Geiger Counter

[griffe017]

Hey, I got a question about geiger counters. I just ordered one to help me in testing for this granite counter top radiation craze (I am a radon tester currently). Anyways I had heard there are ways to block our certain radiation for showing up on your geiger counter. I am only interested in beta and alpha radiation because radon does not release substantial enough amount of gamma radiation to be harmful. I am wondering if there is any way i can block out gamma radiation from showing up on my geiger counter so i can find the source of the radon on the counter top. 
Thanks.

[Cathy]

What kind of geiger counter did you order? Does it have a separate probe?

[griffe017]

I bought the Inspector, it does not have a probe.

[HydroDave63]

I bought the Inspector, it does not have a probe.

Wrong tool for the job. How much are you willing to spend for good alpha-beta measurement?

[dinutt]

   just thought I would try to help. it is analog, digital ,how  sensitive instrument to the types etc and it must be hand held ? maybe you could use a shield  of aluminum or something shallow to see if it changes and it must read in cpm so maybe some subtraction process from bkg. not quite sure but there must be  alot of searches you could do or check with the manufacturer of this model you purchased.good luck !! not sure if i confused you more or helped in a small way
keep us posted .......
Di

[Cathy]

Okay, I think it actually has a built in pancake type probe. If you use shielding to block the gamma, you will also block the beta and alpha. You need to baseline the gamma and then subtract it from your readings. Use a process of elimination. Take un unshielded reading first, then place a shield that blocks the alpha/beta (something plastic like maybe a thick credit card), this second reading subtracted from the first will give you gamma. To differentiate alpha, place a sheet of paper between the probe and the surface and this reading gives you beta/gamma only. With those readings you should be able to calculate each type by a process of elimination. To truly be exact you would need an alpha only meter also. I am not sure what the efficiency for your meter is for alpha, typically GMs are pretty low. This also factors in for your alpha count.
There is a lot of knowledge in this forum. You guys feel free to jump in and explain it better!

[HydroDave63]

Okay, I think it actually has a built in pancake type probe. If you use shielding to block the gamma, you will also block the beta and alpha. You need to baseline the gamma and then subtract it from your readings. Use a process of elimination. Take un unshielded reading first, then place a shield that blocks the alpha/beta (something plastic like maybe a thick credit card), this second reading subtracted from the first will give you gamma. To differentiate alpha, place a sheet of paper between the probe and the surface and this reading gives you beta/gamma only. With those readings you should be able to calculate each type by a process of elimination. To truly be exact you would need an alpha only meter also. I am not sure what the efficiency for your meter is for alpha, typically GMs are pretty low. This also factors in for your alpha count.
There is a lot of knowledge in this forum. You guys feel free to jump in and explain it better!

, good explanation. That's why I asked his budget...if he wants to detect alphas for novelty or demonstration purposes, there is sheet scintillator material available for cheap  http://cgi.ebay.com/24X24-CM-Sheet-of-radiation-Scintillator-Phosphor_W0QQitemZ160253175974QQihZ006QQcategoryZ53154QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

If he wants to make this some sort of adjunct to the radon business.... http://cgi.ebay.com/LUDLUM-MODEL-43-5-ALPHA-PROBE-NO-QUESTIONS-RETURN-WARR_W0QQitemZ7605225705QQihZ020QQcategoryZ58289QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247  and a Ludlum Model 2 should be fine

[griffe017]

Hey guys thanks for the advice, yeah it does have a built in probe which is why I picked this model so i can just slide it along the granite. Anyways Cathy that is the kind of thing I was talking about, blocking out various radation. I will look into what you posted Hydro, thanks for the help!

[griffe017]

Yeah I like that Model 43-5 Hydro, It is mainly for this latest counter top scare that has popped up. I have other measuring devices that i have used for the last 15 years to monitor radon but those wont tell me specifically where it is coming from like a geiger meter or that Model 43-5. And in response to your first question I do have a good budget, what did you have in mind.

[griffe017]

Well that is the thing, it is funny as hell that the media broke this story as almost all building materials can potentially have radon in them. I wonder what the radon count of bricks is (as brick is just heated shale and soil). Now that would be funny if everyone started freaking out over brick homes!

