Comments on: Geez, I Hate To Pick on a Couple of Kids, But the MIA Put Them Up to This http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/ Everything you need to know about the granite/Radon/radiation issues. For more info, go to forum.solidsurfacealliance.org Sun, 09 Jan 2011 21:09:16 +0000 http://wordpress.org/?v=2.8.4 hourly 1 By: Administrator http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/comment-page-1/#comment-90 Administrator Wed, 03 Sep 2008 23:03:44 +0000 http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/#comment-90 Hmmm, I see your point on the timed reading, but I would think that 16 cpm would be way too low for background radiation. Here it is 60 cpm or around 5 to 6 uR/hr from a scintillator. Our shop building, concrete walls, floor and roof, has around 7 uR/Hr background. Here is a map of the US showing Gamma radiation http://energy.cr.usgs.gov/radon/usagamma.gif Nothing over 8.5 shown on the map. No doubt there are places like that that I don't know about. I would say that they didn't understand the meter and ran a timed test out of ignorance. Sixteen is pretty high in a home and they reported the so called "radioactive" food to be lower than their "alone" readings. Those readings are consistent with a fairly low level granite countertop under that towel. An accurate meter would be nice. One of our researchers took one of my ideas, using dosimeter film badges, and has ordered some to try out at a pretty hot granite countertop she found in San Jose CA. There is a Bicron Analyst for sale with both a pancake and scintillator probe. Not sure if this is accurate enough for this type of work, might have it confused with another Bicron meter. Dr. Llope is continuing to say that regardless of the meter's accuracy, only a few percent of the radiation will be counted any way. Could you take his Gamma Spectrometry results and compute an exposure at different ranges? Will having the CPM and the isotope make for an accurate uR/hr calculation? Hmmm, I see your point on the timed reading, but I would think that 16 cpm would be way too low for background radiation. Here it is 60 cpm or around 5 to 6 uR/hr from a scintillator. Our shop building, concrete walls, floor and roof, has around 7 uR/Hr background. Here is a map of the US showing Gamma radiation

http://energy.cr.usgs.gov/radon/usagamma.gif

Nothing over 8.5 shown on the map. No doubt there are places like that that I don’t know about.

I would say that they didn’t understand the meter and ran a timed test out of ignorance. Sixteen is pretty high in a home and they reported the so called “radioactive” food to be lower than their “alone” readings. Those readings are consistent with a fairly low level granite countertop under that towel.

An accurate meter would be nice. One of our researchers took one of my ideas, using dosimeter film badges, and has ordered some to try out at a pretty hot granite countertop she found in San Jose CA.

There is a Bicron Analyst for sale with both a pancake and scintillator probe. Not sure if this is accurate enough for this type of work, might have it confused with another Bicron meter.

Dr. Llope is continuing to say that regardless of the meter’s accuracy, only a few percent of the radiation will be counted any way. Could you take his Gamma Spectrometry results and compute an exposure at different ranges? Will having the CPM and the isotope make for an accurate uR/hr calculation?

]]> By: Gary http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/comment-page-1/#comment-89 Gary Wed, 03 Sep 2008 12:31:15 +0000 http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/#comment-89 If the meter was set for uR/hr, then the one minute count would have been unnecessary, and the reading would have varied up and down around the average dose rate. Since the readings started at zero and went up till stopped, it was set for CPM. BTW it would be nice to have a meter that would average the dose rate over a one minute period and report it in uR/hr, but they are usually pretty expensive. If the meter was set for uR/hr, then the one minute count would have been unnecessary, and the reading would have varied up and down around the average dose rate. Since the readings started at zero and went up till stopped, it was set for CPM. BTW it would be nice to have a meter that would average the dose rate over a one minute period and report it in uR/hr, but they are usually pretty expensive.

]]> By: Administrator http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/comment-page-1/#comment-76 Administrator Fri, 29 Aug 2008 17:02:02 +0000 http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/#comment-76 I am afraid they were trying to "score points" for the MIA, or were doing the best they could with the limited education and experience available to them. Been there, done that. Another point is that the MIA should have known this video was quite misleading. Why then, did they use it if they had anything else? I am afraid they were trying to “score points” for the MIA, or were doing the best they could with the limited education and experience available to them. Been there, done that.

Another point is that the MIA should have known this video was quite misleading. Why then, did they use it if they had anything else?

