for suitable circuits but am struggling since there seem to be so many solutions.
I want to make something that is low noise and I will be sampling the output at speeds up to 5 MegaSamples per second.
I am likely to require a gain of about 300.
Should I amplify in two stages. Perhaps two inverting amplifiers.
What sort of OP amp should I use? I have seen these which others have used for similar purposes
LT1012. http://www.linear.com/product/LT1012
Would an instrumentation amplifier be better.
In speaking to people, the frequency should be specified. Since I am sampling at 5 MS/s at the very most, I think that the most I would need to filter at is about 2 MHz. What would be the best way to add a filter to the circuit (active/passive) and how do I calculate the resistor/capacitor configuration?
The PMTs I want to use produce somewere between 2 uA and 100 uA current output maximum depending on the type. An example is H10770PA-40.
These are relatives of the following so are likely to have similar specifications
http://www.hamamatsu.com/resources/pdf/etd/m-h7422e.pdf
Can anyone point me in the right direction? I am thinking of two stages of inverting amplifier, say gain of x3 then x100 but I don't know how to design the filters, where to put them in the circuit, or what value range of resistors to use to give the right gain with lowest noise. I know how to calculate the gain for an inverting amp but not whether I should use low ohm values or high ohm values for best results.
I have a basic knowledge of electronics and can wield a soldering iron but not much experience in designing circuits, particularly ones for fairly high spec low noise applications.
Hope you can help,
Thanks,
Best wishes,
Nick H
I need to build an amplifier for a photomultiplier tube. I have scoured the net for suitable circuits but am struggling since there seem to be so many solutions.
I want to make something that is low noise and I will be sampling the output at speeds up to 5 MegaSamples per second.
I am likely to require a gain of about 300.
Should I amplify in two stages. Perhaps two inverting amplifiers.
What sort of OP amp should I use? I have seen these which others have used for similar purposes
LT1012. http://www.linear.com/product/LT1012
Would an instrumentation amplifier be better.
In speaking to people, the frequency should be specified. Since I am sampling at 5 MS/s at the very most, I think that the most I would need to filter at is about 2 MHz. What would be the best way to add a filter to the circuit (active/passive) and how do I calculate the resistor/capacitor configuration?
The PMTs I want to use produce somewere between 2 uA and 100 uA current output maximum depending on the type. An example is H10770PA-40.
These are relatives of the following so are likely to have similar specifications
http://www.hamamatsu.com/resources/pdf/etd/m-h7422e.pdf
Can anyone point me in the right direction? I am thinking of two stages of inverting amplifier, say gain of x3 then x100 but I don't know how to design the filters, where to put them in the circuit, or what value range of resistors to use to give the right gain with lowest noise. I know how to calculate the gain for an inverting amp but not whether I should use low ohm values or high ohm values for best results.
I have a basic knowledge of electronics and can wield a soldering iron but not much experience in designing circuits, particularly ones for fairly high spec low noise applications.
Hope you can help,
Thanks,
Best wishes,
Nick H