[Limited Quanity]

We just had an engineer this year with 20 mrem on his TLD after the qtr read.  No RWP entries to speak of and no ED dose.  During the investigation it was discovered he had new kitchen tiles installed several months back and that's where he threw his work lanyard after work and weekends up on the counter.  He brought a tile into work and it was about 4000 cpm direct frisk, if I remember right.  It was gamma spec'd so that he could take it home.  I don't really remember if anything was put out site wide about it, just to inform folks.  Broadzilla or Roll Tide might remember if it was or not, guess I've slept since then.

[SloGlo]

Yeah I like that Model 43-5 Hydro, It is mainly for this latest counter top scare that has popped up. I have other measuring devices that i have used for the last 15 years to monitor radon but those wont tell me specifically where it is coming from like a geiger meter or that Model 43-5. And in response to your first question I do have a good budget, what did you have in mind.

iffeni wuz you, i'd go to ludlums.com, the web site for ludlum instruments.  they make good products.  they have a very professional staff who is adept at email or phone consultation.  they will get you dialed in for good instrumentation for what you're trying to do.

butt, i gotta ask... why don't you tent an area on a granite countertop and install your normal filter inside?  you could have another going outside the tent, and away from the kitchen for comparative purposes.  then you'd have a client specific report that would be correct to your applicable licensing and lab reporting.  jist a question..........

[NJ]

  This sounds like a great scam for laid off techs but how are you gonna source check your instrument.  I'm game!

[Fermi2]

We just had an engineer this year with 20 mrem on his TLD after the qtr read.  No RWP entries to speak of and no ED dose.  During the investigation it was discovered he had new kitchen tiles installed several months back and that's where he threw his work lanyard after work and weekends up on the counter.  He brought a tile into work and it was about 4000 cpm direct frisk, if I remember right.  It was gamma spec'd so that he could take it home.  I don't really remember if anything was put out site wide about it, just to inform folks.  Broadzilla or Roll Tide might remember if it was or not, guess I've slept since then.

I remember when that happened but so far as I know there was no bulletin on it. Nights is KILLING ME!!!

Mike

[griffe017]

there are several reasons slo! But I am to tired to list them all. Anyways thanks for all the help guys I got a game plan now!

[HydroDave63]

This sounds like a great scam for laid off techs but how are you gonna source check your instrument.  I'm game!

OK...I'll frisk NJ !

[SloGlo]

OK...I'll frisk NJ !

yinz kin have joisey.  aisle take hawaii

[NJ]

I told you all there was a need for techs,,you guys ready to form that company??

[NJ]

Hey were did that post go just in front of this one?

[Al Gerhart]

Hey were did that post go just in front of this one?

My fault NJ, I didn't read all the rules before posting.  Not supposed to recruit on the forums. 

My bad.   I gotta go read the rules so I don't do anything else.

[RedOrchid]

Well that is the thing, it is funny as hell that the media broke this story as almost all building materials can potentially have radon in them. I wonder what the radon count of bricks is (as brick is just heated shale and soil). Now that would be funny if everyone started freaking out over brick homes!

Yep.  Granite, concrete, paint... anything containing trace amounts of radium, which decays into radon.

[RedOrchid]

Hey, I got a question about geiger counters. I just ordered one to help me in testing for this granite counter top radiation craze (I am a radon tester currently). Anyways I had heard there are ways to block our certain radiation for showing up on your geiger counter. I am only interested in beta and alpha radiation because radon does not release substantial enough amount of gamma radiation to be harmful. I am wondering if there is any way i can block out gamma radiation from showing up on my geiger counter so i can find the source of the radon on the counter top. 
Thanks.

To answer this question regarding separation of alpha-beta from gamma in your readings, I'm partially sure this will work but I'm used to dealing with specific instruments so no promises.

Do whatever you're going to do to get something to count.  Then place a couple sheets of aluminum between the source and the instrument.  What you read then is your gamma radiation level.  Subtract this number from the number you get without the aluminum, and that's your alpha-beta radiation level.

[SloGlo]

Yep.  Granite, concrete, paint... anything containing trace amounts of radium, which decays into radon.

bricks is hot four radium/radon.  avery time i'm ona demo job, 'n geli some bricks, radium issa primary id'd isotope.

[N K Asokan]

Why don't you try a guard counter, which can reject gamma and back ground radiation based on co-incidence principle.  With suitable geometry, I think, it should work