This is a teardown of a STRATEC Scintillation probe. I bought this one used. It seemed to be in a great shape with no visible damages on the outside.
The probe was made in the late 80s or early 90s. It was presumably used with a gamma spectroscopy unit.
There are three connectors at the baseplate. the left one is for the negative high voltage, the right one for the signal and the center one, of which only two pins are used is also for the signal. When using a negative high voltage, you need separate wires for HV and Signal whilst when using positive HV you can also use a splitter and have only one wire for both.
The scintillator crystal is a NaI(Tl) eg. Sodium Iodide doped with Thallium. It was made in Hungary which is very interesting because Hungary at that time was part of the eastern socialist part of the world while western germany, where the probe is made, belonged to the western world. The number of the scintillator crystal is 53, I also own number 64. I assume that they were not mass produced. At the bottom there is a hole to insert a sample to be analyzed.
Taking it apart it unveils a photomultiplier (pmt) with a mu metal shield wrapped around the pmt. The pmt itself is somehow bound to the scintillation crystal with a silicone compound similar to sealing silicone that hardens.
I managed to take the tube base apart to find out the pinout of the tube.
You can clearly see, that the manufacturer has left the focus electrode pin out. That saved me from a lot of work knowing that there is no need to deal with that.
The finished voltage divider looks like that. I used 2*R between K and D1. and 1*R for all following. There is a 4.7nF 1.5kV capacitor between D8 and D9 aswell as D9 and D10 (but not on the photo).
It follows my standard scematic:
