geiger counters

[glennster]

so i found this on ebay and for 70 dollars just had to get one. i remember all the old b sci fi movies in the 50 s where the sherrif always carried one in the back seat of the squad car. just in case of a mutant radioactive gila monster, giant scorpion, or.heaven forbid.godzilla. so anyway i got batteries and it does self test and the needle zeros. the scale on the meter reads from zero to .5 roentgens per hour. then a selector for x1, x10,x100. i googled whats a safe level and whats not, but they use different units. watched some utube videos and its amazing what is radioactive out there . new concrete , granite countertops, old luminescent gauges, even some dinnerware was glased with uranium in the 30s and 40s. you can even check your disposable furnace filters for the presence of radon. so far i havent found any giant radioactive mutant tractors. any idea what roentgen numbers are safe/unsafe? heres a pic of the unit

 

[drsportster]

Very cool item

 

[Andy Wickiser]

For just goofing around you want the CDV-700. It measures much lower levels including background and you can hear the individual clicks. It has a cabled GeigerMller probe with a shield that can be closed to differentiate beta and gamma. The one you bought is for relatively high level such as after a nuclear event. The CDV-700 can falsely read zero if the tube is swamped with high levels of radiation. I tried checking some granite field stones and didn't get much above background. Can get readings from smoke detectors and old luminous switches and dials containing radium.

<IMG SRC=https://i.postimg.cc/sXJp5Qcs/VictoreenCDV700.jpg>

 

[Doug - Iowa]

Here's mine, never tried to make it work. Come with the dosimeter charger but no dosimeter. Got it in a trade with some ham radio stuff.

Also have another yellow device, Vietnam era bailout VHF and UHF radio. Story goes these were too heavy for the pocket on the pilots jumpsuit, ususally when the parachute opened the shock ripped it out of the pocket and was lost. Never put batteries in it either, who knows who might come looking if it started transmitting.

Keep both on the bookcase in my office as curiosity items.

 

[Steve in VA]

The roentgen is pretty much a retired unit in lieu of Rem which normalizes biological hazard for various forms of radiation. The roentgen, or R, is gamma. For occupational workers the annual limit is 5 Rem while a Member of the Public is 0.5 Rem.

The instrument you have would measure gamma no alpha and beta only if it has a window associated with the detector.

Nice score.

 

[Richard G.]

Find an old army compass with the radium dial and check it.
You will be surprised.

 

[Steve in VA]

Here are a few Pocket Ion Chambers [PICs] that would use your charger. The PIC has an internal wire electrode that is moved across the view window by applying a charge from the battery in your charger. As exposed to ionizing radiation, the charge is dissipated and the wire moves across a scale visible inside the PIC. Pretty basic but suffers is roughly handled.

I had an old military chemical dosimeter that I donated to the Greenbriar for their bunker.

 

[Red Dave]

By the time you start to get a reading on that Geiger Counter, you are already over exposed.

That model was made to check if radiation has diminished enough to venture out of your bomb shelter during nuclear war.

The model with the external probe is the one that can detect radium dials on watches.

 

[Doug - Iowa]

Thanks, now I know what I am looking for. Several on eBay for a few bucks, I have to buy one to go along with my charger. Isn't that how one ends up with all this crap?

I have some WW2 vintage military radios that will probably show radioactivity due to luminescent dials.

 

[Geo-TH,In]

Radon Type of Radiation Emitted: Alpha Particles Half-life: 3.8 days Radon in the Environment Radon is a radioactive gas that results from the natural decay of uranium and radium found in nearly all rocks and soils. Elevated radon levels have been found in every state. Radon is in the atmosphere and can also be found in ground water.
After Uranium 238 decays produces radon gas. Uranium's final state is Lead. That's why lead is found in most drinking water.



The end-window type of a GeigerMller tube must be used to detect alpha particles, because they have a high capture cross-section and are easily stopped by any kind of solid material. A thin window is required to allow as many alpha particles as possible to pass through. In fact, alpha particles have a short range even in air, so ideally the tube window should be within a centimeter of the radiation source.

Radon collectors are charcoal. Charcoal traps radon. When you get enough radon a geiger counter with a tube will detect it.

The GeigerMller tube produces a pulse output which is the same magnitude for all detected radiation, so a Geiger counter with an end window tube cannot distinguish between alpha and beta particles. A skilled operator can use varying distance from a radiation source to differentiate between alpha and high energy beta particles.

I'm not 100% sure your type of geiger counter can measure alpha radiation. Limited to Beta and gamma. Your geiger counter has no external tube with a window.

Do more research and post back. I may be wrong.
Yours won't detect radon.

 

[sms]

About eight years ago I was pulled aside by airport security in Las Vegas. Only thing they checked was my shoes. Only thing I could think of was that I had been hiking in Moab and I set off a detector. Plenty of uranium in that area.

 

[tech4]

That looks like an old BC 348 receiver.

 

[K Effective]

As a worker in a nuclear facility, I wear passive dosimetry daily as well as electronic metrology. If we need to enter an area with measured dose rates above 10 milliRem per hour, we need a special briefing and to enter an area over 100 mR/hr, we need constant coverage.

As of last Wednesday, I had received 99mR industrial dose during 2022. Our utility limits us to 2000 mR and the NRC to 5000 mR each year (2Rem or 5Rem)

About 20 years ago, I routinely received 300+mR annually in the same job role, but we have improved, and I have younger coworkers who need to experience some of the work in the higher dose areas.

Our monitoring group reports that local residents receive about 360mR per year in background radiation without working on site. That varies on where you live, elevation, soils and rocks nearby, etc.

 

[old]

Many of the glow in the dark watch faces are radioactive. If you had that type of watch you where not allowed to have it on board the sub I was on

 

[JGayman]

Nice! I keep checking Ebay for a used CRM-114 but so far no luck.