Voltage divider for R580

[ChrisRadium2023]

Hello Madmax,
from what i understood on pmt electronics and experiments..

these caps are reservoirs caps : they are a reservoir of current in case the cps is too high in order to have a better linearity when the cps rise up. These are not decoupling capacitors (in wich case they would be connected to ground). So here the role of these caps is different.

If you remove them (you can try) the pmt will work but as soon as reach a certain of cps (counts per seconde) llimit your spectrum will shift or "shrink" as there wont be enough electrons to form all the pulses. The running of your pmt may even become less stable at high counts. Thats the reason it is said that the current in the voltage divider is calculated to be at least 20 to 100 times the mean current expected through the pmt.

For ex if in the data the mean current in 10uA then you can calculate the total resistance of the chain depending the maximum voltage allowed by the data. Especially if like me you're not using a specially designed high voltage pmt module that cannot deliver enough current.

Chris.