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 Greetings from Fremont, CA 
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Joined: Sat Dec 14, 2013 1:11 am
Posts: 118
I had to join in after seeing monitoring stations both above and below me in San Francisco and San Jose, and would be willing to put my Inspector Alert to work. I've been taking it with me daily on commutes to work, and to local bodies of water. The CPM I'm getting is significantly lower than those reported on your sites nearby though. For instance I just set it on a five minute timer outside an upstairs window and got only 32 CPM. While out commuting, it typically ranges between 35-55 CPM. The only things that have stood out were an area of decorative rocks in the front yard that read a steady 120 CPM, and a friend's glass vase colored with uranium. That was tens of thousands of CPM, and the uSv read over a five minute period indicated that you'd get the equivalent of a dental x-ray for every 4.3 hours you were right next to it. It was interesting putting different materials between the vase and the counter to block different particles and see the counts change. Anyway, I convinced him to get rid of it, or place it somewhere it couldn't fall and break where people wouldn't be near it. Stepping on a sliver of uranium doped glass would really not be cool at all.

I'll probably scrounge up a laptop and can leave it running 24/7 with breaks to change the battery and such. I've a few concerns though, namely..

Where is the best spot to position the counter? Affixing it near the roof would seem to be ideal, but the counter has warnings about the detector being exposed to direct sunlight or moisture. Is there some sort of shroud that'd be useful, but not diminish the count? What's ideal way to set up outdoors?

Also, I have been looking into getting both a liquid scintillation counter as well as a mass spectrometer to determine exact abundances of radionuclides in the ocean, wildlife, rainwater, anything I can get a sample of really, and a map could be pretty useful for that too. Would you fancy expanding what you've got here? I am so, so tired of reading about dying starfish or ocean animal migrations and people jumping to the conclusion that it must be radiation. First hand data observed from accurate instruments removes the need for all of this speculation right away, and that's why I like your site. :)


Sat Dec 14, 2013 2:32 am
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I got one of these today:
http://www.amazon.com/Holmes-HAP242-UC- ... r+purifier

My only counter at the moment is an Inspector Alert so I'm doing a background check in my house with the windows closed, but intend to put it outside tonight to gather some data following the recent spike reported by SF and the elevated levels in San Jose nearby. It's pretty smoggy and overcast out. Because the IA is a lot more sensitive, I'm expecting higher counts, but we'll see. Also, like the one recommended with the Raspberry Pi setup, this air purifier supports emitting some ozone to ionize the air it releases. Is this more or less useful for capturing radionuclides? I'm still new to all of this, but wouldn't a positively charged alpha particle be attracted to a negatively charged ozone particle?

Does anyone know if there are any message boards or resources for anyone looking to get a liquid scintillation counter? I see a few available on ebay or online, but it's hard to find reviews of them and I want to be sure I get one that suits my needs. Specifically one that can determine cesium from tritium and give me a better idea what radionuclides are detected, should I find any. Should I find any radionuclides in the tap water, I'll probably get a bunch of different bottled waters and start testing those to see which is safest.


Tue Dec 17, 2013 7:11 pm
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Joined: Mon Jan 28, 2013 7:40 pm
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Location: Illinois
:!: Do not put you Inspector with pancake GM tube up to the air filter while it is running. The suction might damage your pancake GM tube. I use a GMC-200 which uses a different tube, not pancake.

:arrow: I have not used/tested the ionize feature so I can not answer you.

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MY OUTSIDE RADIATION MONITORING STATION:
South Beloit, Illinois - GMC200 Outside on HEPA air purifier, ground level, facing West.
http://netc.com/chart/view.php?n=1%3AEB5A139C


Tue Dec 17, 2013 8:12 pm
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KingCobra wrote:
:!: Do not put you Inspector with pancake GM tube up to the air filter while it is running. The suction might damage your pancake GM tube. I use a GMC-200 which uses a different tube, not pancake.

:arrow: I have not used/tested the ionize feature so I can not answer you.


Thanks for the reply! My test today in my room yielded an interesting finding. A five hour average showed about 58 cpm, which was elevated based on what I see without an air purifier. However, realtime data from the counter shows 150 cpm now, indicating that levels rose to that point after initially being low. I have a few filters and will take some measurements without inserting them into the purifier, as well as a few measurements at other locations. Little high from what I was expecting.

Btw, the tube is about 1" from the suction, and I'm using the lowest setting. It does not seem all that dangerous to the Inspector.


Tue Dec 17, 2013 9:35 pm
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Ok, being setback from the filter like you mentioned and running on low might be ok.

I own an InspectorEXP and a Mazur 9000, both the pancake GM units as you know. You might really enjoy using the GMC-200 on that purifier while on high like I do. For $85 that GMC-200 is a good deal, I own many of them. They are durable too but some people have received a defective unit so, I am thankful that I never have had a problem though. My outside unit come April will make a year that GMC-200 has been outside running 24/7.

If you put that purifier in your basement and run it on high for 24 hours and then remove the filter and test the backside of the filter with your Inspector for highest CPM seen, I can give you an idea of what your radon level is in the basement. I know this, because I have done it with mine and compared it to the radon readings from my digital radon only detector.

