Tritium backlighting in a Swiss military watch. Tritium keychains and radiation from them Tritium went out in the clock what to do
Popular tritium keychains cause a lot of controversy: some are delighted with bright, compact and "eternally" luminous products, while others talk about their radioactivity and health hazards. Manufacturers, on the other hand, are confident in the safety of their products and offer tritium markers as alternative light sources that do not lose their brightness for 25 years. Whom to believe? Let's try to figure it out.
What is tritium?
Natural tritium (T or H-3) is a superheavy radioisotope of hydrogen with a half-life of 12.5 years. It is constantly formed in the atmosphere during the interaction of neutrons from secondary cosmic irradiation with nuclei of oxygen, nitrogen or argon. The isotope quickly transforms into molecules of ordinary water contained in the air, and then falls to the ground in the form of rains. The biosphere contains extremely little of it - no more than 2 kg, and most (90%) of the radionuclide is concentrated in water.
Technogenic tritium is produced by irradiating lithium-6 or uranium and plutonium isotopes with neurons in nuclear reactors. This technology is laborious and expensive - the synthesis of 1 kg of tritium costs $ 30 million. It can also be isolated and concentrated during the purification of heavy water used as a moderator in nuclear reactors.
The secret of the glow of tritium key rings
The luminescence of the key fob is provided by illumination based on gaseous tritium, which in terms of its brightness surpasses other light compositions of constant action. The main component of the light element is a transparent sealed tube made of carbonate glass, internally coated with a luminescent compound and filled with gaseous tritium. The radionuclide emits beta electrons, which bombard the phosphor and cause a bright glow. The keychain is capable of uniformly glowing for 12 years without recharging, since the half-life of tritium is 12.5 years, and the time for the complete decomposition of this radioactive isotope is 25 years. That is, even after the guaranteed period, the trinkets will glow, then the intensity of the light emission of tritium drops, but by no more than 40%.
Tritium gas toxicity
Tritium gas is an important biological radioisotope that emits weak beta radiation. Due to the short path length - no more than 5.8 mm, beta tritium particles are destroyed in the air or are completely retained by human skin. To a greater extent, the isotope is dangerous if it enters the body during breathing or eating or eating. Low energy electrons emitted by it create increased ionization around them, causing damage to biological tissues and organs. Bremsstrahlung X-ray radiation, which occurs when the electrons emitted by tritium are decelerated in the electrostatic field of the phosphor, also has a negative effect. And although it is weakened by glass, it still gives radiation up to 10 μR / h at a distance of one centimeter.
First tritium-based light elements
The first company to use tritium gas as a base for luminescent paint in 1918 was Mb-microtec AG (Switzerland). Unfortunately, the resulting tritium paint quickly decomposed and reacted with water, forming highly radioactive tritium water. After a long search, the company created the GTLS technology and began producing tritium gas light sources under the Trigalight brand. Trigalight is a borosilicate tube with a diameter of 12 mm and a length of 1.5 meters. In the process of making sources, it is drawn on a special machine developed and patented by the company's specialists. The result is up to 120 half-meter glass cones with a width of 0.5 mm.
Each of them is covered with reflective paint from the inside and filled with tritium gas. Since the brightness of the glow and the service life of the finished trigalight depend on its quantity, as much gas as possible is pumped into the tank. At the final stage, the long tubes filled with tritium are cut into pieces by the laser, and the ends are instantly sealed. After cutting, the finished trigger lights are checked for tightness by the operator in a dark room.
Mb-microtec AG annually produces up to 10 million trigalights of different sizes and colors, which are used to illuminate not only key fobs, but also information plates, nautical compasses, portable flashlights, dials and hands of wrist watches. Tritium illumination, placed on the scope of hand-held firearms, solved the problem with aiming accuracy that arises when conducting night shooting. Bright trigalights are successfully used by leading manufacturers of military weapons: Kalashnikov, Kriss, Glock, Beretta.
In addition to Mb-microtec AG, similar light sources are produced by the Canadian company SRBT, and they are used to illuminate the corridors of commercial and military aircraft.
