Here are some detailed pictures on the construction of the most important part of the detector: the inner amplifying electrode.

The central electrode is a surface-mount stud that captures the tiny ionization currents within the chamber. It is tightly coupled with the Darlington transistor that amplifies the signal (see the previous log entry for the schematic), this is done in order to reduce electrical noise.

Here is how the electrode assembly looks with the shielding can removed:
On the bottom can be seen the instrumentation amplifier that conditions and further amplifies the signal while compensating for the temperature effects (see entries 5 and 8).