Make a very Sensitive geiger counter with a cheap muller tube from ebay and a disposable camera circuit !
there is an optional part of the circuit you don't need but is just a few more parts a logic level N-fet and a10k resistor are needed for the meter hookup . .the detector built without those two parts will have audio Clicks like a good detector when radioactivity is detected including background normal in the air particles . .Looking forward to your Builds !!
http://www.youtube.com/watch?v=G9Ljmo875kU (http://www.youtube.com/watch?v=G9Ljmo875kU)
thanks to Kirk @ mad Scientist Hut
http://madscientisthut.com/wordpress/category/geiger-counter/ (http://madscientisthut.com/wordpress/category/geiger-counter/)
http://www.ebay.com/itm/SI-39G-39-RUSSIAN-MADE-GEIGER-MUELLER-TUBE-DETECT-BETA-AND-GAMMA-RAYS-/280927906167?pt=Vintage_Electronics_R2&;;;hash=item41689ba977 (http://www.ebay.com/itm/SI-39G-39-RUSSIAN-MADE-GEIGER-MUELLER-TUBE-DETECT-BETA-AND-GAMMA-RAYS-/280927906167?pt=Vintage_Electronics_R2&;;;hash=item41689ba977)
http://www.ebay.com/itm/Military-Russian-Soviet-GEIGER-TUBE-COUNTER-SI-3BG-SI-3BG-SI3BG-3-NEW-/251148641400?pt=BI_Security_Fire_Protection&;;hash=item3a79a02478 (http://www.ebay.com/itm/Military-Russian-Soviet-GEIGER-TUBE-COUNTER-SI-3BG-SI-3BG-SI3BG-3-NEW-/251148641400?pt=BI_Security_Fire_Protection&hash=item3a79a02478)
The tubes are on ebay for about 10 bucks more or less but the plans call for a russian SBM20 geiger tube which is a bit more ..according to his plans The Russian surplus SBM20 runs fine at 280-500V , so I chose to set my output to ~340VDC because at this level it draws less current from the batteries.
the 10 dollar geiger counter tubes are rated Working Voltage in pulse mode = 380...460 V and Working Voltage in current mode = 382...398 V so they should work fine with this circuit as the only difference is less voltage to run them !
all the parts for this are less than 30 dollars including the tube and the cheap 3 dollar multimeter .
i can show you how the flash unit can also be a fuji instead of the one shown . Very simple modifications .
this probably is not for the unexperienced person .but if you can make a Darlington circuit then this is not that hard and you can use radioshack pcb project boards to solder your components . get a big enuff enclosure and you can put your meter ,speaker and make a tube enclosure out of a piece of pvc or copper pipe and some hv wire or satellite coax and you got a nice geiger counter .. Or you can buy a ready made detector for around 160 up . Stay away from the old Victoreen Yellow CD-v717 . It is not a Geiger counter even though it looks like one.
this is info available on the internet and brought to your attention to build one now because radiations is a real problem everywhere from the Japan disaster .
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If you just want to detect Ion radiation http://www.youtube.com/watch?NR=1&feature=endscreen&v=DtQ746MPrNs (http://www.youtube.com/watch?NR=1&feature=endscreen&v=DtQ746MPrNs)
http://www.youtube.com/watch?feature=endscreen&NR=1&v=cfVBW622Vbs
a 4 dollar Nuclear rad detector . Not very strong but if you have a good source like an americium dot or a thorium welding rod or an older camping lantern mantel stuck in it you can see it on your meter .
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