Alternative tritium light compositions
There are other tritium based continuous light sources. In such light compositions, the formulas of which are kept secret by manufacturers, it is in the form of tritiated resins, fatty acids or surfactants associated with the phosphor. However, self-luminous tritium dyes are not used in tritium key chains, since they are significantly inferior in glow brightness to trigalight and are more dangerous in terms of radiation.
Trigalight is a safe luminescent alternative
Trigalight light sources are fixed in the products in such a way that, subject to thermal and mechanical conditions operation, capsule breakage and tritium gas leakage becomes unlikely. Numerous studies have confirmed the safety of these light sources due to the small capsule size and durable carbonate glass, as well as their compliance with the international standard. ISO quality 9001.
Unfortunately, the market today is flooded with cheap tritium keychains made in China. They use glass capsules, similar to trigalights, but giving an excess of the radiation background by several times. Experts suggest that Chinese factories are using another, cheaper gaseous isotope instead of tritium, which emits stronger beta radiation and negatively affects human health.
Tritium Keychain: Dangerous or Not?
Tritium is always present in the human body, coming together with food, air and through the skin. Being in a gaseous state, it does not pose a great danger, since the beta particles formed during the decay of tritium have a weak penetrating effect and are quickly absorbed by an air layer 5 mm thick. If it enters the lungs, then very quickly, literally in three minutes, it is excreted from the body. Much more dangerous for the body is an aqueous solution of tritium.
I have a CARNIVAL 8638G in silver with tritium green cones. I really like the watch - excellent workmanship. classic calm design, comfortable size. And most importantly: the backlight works always and everywhere, the time is visible around the clock.
Now I decided to take the second such watch "in reserve", but with a black case and bracelet and blue backlighting. The design has changed somewhat. In the review, you will see a detailed description of the new watch, as well as a comparison with the old ones.
I bought my first watch at Gearbest. Then they came to me in an ordinary watch box. If you are interested in the details, please google my review “Excellent wristwatch CARNIVAL 8638G with tritium”.
This time the watch arrived in a large representative box. Dimensions 203 x 153 x 85 mm.
Inside lay:
Gift bag.
A simple device for shortening the bracelet.
Plastic warranty card and user manual.
Manual in Chinese and English.
Of course, the watch box itself was inside.
The situation with its quality has not changed over the years.
Shabby dust jacket.
The box itself is made of bumpy cardboard with shabby leatherette. As a result, as a gift, this packaging is not very good.
The watch itself is put on a leatherette cushion with a corporate logo.
On the inside of the box there is a soft leatherette insert so that the watch does not get damaged on the way.
The watch itself was completely covered with films. A branded tag hung on the bracelet.
To better demonstrate the watch, I photographed it in different lighting conditions, at home and outdoors.
The dimensions of the watch case are as follows: diameter 40 mm, width with the crown 43.6 mm, height with lugs 49 mm.
The glass has a good anti-reflective coating. Therefore, at some angles the glass is invisible, and at some there are only small reflections in it.
Let's get started with the watch face. Its appearance is quite classic and resembles a military watch from the Seiko 5 series.
The manufacturer also has light dials, but I perceive the white hands on a black background as more contrasting, and I often choose this option.
The dial has two windows, the so-called apertures, through which the day of the week and the current day of the month are shown. This is done using the calendar discs that are part of the mechanism. Aesthetes may not like the fact that the discs are at different levels. The disc with the days of the week is located slightly higher.
The hour markers on the dial are flat and are simply painted.
Tritium flasks are glued in next to all hour markers. At the 12 o'clock position it is orange, the rest are blue.
The dial bears the T25 mark, indicating the amount of tritium.
More details http://forum.watch.ru/archive/index.php/t-130262.html
All arrows also have blue tritium flasks glued in.
For those who are interested in the details, I made a few more macro photos.
To show the case from all sides, it is more convenient for me to separate the links of the bracelet. Therefore, I will digress and demonstrate another bracelet.
The clasp is the so-called hidden automatic "butterfly" clip.
The bracelet has a small margin on the length, just fits my wrist with a circumference of 20 cm.
The finishing of the watch case combines areas with satin and polish.
