Gamma Spectrometry Forum

Hello
I'm looking for the voltage divider wiring diagram for a Hamamatsu R580.
With a single connector.
It will be used with a GS-USB-PRO, so using 1.2M resistors?

Thank you
Eric

Erik,

A good scheme for the GS-USB-PRO is a total of 12M impedance or more. You can use smaller resistors but it will start affecting the voltmeter display, it will read higher voltage than actually supplied.

Typically as per the specs 2, 1 ,1 , 1,...., this means you put 2 MOhm between Cathode and D1 and 1M between the rest.

We add some high voltage capacitors between D7 & D8, D8 & D9, D9 & D10, no cap between D10 and Anode. Alternatively if you have 3kV caps you can solder one leg to ground.

Use good quality metal film resistors.

Good luck..

Steven

Hello

Thank you very much Steven.
If I understood correctly...

Eric - Your schematic is correct, but you could add the following info...
C = .01uf / 200V (or similar).
An alternative capacitor setup (as Steven mentioned) would be to use a single .01uf HV capacitor (1500 to 3000 volts) between K and Dy10 (cathode and last dynode).

Thanks
one more little detail!

In the alternative capacitor configuration, do you need 1 or 2 (3) capacitors?

Which is the best?


I did not forget on my diagram a resistance between the anode and D10

As stated in my previous post; a single (only 1) high voltage capacitor (~1500 to 3000v) from Cathode to Last Dynode, can be substituted for the scheme of using capacitors across the last few dynodes.

Yes, I missed your omission of the resistor between Dy10 and Anode. One is certainly needed.

iRad wrote: ↑

16 Dec 2022, 01:45

As stated in my previous post; a single (only 1) high voltage capacitor (~1500 to 3000v) from Cathode to Last Dynode, can be substituted for the scheme of using capacitors across the last few dynodes.

I have another probe wired this way?... would it be better if I removed two capacitors or moved them?
(the red cable and the resistors have been modified)

That also works, but is just overkill for what we are doing... No need to remove them.

ok
Merci

Sesselmann wrote: ↑

14 Dec 2022, 13:15

capacitors between D7 & D8, D8 & D9, D9 & D10, no cap between D10 and Anode

Btw, do you know the reason why capacitors are set between dynodes and not connected to ground (or +HV, if it's available)?