]]> By: Administrator http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/comment-page-1/#comment-75 Administrator Fri, 29 Aug 2008 17:00:24 +0000 http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/#comment-75 No, we aren't really comparing apples to oranges. I brought up the Niagara gold uR/hr because THAT paticular meter was used to measure a slab that we had a known value for, I was pointing out that our meter was reading the same uR/hr as the one they used. The fact of the matter is they didn't mention what the meter was set on. However, in my research, 16 cpm is about one quarter of what should be expected in their area according to the background radiation maps. From that fact, it is obvious they had the meter set on uR/hr, unless they had some really radioactive materials. Our only point in the article was that the majority of the items they claimed were "radioactive" were in fact lower than background (their "alone )measurement. My assumption since they didn't show the "alone" measurement, that it was taken on the towel covered countertop. From a "16" reading including background, which is pretty average for a low level granite countertop material, and their lower readings, I assume the lowest reading is the true background although our vidoes of measuring bananas and potatoes did not show any radiation at all. No, we aren’t really comparing apples to oranges. I brought up the Niagara gold uR/hr because THAT paticular meter was used to measure a slab that we had a known value for, I was pointing out that our meter was reading the same uR/hr as the one they used.

The fact of the matter is they didn’t mention what the meter was set on. However, in my research, 16 cpm is about one quarter of what should be expected in their area according to the background radiation maps.

From that fact, it is obvious they had the meter set on uR/hr, unless they had some really radioactive materials.

Our only point in the article was that the majority of the items they claimed were “radioactive” were in fact lower than background (their “alone )measurement.

My assumption since they didn’t show the “alone” measurement, that it was taken on the towel covered countertop. From a “16″ reading including background, which is pretty average for a low level granite countertop material, and their lower readings, I assume the lowest reading is the true background although our vidoes of measuring bananas and potatoes did not show any radiation at all.

]]> By: Gary http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/comment-page-1/#comment-73 Gary Fri, 29 Aug 2008 16:35:20 +0000 http://solidsurfacealliance.org/blog/2008/08/27/geez-i-hate-to-pick-on-a-couple-of-kids-but-the-mia-put-them-up-to-this/#comment-73 It is difficult to compare apples and oranges. They are doing a 1 minute count and posting results in counts per minute (CPM). Your surveys were done with a meter reporting microRads per hour (uR/hr). All GM tubes start with CPM. Those that read out in mR/hr (or uR/hr) use an internal correction factor. This can vary wildly. For example a Ludlum 44-9 (the common pancake probe) has a sensitivity of 3300 CPM/mR/hr (137Cs gamma). An energy compensated meter such as the Ludlum 2401-EC2A has a sensitivity of 120 CPM/mR/hr (137Cs gamma). If you go to a meter with a scintillation probe, Ludlum 2401-P, the sensitivity can be as high as 120CPM/uR/hr! (120,000 CPM/mR/hr137Cs gamma). A 2" by 2" Sodium Iodide scintillator (Ludlum 44-10) has a sensitivity of 900 CPM/uR/hr (900,000 CPM/mR/hr. If this gets a bit confusing, we can take a shortcut that will have some limited value. We can compare reading from different meters in the same background. I have a meter with a pancake probe, calibrated in CPM and a meter with a 1" by 1" NaI scintillator calibrated in uR/hr. (both to Cs-137) In the same background, one reads 50 CPM and the other reads 15 uR/hr. Each meter has a different response curve, so the relationship is one point only(cannot be scaled up). But, roughly, their '16' is 16 CPM which is a really low background 'about' 5 uR/hr, and their '26' 'about' 8 uR/hr. So...if there was a granite countertop involved, it is very very low level. They could have made more points for MIA by showing it. It is difficult to compare apples and oranges. They are doing a 1 minute count and posting results in counts per minute (CPM). Your surveys were done with a meter reporting microRads per hour (uR/hr). All GM tubes start with CPM. Those that read out in mR/hr (or uR/hr) use an internal correction factor. This can vary wildly. For example a Ludlum 44-9 (the common pancake probe) has a sensitivity of 3300 CPM/mR/hr (137Cs gamma). An energy compensated meter such as the Ludlum 2401-EC2A has a sensitivity of 120 CPM/mR/hr (137Cs gamma). If you go to a meter with a scintillation probe, Ludlum 2401-P, the sensitivity can be as high as 120CPM/uR/hr! (120,000 CPM/mR/hr137Cs gamma). A 2″ by 2″ Sodium Iodide scintillator (Ludlum 44-10) has a sensitivity of 900 CPM/uR/hr (900,000 CPM/mR/hr.

If this gets a bit confusing, we can take a shortcut that will have some limited value. We can compare reading from different meters in the same background. I have a meter with a pancake probe, calibrated in CPM and a meter with a 1″ by 1″ NaI scintillator calibrated in uR/hr. (both to Cs-137)

In the same background, one reads 50 CPM and the other reads 15 uR/hr. Each meter has a different response curve, so the relationship is one point only(cannot be scaled up).

But, roughly, their ‘16′ is 16 CPM which is a really low background ‘about’ 5 uR/hr, and their ‘26′ ‘about’ 8 uR/hr. So…if there was a granite countertop involved, it is very very low level. They could have made more points for MIA by showing it.

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