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9 - PCB electrode design

A project log for Open Radiation Detector

Quickly identify radioactive materials with a pocket-sized ion chamber. Built from standard parts for easy manufacture and low cost.

carlos-garcia-sauraCarlos Garcia Saura 10/14/2017 at 10:010 Comments

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).


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