Not so long ago, I learned that the polished corners of the lugs are an interesting feature in the appearance of the watch.
The coating on the case resembles IP (Ion plating), but it's hard to say for sure. More details https://www.alltime.ru/blog/?page=post&blog=watchblog&post_id=606
The thickness of the watch is 12 mm.
The glass is flat, protrudes slightly above the body. Sapphire is promised on the store page, but home tests do not confirm this.
The crown with a glossy finish is adorned with the company logo, strongly reminiscent of the Omega symbols.
The crown diameter is 6.2 mm.
The back cover is screwed down. Moreover, it is twisted so tightly that I could not open it with a special key. Therefore, we will not be able to look at the mechanism. If someone is very interested, then I can take the watch to a watchmaker to open the lid.
Let's now get to know the bracelet.
Stainless steel bracelet with cast links.
Butterfly clasp.
The links of the bracelet are matt, finished with a longitudinal satin finish.
There are small polished inserts with a glossy finish.
The metal on the links is not completely hidden under the coating, the side surfaces are "bare".
The back of the links is completely matte.
Place of docking with the body.
The bracelet feels like a sturdy budget midrange typical of a $ 50 Chinese watch, or a $ 100 Japanese watch. That is to find fault with appearance difficult, but the links sometimes move taut, and do not "flow" freely, as in the bracelets of expensive watches.
Let's just show you how the watch looks on the hand.
The girth of the wrist is 20 cm. The size of the case fits well, a little smaller and would look small.
The readability is excellent.
Side view. For a larger hand, the bracelet will be too small.
The watch is not very thick, it does not get in the way under the sleeves.
I've been wearing my watch for a month. The clasp never failed.
The clock weighs 129.5 g. Personally, they do not seem heavy to me.
Let's see what accuracy the watch showed during this month.
I put the exact time on the site.
We check in a month.
We went ahead for 8 seconds. A decent result for a budget quartz movement.
By the way, the clock is ticking very quietly. At night I put it next to the pillow, they do not interfere at all.
Now I would like to compare with my silver Carnival.
Surprisingly, the model number is the same, but the watches are different.
The main difference is that the silver watch does not have a day of the week window.
They have a Swiss mechanism from Ronda.
At black hours, the days of the week can be selected in either English or Chinese. I doubt Swiss movements have a second option.
The rest of the differences are purely cosmetic. The black watch does not have an Omega badge on the dial, but it does have the T25 lettering. The back covers are also designed differently, I did not take a comparative photo.
Let's now look at tritium backlighting from a comparative perspective. Let me remind you that for black watches it is blue, for silvery ones it is green.
Tritium bulbs do not glow very brightly, but this brightness is constant, does not fade without external lighting. As a result, the time readings are clearly visible all night. It is generally believed that green cones are the brightest compared to other colors, but in this case, the difference in brightness is negligible.
Let's let down the outcome.
This is one of the most affordable tritium-illuminated watches.
But otherwise, they don't disappoint. Stainless steel case and cast bracelet, quiet and precise quartz movement. This already attracts the price range of $ 50-60.
I am very pleased with my Carnival watch.
That's all.
The watch currently costs $ 76.82
And finally, a few photos taken outside the city.
The myth that radioactive substances glow is about to celebrate its centenary and, despite this, is still actively exploited by writers, artists and filmmakers of the 21st century. It goes back to the 20s and 30s of the last century, when paint based on zinc sulfide and copper with the addition of radium began to be actively used in household appliances. Zinc sulphide with copper is a common phosphor that, under the action of an electron beam, colors radar and oscilloscope screens in a "proprietary" green color, and as part of the paint glows under the influence of alpha radiation from the radioactive metal radium.
Mb-microtec has three divisions. In addition to the production of tritium light sources Trigalight and the "home" watch brand Traser, it also includes Glencatec. In fact, it is a research laboratory aimed at finding new applications for the know-how of mb-microtec. Her most interesting projects are related to the development of medical micro-robots enclosed in sealed glass capsules using Trigalight laser encapsulation technology.
