Every now and then the radiation of mantles pops up. This weekend I finished or started to make a web page about my measurements so please check out my new radiation web page (< link). I made a new table of all my measurements. It would be nice to get more measurement from other people and other mantle brands. So if you want to share your data send me a excel file please. I have not included safety as to the point what level is safe and what not. I am not an expert and I don't want to get claims of people doing stupid things with mantles. I also am looking for additional parts for a DOM 410 radiation meter set. Please contact me if you have such a set or know where to find parts, military surplus is the only "corner" I know. Many thanks,
Nice list. I have a few questions. 1) how far away was the detector from the mantles? Was it the same in every case? 2) did you use a stable reference source? I measured rad numbers a while back and posted them. I will find the link and send it to you. Kevin
@Phredd , The mantles are all measured at the same distance, that is against the device. I don't have a known source to which I can "calibrate" the unit. So all values must be read as relative against each other. Your link doesn't work ;-(
Something strange in the link that shouldn't be there. @Phredd is this the link you intended to share Any radiation and light experts? - The Coleman Collectors Forum
Thanks, link works, in that I see the text. I have no permission to see pictures so dead end for me. If somebody can get hold of a copy of this "military lantern mantle tests" document I would be glad to get a copy.
Here is the text of my post on the CCF. It was part of a discussion of how to tell if your mantles were thorium or not. FROM CCF POST So - What real data do I have so far? Rad readings from 35 mantles of various types (Table 1). Experimental details: 1. Measurements were conducted with an Eberline RM14 radiation meter on the CPM (counts per minute) slow average setting. The detector held in position by a lab stand approximately 3/4" from mantles. Mantles were placed under the detector, and after one minute to allow stabilization, CPM were recorded as the range over the following 60 second. 2. The background range with no mantles was 70-95 CPM 3. Any mantle type with multiple rows were from different packages. One exception is the MilSpec mantles from Ludlow Corp. These are three measurements from three mantles from the eight that were in the same package. 4. Since mantle size varies these measurements should really be adjusted by weight, but I don’t have a balance that measures in milligrams. Notes: 1. CPMs do not measure thorium concentration. However, CPM should be proportional to thorium concentrations. So a mantle with a higher CPM count will have higher thorium concentrations (assuming no radionuclides are present). 2. I can not date any of the mantles, other than those in old wax paper are the oldest, Silk Lites are older than GoldTops. 2. The range of CPM for the 'hot' mantles was very wide - from 600-2800. Old Coleman Silk Lites ranged from 1400-2100, while Peerless ranged from 600-1100 (I only have a small sample size). The highest counts were from MilSpec mantles made by the Ludlow corportation. I note that this CPM range is smaller than actual thorium content that have been measured since the 1980s. Table 2 below is from Poljanc et al. (Sci Total Environ 374:36-72, 2007, Redirecting) where actual thorium content was measured and it ranged from 0.11 - 173 mg/g (milligrams thorium per gram of mantle). Hassan et al (Applied Science, Appl. Sci. 11, 1311, 2021. The Radioactivity of Thorium Incandescent Gas Lantern Mantles) shows an even wider range. However, Furuta et al (J. Radiol. Prot. 20:423–431, 2000) found a range similar to Poljanc et al.. Taken together this shows that there can be over 1000 times as much thorium in some mantles compared to others. 3. Based on a small sample size, there was no relationship between the use of the term "Made for European & American Markets", or and thorium presence. There were two Peerless packages that had this statement - both made in India - one had 600-700 CPM and the other was at background. Again, very small sample size. A similar finding was presented in the paper by Poljanc et al where they sampled some mantles purchased in Austria (country of manufacture unknown), that were labeled 'non radioactive in 6 languages. These mantles had thorium content that ranged from 102 to 150 mg/g. (see table 2). My Tentative Conclusions (subject to change based on corrections and new data) 1) The range of thorium in mantles can be large 2) You cannot determine whether the mantles have thorium unless you use a radiation meter.
In Germany all trash which is collected or brought in at disposal stations is tested for radiation. The agency that is involved for radiation publishes montly finds. Mantles with thorium, found in a truckload !: "Zum weißen Leuchten geschaffen, als grauer Müll gefunden – Glühstrümpfe mit Thorium, 75 kBq." Made for white light, found as trash, mantles with Thorium 75Bkq Or: "Nie geleuchtet und dennoch gestrahlt. Gasglühstrümpfe, ein mit Thoriumnitrat imprägniertes Baumwoll- oder Kunstseidegewebe, das in gasbetriebenen Lampen zur Erhöhung der Lichtausbeute eingesetzt wurde und teilweise auch heute noch eingesetzt wird." Never lighted but nevertheless radiant. Gas mantles with Thoriumnitrate impragnated of cotton or seide for gaslights, etc. They find all kind of curious stuff in dumpload of carbage !
Well the law in Germany on radiation is very straight. I am not an expert but stories go that people are visited by radiation contamination groups/people/firemen for having Radium drinking mugs on ebay. If you look around on that news page you see that they even find 5 (five !) hand watch arms with radium in a dump truck full of garbage at a waste burning facility. So the detection loops are darn good. If you then considering me, riding to and from lamp meetings with a dump load of mantles in the back..... A link to a german article about thse mugs.
