Un tritium qui lumine encore?

Pour moi, mais je peux me tromper, du tritium qui fonctionne après 44ans, qui fonctionne 15sec et s’estompe ça s’appelle du luminova…

J’avais cru comprendre que le tritium fonctionnait « tout le temps » quand il était actif, de jour comme… de nuit…

Si je me fourvoie, merci de me dire…

Bonjour.
Sur ma r—– SD de 1997 les index tritium réagissent a une lumière vive,mais s’estompent assez vite.
La nuit après un temps d’adaptation des yeux le tritium éclaire encore mais moins que du luminova bien sur.
Celle ci étant une des dernières séries tritium je m’était posé des questions sur le pourquoi il réagissait a la lumière.
Mais il parait que exposer a une forte luminosité c’est normal,mais très cours dans le temps.

Le tritium reste actif après 45 ans, puisque sa demi-vie est de 12.32 ans, ce qui signifie qu’une montre de 25 ans contient du tritium qui est à 1/4 de son activité initiale et a 37 ans, environ 1/8. Maintenant le tritium ne fait pas tout. Il doit etre utilisé en conjonction avec un élément excitable (le phosphore pour les montres) pour que la lumière soit émise. Or ce phosphore est aussi soumis à vieillissement et c’est peut-etre cet élément qui peut expliquer la forte variabilité de luminescence que j’ai constaté entre 2 speed pro du début des années 90. Une des deux ne crachait quasi plus rien. Je ne connais pas ces facteurs de déterioration (UV?).

Il peut également y avoir un détachement de matière qui contribue à la diminution. Du coup, faites quand meme aztention si vous bricolez l’intérieur de vos montres. Si le contact n’est pas trop grave (faible pouvoir de pénétration), lavez-vous les mains après, surtout di c l’heure de passer a table, l’ingestion pouvant être plus problematique

Evil_OOb a écrit:

Et pour les trèèèèèèèèès vieilles Radiomir… on n’les touches pas alors?

Sans tomber dans la paranoia, pour le radium c’est mieux de laisser faire un pro à mon avis

What Are the Risks of Radium Dials?
I have never gotten an explanation of exactly how risky these radium watch dials are from someone who I would judge to really know what they are talking about. Many people have a little knowledge and make claims that range from « immediately call your hazardous waste disposal people », to « hey, watchmakers have been cleaning these watches for decades, and there isn’t any signs that this is any more dangerous than crossing a street. »

The primary health risk of Radium is that it is radioactive and if it is ingested or if dust particles containing radium are inhaled, it can lead to various bone diseases and forms of cancer. While there is no safe level or radiation exposure, everyone is exposed to a certain amount of radiation every day. The question is: « are the levels of radiation from the radium dials high enough to worry about? »

Not all the radioactive material remains where the paint is visible. Over time, this paint will become very dusty and it is important not to breath any of this dust. The watch crystal should not be removed without a good reason, nor should the watch case be opened up. The dust is due not only to the normal aging of the paint, but also because when radium breaks down, the force of emitting the alpha particle during the radioactive decay causes the daughter atom to recoil. This recoil is strong enough to break the chemical bonds that holds the atoms in place. The resulting daughter atoms will move a little ways away and then settle. These daughter elements, such as radon-222, polonium-218, lead-214, and such, are all radioactive and just as much a problem as the radium.

In the 1920s, radium dials became popular enough that many companies started producing them. They would hire girls and young women to paint the dials and they were encouraged to lick the tips of the paint brushes to get a sharp point. The whole environment in some of these factories was very lax about the radium. The women would sometimes do things like paint their teeth, faces and nails with this stuff to surprise their boyfriends. Many of these women would later develop health problems and some even died due to ingesting radium.

If you do a web search on the Radium Girls, you will find lots of stories on them. Many of these stories are nearly identical, but one of the better articles is by Bill Kovarik.

Now, this might sound very frightening, but these women ingested a LOT of this paint, « only » a few died, and probably not more than 20%-40% had health problems. It is not clear how many of these health problems were due to the radiation or due to the heavy metal poisoning. There are lots of risky activities in this world, from crossing the road to eating fatty meat, that most people don’t think twice about doing. However, people seem to panic as soon as you mention radiation or « mad cows disease ».

On the other hand, ingesting this radium may be significantly less of a problem than breathing it. Ingested radium will either pass through your system, or act chemically like calcium and enter your very slow growing bones. The CDC’s Radium webpage says that 80% of ingested radium will pass directly through you and some of the rest will eventually be filtered out by your kidneys. Radium dust in your lungs, on the other hand can stay there and potentially cause lung cancer.

One particular concern of radium decay is the daughter element radon-222. Radon is a noble element so it won’t chemically rebind and it is also a gas so it will float away from the dial. Radon has a half life of about 4 days, which is probably enough for it to diffuse to anywhere in the watch case but probably not long enough to escape before it decays. The daughter elements of radon-222 are radioactive solids, which will settle on the watch parts. So, it seems likely that a watch with a radium dial will cause the entire movement and inside of the case to be covered with a very find dust made of radioactive material. Again, I am not an expert here, so this may or may not be a real problem, I don’t know. I’ve, however, read discussions about how entire boxes and cabnets have become radioactive due to storing small amounts of radium in on spot.

Now it is true that as time goes on, the break down of the radium will cause it to lose some of its potency. Unfortunately, the half-life of radium-226 is about 1600 years, so these watches will be about as radioactive 200 years from now as they are today. For all practical purposes, these watches will be radioactive forever.

One final comment on the possible health risks of radium is that the dial painting companies weren’t exacting in their formulas. It wasn’t just radium-226 that was used, but a variety of different radioactive elements. Most of these other elements will decay faster than radium-226, so they may be less dangerous now. Also, depending on how the paint was mixed up, some dials were very hot, while others were not. If you are concerned about a particular watch, you should have it measured. Anything else is just a guess.

Radioactivity, it’s in the air for you and me !

Omegaman a écrit:

Radioactivity, it’s in the air for you and me !

ca me rajeunit pas ca !!