Reply With QuoteHow old is the watch? Most things 1950s onwards would be Tritium I would expect ( bit of a guesstimate)
I am trying to tell if my watch has Radium or Tritium lume. What signs are there other than a Geiger counter? I have found through research that you can use a UV light but unsure of what I should be looking for.
Cheers
How old is the watch? Most things 1950s onwards would be Tritium I would expect ( bit of a guesstimate)
Cheers..
Jase
https://www.rolexforums.com/showthre...929#post441929
Based on this the date and the dial could help as well, if it's Rolex.
1960s dial but am unsure if Tritium or Radium.Originally Posted by JasonM
On the cusp then from what I've just read.
Cheers..
Jase
Both radium and tritium lume work by beta particles emitted by the radium or tritium causing a chemical compound in the paint to fluoresce. UV light will also cause the compound to fluoresce in both cases (just as it also causes more modern lume to fluoresce), so I would not have thought that UV would allow you to differentiate between radium and tritium.
I don't know how to differentiate between radium or tritium other than by level of emitted radioactivity or age/manufacturer/model of watch.
Thanks. Not going to be an easy task!
My 53/54 Blancpain is Raduim, so I would think a bit later.
Best way to find out is a Geiger Counter. The age of a watch is not a good guide simply because an old watch can be de-contaminated, but it's still an old watch.
Whoever does not know how to hit the nail on the head should be asked not to hit it at all.
Friedrich Nietzsche
Would it glow for a few seconds after turning of the UV light?
Guessing there are no markings anywhere on the watch? T or an R were used to denote.
I have watches with both.
For me the easiest way to tell is a UV light
The radium compound will not glow during or after exposure to UV.
Tritium dialled watches do glow after exposure. In most cases briefly but in the case of a 08 dated CWC it glows brightly for quite a while after.
That said I also have radium watches that still give off the very faintest glow when in total darkness and my eyes are dark adjusted.
Are you sure your Radium watch isn't a relume? Radium should defiantly glow under UV light
Nope all original ATP and A17 among others
None of my radium watches glow under UV
All my Tritium watches do briefly.
All of my known Radium watches glow (GSTP pocket watch and 1945 Tudor)
This article states that a Radium watch should defiantly glow
http://rolexpassionreport.com/15606/...olex-luminous/
I will take some pictures later today with a UV light on them.
Unfortunately my GSTP is away for a service with Duncan currently so can't check that.
Watch this space...
:-)
The theory is that the phosphor in radium lume compounds degrades and is burnt out hence doesn't glow any longer when exposed to uv but with tritium lume the phosphor remains active even when the radioactive compound is exhausted so will still glow temporarily when the phosphor is excited. There may of course be some variation in actual pieces.
I believe the change over was around 1960/1 give or take a year or two depending on the manufacturer.
Last edited by Padders; 8th June 2017 at 08:21.
In the link he is using UV to identify if the £10k bezel will glow and if it does then it is Radium.
I think you mean the degradation burns out the radiation that makes the Zinc Sulphide glow. When under UV light you are charging the zinc with the UV.
Radium is not emitting any light but alpha particles (among other things). Those particles will in turn excite phosphorus atoms and they will emit light through a phenomenon called radio luminescence.
In time Phosphorus will degrade under the bombardment of alpha particles. So it may shine under UV, or not, depending on the phosphorus left.
'Against stupidity, the gods themselves struggle in vain' - Schiller.
Would you not expect some trace rather than nothing?
I'm meeting my dad later who is a science man so hopefully he can help
Thanks
It depends on many things, including the age of the dial, the quantity and activity of the Radium used...
I would expect some trace but it could be quite faint.
'Against stupidity, the gods themselves struggle in vain' - Schiller.
Right the results are in.....
Firstly I must say I was wrong, Radium does glow under UV but the 'glow' is not visible with the naked eye (or my naked eyes at least) however if you put a camera lens in between the eye and the dial the glow is intensified. I have never seen this before so it came as a surprise.
