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CDV700CLUB · The CDV 700 Club

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  • Members: 1088
  • Category: Physics
  • Founded: Oct 7, 1999
  • Language: English
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Holy COW!   Message List  
Reply Message #38251 of 38459 |
Re: Holy COW!

I had the deck marker in that heat sealed poly bag for about 3 months.

When I decided to sell it last week I opened the bag to take the photos and make
measurements.

That is when I tested the bag. Not much if any alpha outside the bag, but lots
of beta and some gamma.

I don't think that any Radon escaped the bag. It was all contained within.

Six days later I tested the bag with my thin window GM tube on my NCA General
Scaler Ratemeter Model RCR-1; very little radiation remains, probably due to
radio lead.

I suspect that the poly does take up Radon and holds it, probably not as
effective as activated carbon though.

I have some other disks also heat sealed in poly bags and when I get some time
to do so, I will experiment with those bags as well.

So, to keep these disks safe, it is best to heat seal them in poly bags. Zip
locks alone probably not good enough unless heat sealed.

Steve.


--- In CDV700CLUB@yahoogroups.com, "jsboggess@..." <jsboggess@...> wrote:
>
> Your discovery prompts many simple home experiments;
>
> 1. Looking for alphas with an PDR-56 alpha scintillator counter on the
OUTSIDE of the plastic bag to see if Radon or Radon daughters have diffused thru
the plastic...
>
> 2. Repeat the above alpha scintillator check on an unopened bag-encased deck
marker. I;d expect that alphas would not make it thru plastic, but I'm not sure
about Radon atoms...
>
> 3. Repeat the above alpha check on both sides of the bag, see the relative
alpha count on either side of the plastic.
>
> How long did you have the deck marker sealed inside the bag? I can see all
kinds of experimental fun here. Of course, if you have only 1 marker, there'll
be lots of reseals and waiting for equilibrium again.
>
> I have a PDR-56 and a plastic-wand-encased Ra-226 check source. The -56 ONLY
counts alphas, counts like a bansee on a WWII aircraft gauge if the glass is
removed, hardly nothing if glass is in place or if a piece of paper is between
-56 and the source. Hmmm, may have to investigate myself for creeping Rn
daughters,,,
>
> Jay Boggess
>
> Steve wrote;
>
>
> I am selling a deck marker on Ebay:
>
> Item 190630224674
>
> I keep them in heat sealed plastic bags. Well I cut open the bag that this
disk was in to test it. It measures ~16 mR/HR with a calibrated CDV700 standard
configuration with beta shield closed.
>
> Then I tested the bag.
>
> HOLY COW !
>
> I could hardly believe my eyes. With the beta shield open on the X1 scale it
pegged.
>
> On the X10 scale it registered ~1500-2000 CPM
>
> With the beta shield closed just barely on X1.
>
> I held it up to the light to see if there was any evidence of contamination.
It was clear as ever.
>
> The most likely culprit is Radon (Ra-222) that saturated the plastic.
>
> So leaving the bag open for a while, the readings over the next couple of days
decreased, at a rate that is consistent with Radon.
>
> I think that Radon had actually permeated the plastic poly bag to saturation,
and an equilibrium was established over the months that I had the disk heat
sealed in that bag.
>
> So, polyethene bags can serve as well if one whats to snag Ra-222 from a
radium cow.
>
> And what remains as the Ra-222 decays are the daughters.
>
> Steve
>
>
>
>
> ____________________________________________________________
> 53 Year Old Mom Looks 33
> The Stunning Results of Her Wrinkle Trick Has Botox Doctors Worried
> http://thirdpartyoffers.juno.com/TGL3141/4f22e8f1a6608796f91st05duc
>





Fri Jan 27, 2012 6:37 pm

steve_schoner
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Message #38251 of 38459 |
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I am selling a deck marker on Ebay: Item 190630224674 I keep them in heat sealed plastic bags. Well I cut open the bag that this disk was in to test it. It...
SRS
steve_schoner Offline Send Email
Jan 27, 2012
4:28 pm

Your discovery prompts many simple home experiments; 1. Looking for alphas with an PDR-56 alpha scintillator counter on the OUTSIDE of the plastic bag to see...
jsboggess@...
radiacfan Offline Send Email
Jan 27, 2012
6:12 pm

I had the deck marker in that heat sealed poly bag for about 3 months. When I decided to sell it last week I opened the bag to take the photos and make...
SRS
steve_schoner Offline Send Email
Jan 27, 2012
6:37 pm

Assuming it is Rn-222, which is the most likely candidate, the halflife is 3.82 days.  Using the rule-of-thumb of 1-e^lambda-t,  you'll reach 95% of...
Ken Sejkora
quickhatch44 Offline Send Email
Jan 27, 2012
7:15 pm

Hi Steve, Radon has an affinity for polyethylene. It will diffuse into it several mm. See...
robert8rpi Online Now Send Email Jan 30, 2012
6:55 pm
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