Radiation detectors : can these be used for prospecting

[Atul Asthana]

Here is a link to radiation detectors, you can make at home.
Possibly searching/prospecting for radioactive material?
http://www.techlib.com/science/ion.html
'Sensitive homemade ion chambers for detecting nuclear radiation are fairly easy to build but the circuitry is tricky and should only be attempted by "seasoned" experimenters - the currents are likely to be well below 1 pA unless there is a serious nuclear war in progress! (The simple version is "beginner friendly"!) Special electronics is needed at the front end, typically called an "electrometer" circuit, which produces an output voltage in proportion to the input current. The electrometer must have a very low bias or leakage current to avoid masking the desired signal and the intrinsic impedance of the amplifier must be extremely high. The input impedance of the electrometer may be fairly low, however, using feedback to convert the tiny current into a usable voltage.'