For my little experiment I chose watches that were a similar size with similar sized lume plots to try to make it as fair as possible, the thinking behind this being the more lume the more glow.
The Radium dials are a late 30s / early 40s ATP and a A17 from 52
The Tritium dials are a Hamilton from 82 and an 06 CWC
I exposed all watches to natural light for 30 seconds and then placed them in shadow.
The radium watches did not glow
The Tritium did glow when placed in shadow
I then shone a small UV torch on the watches, again for 30 seconds.
Shock horror you can see the Radium lume glowing, as I said before this is not visible to the naked eye but you can see it when looking through a lens
I did the same with the Tritium and as expected they lit up like a Christmas tree
Having discovered that a lens makes lume more visible I tried with my manky Tudor sub.
Where the dial has degraded over the years so has the lume in some areas, this has caused the Tritium lume to disintegrate and this has spread over the dial in a star burst pattern. As you can see the hands and pearl glow brightly.
Lastly I am wearing my 08 CWC diver
This is what the dial looks like before being exposed to light
As you can see the hands and dial are different shades
10 seconds by a window and....
For clarity I used a cr@ppy UV torch from fleabay, shadow was provided by a copy of living Etc. And the camera used was my iPhone.
What have I learnt from this? I should really go to work...
I stand corrected.
John
See this link for:
"The first time I did a UV flash test on my known radium-dialed watches, I was shocked to discover that two of them had ZERO 'glow'.... but when I went to a completely darkened room, I was able to detect extremely faint and brief (<.05 sec) glow. Most of the other radium dials (~30) had brief (albeit <0.1 sec in many cases) fairly obvious glow. The Geiger readings on the weak glowing two were strong and the watches otherwise quite original-looking, so I believe these had the original radium paint."
Nope I mean exactly what I say, Radium and Tritium lume degrade in opposite ways. The radium half life is incredibly long (1600 years for Ra226) and it continues to emit big heavy alpha particles (and some beta and gamma) pretty much indefinitely on the timescale under discussion, long after the luminescent component is degraded (basically burnt out) whereas tritium (a beta emitter) has a half life of about 12 years so is all but inactive after 20 leaving the luminescent component still active but no longer receiving the constant excitement from the radioactive source hence it can usually be made to glow strongly but briefly under UV.
Last edited by Padders; 9th June 2017 at 08:58.
Well I think he is either plain wrong or being misled by relumed pieces. He has it arse about face, tritium lume will have stronger residual glow after excitement than radium lume all other things being roughly equal. That article has clearly been translated from another language and is long and rambling so perhaps some of the original clarity has been lost.
Last edited by Padders; 8th June 2017 at 11:20.
Yes, in the case of both radium and tritium -- but on any particular watch it depends on how much the fluorescent compound has degraded.
It should be noted that the fluorescent compound itself appears to decompose chemically over time (and I think higher radioactive flux could accelerate this process in radium watches). Therefore it follows that older watches will tend, on average, to glow less under UV and remain glowing for less time after the UV is removed than newer watches.
This could explain why some radium lume watches don't fluoresce at all under UV: The fluorescent compound has chemically degraded. But the same will happen to tritium lume watches eventually simply due to chemical decomposition.
However, neither lack of glow under UV nor presence of glow under UV can on their own indicate that a watch is radium or tritium. Emitted radioactivity is still the only reliable indicator.
I agree with this.
And some radium lume watches do glow (a bit) under UV simply because the fluorescent compound in the radium lume has been 'lucky' enough not to entirely decompose over time.
Last edited by markrlondon; 11th June 2017 at 00:14.
I have bought this iPhone Geiger counter and it works but someone on another forum has suggested that it's wrong. The watch has a reading of 20 microsoev, is this too high? My GSTP pocket watch was 47! They are saying their 1960's watch only measured 1.38 so mine must be wrong. I have looked at other examples of vintage watches and their readings were 5-37. Thanks
Have a search, it's all in another thread. If I can find it, I'll post a link.
