All Forums  GQ Electronics Forums  2.GQ Geiger Muller Counter  GMC-600+ Elevated Reading from Static or Radon?

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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by jun192022[/i] [br]TL;DR: I'd like someone to run an experiment to prove that it is possible to induce a static electric charge on a plastic bubble mailer envelope (such as through rubbing with a plastic grocery bag or peeling packing tape off its surface) which is significant enough to attract radon decay products and induce an elevated reading on a GMC-600+. I currently no longer have the Geiger counter mentioned below in this post. Thanks guys! After purchasing a GMC-600+ for a university lab, I have been confused about an elevated radiation reading from the USPS Priority Mail bubble mailer envelope the Geiger counter came in. When I put the Geiger counter up to the envelope, the reading went up to about 155 CPM (0.44 uSv/hr), compared to about 40 CPM (0.11 uSv/hr) for background and 110 CPM for a granite countertop. If I held up a piece of paper between the Geiger counter and envelope, the measured radiation went down to around 130 CPM. These readings were repeated 3 separate times 15-30 minutes apart, but I forgot to record the readings at the time. When I retested the envelope a day later, I was not able to detect elevated radiation levels. I have been a bit confused and concerned about possible radioactive contamination on the envelope falling off and spreading elsewhere. However, I also read that static charges may temporarily induce false radiation readings for pancake Geiger counters, as noted with plastic sandwich bags: https://hps.org/publicinformation/ate/q10421.html. I am wondering whether there was a static charge on the envelope, given that 1) I had put the envelope inside a plastic grocery bag earlier that day and it could have rubbed against the plastic bag, and 2) the envelope had been taped together and I had peeled some packing tape off its surface before taking the Geiger counter out. Questions: 1) Would anyone here be able to 1) induce a static charge (either through rubbing with a plastic bag or peeling off tape) on a plastic bubble mailer envelope (preferably a USPS Priority Mail bubble mailer envelope), wait awhile for radon decay products to settle on its surface, then replicate an elevated radiation reading using a GMC-600+, and 2) show that the elevated reading persists when a sheet of paper is inserted between the Geiger counter and envelope? I no longer have access to the original envelope or Geiger counter (it was purchased for a university lab but I am no longer working in that lab), so any help to confirm that I likely did not encounter radioactive contamination would give me some peace of mind and be much appreciated! - This is the type of envelope: https://store.usps.com/store/product/shipping-supplies/priority-mail-flat-rate-padded-envelope-P_EP14PE - Here's a similar experiment which was able to induce a static charge on a balloon, attract radon daughters to the balloon surface, and reproduce elevated radiation readings on a Geiger counter: https://www.youtube.com/watch?app=desktop&v=tl5oHojFzXc&ab_channel=Matthiasrandomstuff 2) Has anyone else had similar experiences with static electrical charges affecting GMC-600+ readings, and if so, with what kinds of items? 3) How concerned should I be about this measured radiation level if there were some kind of contamination? If my readings were accurate, I calculated the potential extra yearly radiation above background as: (0.44-0.11)*24*365/1000 = 2.89 mSv/yr. - One one hand, this is below the 5 mSv/yr occupational limit for minors and pregnant women: https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/full-text.html#part020-1207 - On the other hand, it is above the 1 mSv/yr NRC exposure limit for members of the public: https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/full-text.html#part020-1301 - In the worst-case scenario of contamination leading to chronic radiation exposure, an online predictor of cancer risk from radiation exposure (https://www.xrayrisk.com/calculator/calculator-recurring-studies.php) calculated that a female chronically exposed to 2.63 mSv/yr above background every year of life from age 1 to 77 (expected lifetime in US) could have a 2.866293% (1 in 35) additional lifetime cancer risk. This seems a bit high when compared to the lifetime risk of dying in a car accident of 1 in 93 (https://injuryfacts.nsc.org/all-injuries/preventable-death-overview/odds-of-dying/data-details/)? [/quote]    Insert an Image File Check here to include your profile signature.