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Home > Articles >Build Your Own Geiger Counter, Page 7
Radioactive Sources
Uranium ore is available from a number of sources including eBay and our online store.
A
more reliable source is to purchase a radioactive source. Small amounts
of radioactive materials are available for sale encased in 1 inch
diameter by ¼" thick plastic disks. The disks are available to the
general public license exempt. This material outputs radiation in the
micro-curie range and has been deemed by the Federal government as
safe.
The cesium-137 is a good gamma ray source. The cesium-137 has a half-life of 30 years.
Check Out
Turn
on the Geiger counter. If you have a radiation source bring it very
close to the GM tube. The radiation will cause the Geiger counter to
start clicking. The LED will pulse with each click. Each click
represents the detection of one of the radioactive rays; alpha, beta or
gamma.
Background Radiation
Background
radiation, from natural sources on earth and cosmic rays will cause the
Geiger counter to click. In my corner of the world I have a background
radiation that triggers the counter 12-20 times a minute.
Parts List
The complete parts list including case is available as the GCK-02 kit for $149.95
GM Geiger Mueller Tube
T1 HV mini step up transformer
C1 .0047 uF capacitor
C2 .01 uF capacitor
C3,C10 100 uF capacitor
C4,C5 .01uF 1KV capacitors
C6 1.0 uF 12V capacitor
C7 .047 uF capacitor
C8 .01 uF capacitor (16v)
D1 1N914 diode (or equiv.)
D2,D3,D9 1N4007 1KV diodes
D4 1N5271 100 volt zener diode
D5,D6 1N5281 200 volt zener diode
D7 Red LED Chrome case with mounting hardware
SPK Speaker
R1 4.3K ohm 1/4 watt resistor
R2 15K ohm 1/4 watt resistor
R3 5.6K ohm 1/4 watt resistor
R4 10 mega ohm 1/4 watt resistor
R5 470 K ohm 1/4 watt resistor
R6 100 K ohm 1/4 watt resistor
R7 47 K ohms 1/4 watt resistor
SW1 Panel Mounted On-Off switch
SW2 Panel Mounted On-Off switch
U1 4049 Hex Inverting Buffer
U2 555 Timer
U3 7805 Voltage Regulator
Q1 IRF830 MOSFET Transistor
Q2 2N3904 NPN Transistor
2 9-Volt battery terminals PC mount (PCB only)
1 470 ohm 1/4 watt resistor (for optional headphones)
3 3.5MM jacks (For additional options; head phones; digital out, external power supply)
1 Nylon screw and nut (2-56) for mounting PCB to enclosure)
Misc. Case, LED holder, LED cable, On-OFF switch, 9V battery cap, Geiger Counter Case
GCK-02 Complete Geiger Counter Kit (all components) $169.95
Components that are sold separately (click for more info or to purchase):
GM tube $64.95
Mini Step-up transformer $15.00
Geiger Counter PCB $10.00
Radioactive Sources (click for more info or to purchase):
Uranium Ore $24.95
CS-137 Source $94.00 * Drop shipped from different location
Part 2 Building Your Own Geiger Counter -- Geiger
Counter Enhancements & Options
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