In the meantime, ignore the microsieverts (they don't relate to the measurement you are trying to make) and simply use it as a yes / no detector for radiation.
Assuming this iPhone gizmo actually works and isn't just snake oil, then it may do the job since the alpha and gamma will penetrate the crystal from a radium lumed watch whereas the less penetrative beta from tritium likely won't, therefore if you get a meaningful result at all then the lume is likely Radium based. Don't forget to consider the background radiation and discount that.
Last edited by Padders; 9th June 2017 at 11:53.
You've more clearly said what I was trying to get at...thanks. My minor amendment is to imply that the units (microsieverts) are not meaningful, but getting additional counts on the detector is.
So what do the radium lume dials mean to your health then? Let's say you opened a radium watch, removed the hands and serviced the watch.
What is this going to actually do to you?
See http://forum.tz-uk.com/showthread.ph...ls-with-radium
In short, don't eat it, that would definitely be bad. Don't breathe the dust either. Wearing the watch is probably fine, though.
That depends upon several things...including chance. It won't be anything good, but it might be nothing.
I know that's not very satisfactory, but it happens to be true. I've posted about this before, so a search might find it, but Radium needs to be ingested (or inhaled) to do you harm. Ask yourself how that might happen.
Once inside your body its chemical nature is to find a route to your bones, where its emissions have a very short pathway to damage living tissue. Thereafter you're worried about a stochastic effect (link)...it may be nothing or it may cause your early death.
There's a lot more on the net if you feel the need to understand this.
What I mean is I've read previously about the 'radium girls' who were eating the stuff daily yet it was only a few of hem that died and the rest (that even got sick) they reckon could have been nothing to do with it anyway.
I know that's not very scientific but I just wonder if what I've read is true whether even snorting the contents of a scraped off dial would even do anything to you.
I guess we'd never really know but I suspect if it's that dangerous there would be a hell of a lot of stories of dead watchmakers floating around.
Please, read up about this. Radiation causes cancer, whether or not you get a cancer is down to chance. Whether or not the cancer kills you (in this day and age) is down, in some part at least, to luck. The greater your exposure / dose, the greater the chance. You take the risk...please don't expose others (your family etc) unnecessarily.
PS How did this post acquire a smilie with sunshades?
Edit: As for your last point, don't guess, just realise that Radium luminising is now prohibited, replaced and regulated to the eyeballs...because it's f#@+%*¢& dangerous!
Last edited by PickleB; 9th June 2017 at 21:26. Reason: I worked out the answer to my question
I'm a little confused about lume now, having never really thought about it till now.
From this thread, I understand (I think) that "old" watches used radium and then later tritium to cause a chemical reaction which caused the markers to glow 24/7 without needing to be "charged" by UV light - is this right? I assume this glow would be very faint and would need dark adjusted eyes, and as the fluorescent material degraded, the luminescence would fade, irrespective of the half life of the radium (hundreds of Years) or tritium (12 years). So, such a watch could be put in a dark box and would glow even a year after being in the complete dark. Am I about right so far?
So, modern lume, or "superluminova" - how does that work? My watches (new Rolex / Omega) glow very intensely when charged by sunlight or a torch, but very rapidly fade such that after 15 minutes they are barely noticeable without dark adjusted eyes. I got up at about 4 am recently and noticed my Speedmaster glowing in the dark - some 6-7 hours after "lights out", albeit faintly again. Does a modern watch glow 24/7 like the radium/tritium ones (I assumed not) or do they exclusively require UV light charging?
^^^^^^
And LUMINOSITY IN WATCHES.
What I found interesting about one of the articles I read was the guy went on about how potentially dangerous it is and how he wears a mask, does it on paper towels then chucks it in the bin!
How is that responsible?
So if it's that bad why risk doing that to someone else? So the dustman comes along, opens the lid of the wheelie bin and a swirl of air helps him breathe in a load of radium dust! Unlikely maybe but isn't that the very same 'unlikely' theory he goes on about.
Very good question.
BUT...why ask me / us? He's the one to ask, if you want a reasonable answer.
