A Geiger counter, also called a Geiger-Muller (GM) counter, is a type of particle detector that measures ionizing radiation. It detects the emission of nuclear radiation: alpha particles, beta particles, and gamma rays by the ionization produced in a low-pressure gas in a Geiger-Muller (GM) tube, which gives its name to the instrument.
A High Voltage generator (U1, U2, Q1, T1, and associated components) powers a GM tube. A pulse from the GM tube is interfaced through Q2 and U1 to pulse-generator U3, which drives a speaker.
Geiger Counter - [Link]
by JamecoElectronics @ instructables.com:
Build a DIY geiger counter that uses a PIN photodiode as a substitute for an expensive Geiger-Mueller tube. It detects alpha and beta radiation particles. The circuit is soldered onto a small protoboard and everything is placed in an aluminum enclosure. Copper tubing and a piece of aluminum foil is used to help filter out noise and RF interference.
Pocket Photodiode Geiger Counter - [Link]
By Ben Coxworth @ gizmag.com:
Ever since the Fukushima nuclear reactor disaster, there has understandably been an upsurge in the sale of consumer radiation-detecting devices. Most of these gadgets are variations on the Geiger counter, in that they alert the user to the presence and level of radiation, but not the type of radiation – which is very important to know. Researchers at Oregon State University are hoping to address that situation, with the MiniSpec. Currently in development, the handheld device will additionally tell its users what type of radionuclide is creating the radiation, and whether it poses a risk.
Small, portable and cheap radiation detector is being designed for the public - [Link]
Sean Bonner writes:
We wanted to do something special for the Kickstarter community, who helped us get Safecast moving in the first place, and thought that a limited edition version of the geiger counter we designed, at a discounted price, would be a cool way to do that.
So here you go: a Kickstarter exclusive Safecast geiger counter. Limited clear plastic casing (like these pics), numbered edition of however many people pre-order them here. The only way ever to get this clear version is from this Kickstarter campaign. Obviously, this edition is a real working geiger counter, 100% functionally identical to the forthcoming retail release version.
Safecast X Kickstarter Geiger Counter - [Link]
Sergei Bezrukov writes:
The radiometer is based on СБМ-20 Geiger counter tube which is manufactured in Russia and could be found on E-Bay. The counter is in a thin metal hull, so only beta and gamma rays can snick through it. It’s working voltage is in the range 350 – 450 V, the dead time does not exceed 190 μs, and the sensitivity is about 78 pulses per micro-roentgen. Therefore, maximum frequency of pulses provided by the counter is 106 / 190 = 5263 Hz. Respectively, the maximum radiation level one can register with it is 5263 / 78 = 67.47 μR/s, which is about 243 mR/h. The embedded firmware, however, can work up to 1 R/h.
Radiation dosimeter – Geiger counter – [Link]
The counter is sensitive enough to detect background radiation. In addition you can enhance the basic Geiger Counter by adding a Digital Meter Adapter, RS-232 Adapter with free Windows Radiation monitoring program or a Randam Number Generator. The windows 98/XP radiation program is free and available for downloading. [via]
Build Your Own Geiger Counter - [Link]