_________________
MY OUTSIDE RADIATION MONITORING STATION:
South Beloit, Illinois - GMC200 Outside on HEPA air purifier, ground level, facing West.
http://netc.com/chart/view.php?n=1%3AEB5A139C


Tue Dec 17, 2013 10:29 pm
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Heh, not many folks in CA have a basement, and I am no exception. This reading was taken in a second floor bedroom, so it would be surprising if radon was that much of a factor. Would you share your CPM readings when you were looking for radon?

I took out a new filter and set the Inspector on it, and got a normal background reading of ~30 CPM.

Just got back from putting my GC in a bag in front of the filter on my air purifier on my roof. We get a good amount of wind, so I'm expecting a good reading. Nighttime temperatures don't get near the bottom end of its operating temperature and there is supposed to be 0% precipitation so I should be good to go. Now to find an audio cable long enough to reach out there so I don't have to keep going out to check it. Initial readings after 10 minutes or so are about 120cpm but that's with a clean filter.

KingCobra wrote:
Ok, being setback from the filter like you mentioned and running on low might be ok.

I own an InspectorEXP and a Mazur 9000, both the pancake GM units as you know. You might really enjoy using the GMC-200 on that purifier while on high like I do. For $85 that GMC-200 is a good deal, I own many of them. They are durable too but some people have received a defective unit so, I am thankful that I never have had a problem though. My outside unit come April will make a year that GMC-200 has been outside running 24/7.

If you put that purifier in your basement and run it on high for 24 hours and then remove the filter and test the backside of the filter with your Inspector for highest CPM seen, I can give you an idea of what your radon level is in the basement. I know this, because I have done it with mine and compared it to the radon readings from my digital radon only detector.


Tue Dec 17, 2013 11:14 pm
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Peak readings for the evening were around 260 CPM, with a low of 190. Still looking for more of a permanent outdoor installation that can withstand the weather year round. Anyone have a pic of the EPA setups?


Wed Dec 18, 2013 3:11 am
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Morellio wrote:
Peak readings for the evening were around 260 CPM, with a low of 190. Still looking for more of a permanent outdoor installation that can withstand the weather year round. Anyone have a pic of the EPA setups?


From within this link below there is a button/link to start a slideshow that has pictures showing their units.
http://www.epa.gov/radnet/about-radnet/science-note.html

_________________
MY OUTSIDE RADIATION MONITORING STATION:
South Beloit, Illinois - GMC200 Outside on HEPA air purifier, ground level, facing West.
http://netc.com/chart/view.php?n=1%3AEB5A139C


Wed Dec 18, 2013 12:37 pm
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Joined: Mon Jan 28, 2013 7:40 pm
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Location: Illinois
Morellio wrote:
Heh, not many folks in CA have a basement, and I am no exception. This reading was taken in a second floor bedroom, so it would be surprising if radon was that much of a factor. Would you share your CPM readings when you were looking for radon?


Although my geiger counter could have been detecting more than just radon, the filter showed a rapid decay right after I took the filter off the purifier so it was likely only radon. It had just finished raining outside too which is when I always detect a rise in radiation levels in the basement. Since the digital radon only detector takes days to sample the air and come up with a reading, it is very likely that the reading seen (4.6 pCi/L) is lower than what the real-time level was at the time of filter testing with my InspectorEXP.

I have installed a radiation mitigation pump and have been able to get my basement level down to below 2 pCi/L. As you know the EPA says anything over 4 pCi/L is where action needs to be taken to correct the problem.

Image

_________________
MY OUTSIDE RADIATION MONITORING STATION:
South Beloit, Illinois - GMC200 Outside on HEPA air purifier, ground level, facing West.
http://netc.com/chart/view.php?n=1%3AEB5A139C


Wed Dec 18, 2013 2:01 pm
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Joined: Sat Dec 14, 2013 1:11 am
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Wow thanks for the information and pic! I've done a lot of reading after becoming aware of this topic, and seeing real world examples always helps add more data points for comparison and how to take/interpret measurements. I still want to get my hands on a liquid scintillator, gas chromatograph, and mass spec though to identify exactly the identity and quantity of any given radionuclide. Anyone got a spare $750,000 laying around? :D

KingCobra wrote:
$2
Morellio wrote:
Heh, not many folks in CA have a basement, and I am no exception. This reading was taken in a second floor bedroom, so it would be surprising if radon was that much of a factor. Would you share your CPM readings when you were looking for radon?


Although my geiger counter could have been detecting more than just radon, the filter showed a rapid decay right after I took the filter off the purifier so it was likely only radon. It had just finished raining outside too which is when I always detect a rise in radiation levels in the basement. Since the digital radon only detector takes days to sample the air and come up with a reading, it is very likely that the reading seen (4.6 pCi/L) is lower than what the real-time level was at the time of filter testing with my InspectorEXP.

I have installed a radiation mitigation pump and have been able to get my basement level down to below 2 pCi/L. As you know the EPA says anything over 4 pCi/L is where action needs to be taken to correct the problem.

Image


Wed Dec 18, 2013 2:22 pm
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