Edit: However, not wishing to be unhelpful, here's a hint: link.
Last edited by PickleB; 9th June 2017 at 22:39.
No, none of the lume in question works by chemical reaction. If it did there wouldn't be any lume left in a mattter of minutes or hours. Read back through the thread and you will see that radium and tritium lume work by using radioactive decay to permanently excite an additional phosphorescent material. This effect lasts for decades until degradation stops it being effective, in the case of tritium some short lived glow may remain, less so in my experience with Radium due to their respective failure modes. Superluminova is rather different in that there is no harmful radiation emitted, it works by a quantum energy absorbtion and slow re emission effect. Doped Strontium-aluminate is a common form. S-L is not self charging like the other 2, no exposure to light means no glow.
Last edited by Padders; 10th June 2017 at 08:37.
Yes, I appreciate this. 'Chemical reaction' seemed a simpler way of describing what we all understand, to a group of Watch enthusiasts (not physicists!) rather than typing a paragraph like yours. Perhaps I should have been more semantically correct. I do have a great interest in physics and am currently reading a textbook on radioactivity, though some of it does go un-understood!
Anyway, I appreciate your reply :)
I think he was underlining the important distinction between a chemical and a nuclear reaction (don't try the latter at home). But in fact, fluorescence is an electromagnetic phenomenon; electrons are excited to a higher energy state, then drop down to a lower one releasing photons which we see as light. It's not a 'chemical reaction', in the technical sense, but it involves orbital electrons, not nuclear particles, so it's chemical, rather than nuclear.
The difference is in how the electrons get their extra energy in the first place. With radium or tritium paint it's because they get hit by other electrons (beta radiation) emitted from the radioactive nuclei. With SuperLuminova, or any phosphorescent paint, the input energy comes from light, usually sunlight.
I understand that cheap(ish) geiger counters can be sourced from Ebay however I recall that they need to be constantly calibrated otherwise they don't really tell you very much. Of course, if you fly regularly, you can probably ask the nice people at Border Force if you can borrow theirs (don't ask me how I know this).
I don't think calibration matters too much for this: according to this video, the noise alone will make it very obvious if there's radium in there!
https://youtu.be/ayghIDng8X8
I was heartened slightly by the difference in readings between the face and the caseback but I think I'd still want some reassurance that the counter is accurate - especially if there was any suggestion that it might be under-reporting rather than over-reporting.
For a detector to give you anything like meaningful readings of dose (sievert - Sv) you would need something other than a Geiger counter and it would be quite expensive. You're better off listening to the clicks or registering the counts per second as a qualitative assessment
I think I've posted about this before, but the radiation from watches that will be of most concern will not be giving a dose to your whole body (as is the case with penetrating gamma radiation) and that's what the run of the mill Geiger counters are set up to register.
You'll be much more concerned about the localised dose to your skin, and that's quite difficult to assess quantitatively without a lot of knowledge and effort.
Edit: Some of my previous posts:
And in that thread #19...that points to #32 in another thread. Then there is another thread with a discussion of intruments at and around #18.
Last edited by PickleB; 10th June 2017 at 19:22.
It stands to reason that the radiation received passing through the caseback (and into the wearer's wrist) will be much less, at least an order of magnitude less I should think, than that registered through the crystal because of the absorption and shielding of multiple layers of metal in the movement and case. I have no problem wearing a watch with radium lume, that said I handled alpha and beta sources pretty often back in the day when I was studying such things so am perhaps less leery of radiation in general than some. As noted above, where I would be careful though is in the ingesting or inhaling of any alpha emitter. Touching an alpha source isn't all that dangerous as only gamma (and to a lesser extent Beta) can really penetrate the skin deeply but it is advisable to wash your hands afterwards and take precautions if dust is involved.
Last edited by Padders; 10th June 2017 at 19:08.
Thank you for bringing back a sense of proportion in this thread. I was in 2 minds about doing it because I might not have been as diplomatic as you were.
'Against stupidity, the gods themselves struggle in vain' - Schiller.
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