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I know this isn't about hunting (well, not game animals, anyway), but some of you guys seem smart enough to be able to offer some intelligent discussion on this subject, so that's why I'm posting it here. Could I get some serious discussion about tritium sights and cancer? I've seen the topic touched on, but only briefly. Can regular, daily carry of a gun with tritium sights cause cancer? I know the radiation is low, but I don't know how low. Also, I know there are different types of radiation (gamma, alpha, et cetera), but I don't know what type tritium produces and/or if it is harmful. Thoughtful comments will be appreciated. Thanks. Russ ------------------ | ||
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I just found this article. === Tritium http://128.165.46.15/tritium.html Watches containing tritium paint have been available to the general public (the possession, use, and transfer of such timepieces without a license) in the U. S. since 1961. Tritium (Hydrogen, H-3) is a pure beta emitter, decaying to Helium He-3 (stable) with a half life of 12.33 years. The 18.6 keV (max) beta can be stopped by a piece of paper and is biologically not very hazardous. Tritium is made in a high neutron flux reactor, by bombarding Lithium-6 (naturally occurring) with neutrons. The last U. S. high neutron flux reactor at Savannah River was shut down in 1988. Medical isotopes that must be produced by neutron activation are made in Canada at Chalk River or in Europe. It will not be until the first half of the next decade before there will be a domestic source of high flux neutrons. Modern watches with tritium hands will often have a very small label �T� or �T 25� or �T<25� on the watch face below the numeral 6 position. 25 refers to 25 mCi (milliCurie). One Curie (Ci) represents the amount of radioactive material that has the same number of disintegrations per second as one gram of Radium. This is now defined as 3.7 x 10 to 10th power disintegrations per second. The S. I. unit for activity is the Becquerel (Bq), defined as one disintegration per second.
The tritium gas filled, phosphor (scintillator) coated, borosilicate glass capsule used in Luminox watches (http://www.luminox.com) was patented by Texas Instruments. The patent was applied for in 1978 and granted in 1981. See the patent in the IBM U. S. patent database at http://www.patents.ibm.com/details?patent_number=4273398 The name �Traser� was registered for this device in 1978: http://www1.uspto.gov/tmdb/index.html Texas Instruments did not mass produce the Traser. This fell to mb-microtec. In 1983, mb-microtec ag (Niederwangen, Switzerland), through their U. S. distributor mb-microtec inc (North Tonowanda, NY), registered a 1000 mCi radioactive sealed source, to be used as a UV light source for US Navy research at Port Hueneme, California, with the Nuclear Regulatory Commission. See (requires Acrobat Reader): http://www.hsrd.ornl.gov/nrc/ssdr/04460101.pdf Mb-microtec registered various radioactive sealed sources with up to 50,000 mCi for various (licensed) use with the NRC in 1984. See: http://www.hsrd.ornl.gov/nrc/ssdr/04460102.pdf In 1993, mb-microtec filed a petition with the NRC to allow gaseous tritium light sources (GTLS) with 25 mCi or less in watches to be regulated in the same manner as 25 mCi tritium paint watches. This was approved in March of 1998. See http://www.nrc.gov/NRC/COMMISSION/SECYS/secy1997-028/1997-028scy.html http://www.nrc.gov/NRC/COMMISSION/SECYS/1998-060scy.html The Richard Barry Marketing Group (RBMG) of River Vale, New Jersey, has marketed watches with GTLS markers, initially under the microtec label, since 1989. The watches are now sold under the name Luminox (http://www.luminox.com). These watches were positioned at the $200 price point. In 1999, Luminox will be offering Swiss-made, sapphire crystal, stainless steel watches, and later, titanium watches. In 1996, mb-microtec registered radioactive sealed sources for watches containing up to 100 mCi with the Nuclear Regulatory Commission. See (requires Acrobat Reader): http://www.hsrd.ornl.gov/nrc/ssdr/04460103.pdf Note that in the NRC text there is reference to GTLS watches containing up to 200 mCi. These 200 mCi sources were used for permanent illumination of LCD watches. Other uses of GTLS are found in compasses, thermostats, and gun sights. Improvements in design have allowed excellent luminosity in watches with 25 mCi. Presumably this is what prompted the consumer version of analog GTLS watches.
