Radiation Shielding - Detecting Different Radiation
I have been asked on a few occasions about proportional geiger counters; geiger counters that can differentiate between Gamma, Beta and Alpha radiation. While these GM tubes are available, they are much more expensive and require a variable HV power supply. The tube’s voltage is varied to different preset voltages to detect different radiation.
A simpler method is to provide radiation shielding to your GM tube. To block alpha radiation cover the front mica window of the GM tube with a few sheets of paper. This will effectively block the alpha radiation and allow just beta and gamma radiation through to the tube to be detected.
To block alpha and beta radiation; cover the tube with 1/8” thick aluminum. This will effectively block the alpha and beta radiation and allow just the gamma radiation through to the tube to be detected.
To effective block gamma radiation, depending upon the energy of the radiation, you may need several inches of lead.
Granted this simple shielding doesn’t provide the versatility and usefulness of a proportional counter, in some cases you will find it helpful.
Going Further - Data Logger
The PC interface circuit can be a springboard to more geiger counter projects. For instances the addition of an LCD display to make a digital geiger counter or perhaps a graphing LCD module. Perhaps one could add a EEPROM memory and create a portable data logger. If you would like to see more enhancements for this geiger counter write me and let me know..