On 03/15/2017 09:42 AM, Mark Moulding wrote:
> On Tuesday, March 14, 2017 at 10:02:40 AM UTC-7, Paul Andrews wrote: >> >> What is your opinion of this one: >> http://www.ebay.com/itm/Open-source-Geiger-counter-kit-nuclear-radiation-GM-detector-tube-radiation-/161447070168?hash=item2596fec9d8:g:gFMAAOSwcu5UN4Pk Glass GM tube equals low sensitivity. The thick walls, necessary to withstand the partial vacuum, will stop most betas, what you're likely to encounter in the environment. Gamma ray sensitivity will be low but will be enough to detect the activity from a lantern mantle. To measure exposure, what you're really interested in, one needs a large volume energy compensated geiger tube or an ion chamber. An ion chamber is trivially easy to make - for years Victoreen sold an exposure meter, the chamber of which was a styrofoam cup coated on the inside with aquadag to make it conductive. A smoke detector is an ion chamber. A source is contained within the chamber. combustion products absorb ionizations, reducing the ion current and triggering the alarm. If you're interested in hearing clicks, the tube used in the old CDV-700 civil defense geiger counters will work. Very thin wall metal tubes. Best is a pancake probe. About $140 from Ludlum and others. Look guys, this fear of environmental radiation is getting far out of control. There is ZERO risk from anything radioactive in the environment unless you happen to eat the hand off a radium watch dial or an Am-241 source out of a smoke detector. Even then the risk would be so low as impossible to quantify. The old and discredited linear, no threshold theory that says that any amount of radiation is harmful is perpetuated because it has been monetized. Lots of people are making lots of money "remediating" low level radioactivity. The evidence is overwhelming that low level radiation is actually beneficial. No different than chemical toxins such as arsenic or zinc or chlorine. Vital trace elements but toxic in higher concentrations. This theory is called "radiation hormesis". Here is an article I wrote during the Fukushima accident that explains the difference. http://www.johndearmond.com/2011/04/23/fukushima-the-high-cost-of-the-lnt-theory/ A Geiger counter is a fun thing to have around if it is sensitive enough to detect anything. I carry a pocket unit with the pancake probe's window facing outward any time I go yard saleing, attend auctions or go to antique stores. I collect radioactive materials and I've hit some bonanzas I especially like to lay the counter on top of some radiophobe's granite countertop. The unit goes off-scale on the X1 scale. Granite is quite hot on the environmental activity scale. As I demonstrate on my nuke page that I already posted, so is wood ash from the fireplace. We need to nip this radiophobia in the bud and worry about something that matters. Like how many Nixie tubes Dalbor can make :-) John -- John DeArmond Tellico Plains, Occupied TN http://www.tnduction.com <-- THE source for induction heaters http://www.neon-john.com <-- email from here http://www.johndearmond.com <-- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0a81e938-2911-18cf-5ac6-5702bf8ddb3f%40neon-john.com. For more options, visit https://groups.google.com/d/optout.