A wearer of a radium-dialed watch will receive a gonadal dose of not more than 4 mrad/yr. This is to be compared to the natural radiation dose of 100-300 mrad/yr. A NY-LA flight will give a dose of about 1 mrad. The wearer of a metal-backed Tritium dialed watch receives a much lower dose: about 0.03 mrad/yr. The dose from GTLS watches should be significantly lower than 0.03 mrad/yr because the Tritium is sealed in glass capsules. The rad has dimensions of energy absorbed per unit mass, and is equal to 100 ergs/gram. The S. I unit is the Gray (Gy) and is equal to 1 Joule/kilogram. 1 rad = 1 cGy (centiGray). See �Medical Effects of Ionizing Radiation�, 2nd ed., Fred Mettler and Arthur Upton, W. B. Saunders, Philadelphia, 1995, chpt. 2, �Sources of Radiation Exposure�, p. 42. Tritium is a pure beta emitter, with a beta range of 6 mm in air, 0.0052 mm in water. Thus, the beta particles cannot even penetrate the dead layer of the skin, which is 0.07 mm thick. The danger from Tritium comes from ingestion or absorption of Tritium through the skin. The beta particles from a Tritium decay within the body can in fact damage cells. See: "Tritium exposure from plastic case watches", The Lancet, Vol 343, No. 8889, 8 Jan 1994. Bruce Lulu ------------------ | |||
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quote: Well... hello, Ms. Link. I received an immediate response to my E-mail to Dr. Lulu. Our exchange follows. === Mr. Lulu: I was doing some online research about whether tritium sights, on a gun You devoted a majority of your report to the wearing of wristwatches Thank you for taking the time to read this. I'll hope to hear from you Respectfully, Russell E. Taylor === The risk of tritium marked wristwatches with plastics backs is due to the tritium gas diffusing through the skin. That risk is exceeding small and not worth worrying about. Gunsites are not in continued direct contact with the skin and therefore pose no risk whatever. However, I would caution against eating any broken tritium gunsites. (<- joke) Bruce Lulu, Ph.D. === Dr. Lulu: I'll try not to eat any gunsights. I suspect, however, that if I do... something went drastically wrong on my part and some perp on the street has fed them to me. Thanks, Doc. Russ === As for retention straps, the gun in question (my PT945) has one of those cheesy nylon holsters with the magazine pouch in front. It has a retention strap, per se, but the thought occured to me to add a thin strip of lead -- or, per Dr. Lulu's comments and yours, I could just add a strip of leather to the inside of the retention strap. While I don't carry the PT945 regularly, but my PA-63 I "do" carry somewhat regularly... and in a location where I'd rather not get cancer, if you get my drift. Thank you for the reply. Russell E. Taylor [This message has been edited by Russell E. Taylor (edited 02-28-2002).] | |||
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<Constance> |
He is even less woried about the effects than I am. I would still cover the glow of the sites for tactical reasons. | ||
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Don't neglect to visit Connie's website. | |||
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quote: As they say, "been there, done that, got the T-shirt." Battle scars too. The woman does know what she's talking about, though. Ms. Link: Yes, with respect to tactical concerns, the sights are covered when the guns are holstered. I have suitable holsters for both guns (the PT945 with the P-T Night Sights, and my PA-63 with the AO Pro-Express Big Dot sight set). Good day. ------------------ | |||
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<jeremy w> |
Wouldn't getting say, one x-ray, equal wearing the stuff on you for a long time? | ||
<abnrigger> |
I think some folks get Tritium confused with Radium that used to be used for the same purpose and is dangerous. | ||
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I second abnrigger's comment about radium. Way back, if I remember my high school biology, the lumenous numbers and hands on watches were hand painted using radium based paint. The people doing the painting had the habit of wetting the brushes in their mouth to keep the point sharp. There was an increase of mouth and tongue cancer in that group. I doubt there was enough exposure to the watch wearers to be of concern. Jeff ------------------ | |||
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