In those years, radium was more popular than Marlene Dietrich. In mesmerizing promotional posters, happy families gathered around fireplaces that exude a mysterious greenish glow, and millions of people eagerly awaited the appearance of atomic ovens in their kitchens and atomic cars in garages.
After humanity was confronted with the dangers of radiation, euphoria was replaced by another extreme: the slightest mention of radiation makes people furrow their brows tensely. Meanwhile, even an ordinary banana can cause a false alarm from a radiation detector - after all, bananas naturally contain the isotope potassium-40. The smoke detectors we can see on the ceiling in every office use decaying americium-241.
The raw material for most sources is the so-called borosilicate glass base tube. Its diameter is 12 mm, length is 1.5 m. To obtain the micropipes of the required parameters, the base tube is heated and stretched on a special machine developed by mb-microtec. In this case, both the diameter of the tube and the thickness of the walls decrease, and the length, respectively, increases. From one base tube, 120 half-meter segments with a diameter of 0.5 mm can be obtained. This extremely delicate process is manually controlled: the operator controls the tube speed, heating temperature and air cooling rate. For the manufacture of rectangular "trigalites" a base tube of rectangular cross-section is used.
We visited the mb-microtec factory (Bern, Switzerland), where light sources based on radioactive tritium gas are produced. This production is unique in some way. Several companies in the world (they can be counted on one hand) produce tritium sources, but only mb-microtec technologies allow the manufacture of miniature flasks, suitable, in particular, for installation in a watch dial. Therefore, all watch houses that want to illuminate their models with tritium have to contact mb-microtec.
The process of applying a phosphor to the inner surface of a tube is one of the most important know-how of the company. First, the glass is cleaned and "activated". This process involves water, soap solution, solutions with basic and acidic properties. After drying, powdered phosphor is poured into the tubes. From the outside, it seems that the powder just flies through the tube and spills out onto the table from the other side, but thanks to activation, it covers the glass surface in an even layer. The filling process is repeated three times, after which the tube is sent for inspection. Each piece must exhibit an even glow in UV light. The finished tubes are sent to the oven for drying for a day.
Here is such a fish!
"Huge containers of tritium are being delivered to us!" - proudly announces John Williams, Technical Director mb-microtec. We expect that the next moment John will spread his arms out to the sides with the traditional gesture of "this is such a fish!", But his palms are drawing only medium-sized roach in the air.
The fact is that tritium is one of the rarest substances on the planet. Its world reserves are estimated at about 30 kg, while one kilogram costs about $ 30 million. Industrial tritium is produced in nuclear reactors, irradiating with neutrons with lithium-6. But the sun is full of tritium. Recall that tritium is an isotope of hydrogen, the nucleus of which contains one proton and two neutrons. In the conditions of the most powerful gravity and the highest temperature of the luminary (15 million degrees), the tritium nuclei collide with the nuclei of deuterium ("heavy hydrogen"), consisting of one proton and one neutron. In this case, the nucleus of a new chemical element helium (two protons and two neutrons) is formed, a neutron and a huge amount of energy are released. The helium nucleus is lighter than the nuclei of deuterium and tritium. If we recall the famous E = mc 2, where c is the speed of light, it becomes clear why the sun gives us so much heat.
For many years, physicists have been trying to recreate the processes occurring in the solar hell on Earth (and are making some progress). When they succeed, tritium will supply people with practically free electricity. Until then, it can serve us by setting fire to the phosphor in the glowing tubes. After all, the main property of tritium is safety.
Yes, it is radioactive, but the radiation of the radiation is different. The most dangerous gamma radiation (high energy photons) causes radiation sickness and cancer, although it is also used to treat cancer. Such radiation can only be blocked with a thick layer of material with heavy nuclei (lead, depleted uranium).
The specialist solders one end of each tube with a blowtorch, and not the tubes, but the cones are sent to the filling station and connected to the fittings. 30 fittings are located on a common manifold. First, air is evacuated from the tubes and the pressure in the system is monitored for some time. So the tubes are checked for tightness. After completion of the test, tritium is fed into the manifold. The brightness of the glow and the service life of the sources directly depend on the amount of tritium injected into them. In order to accommodate more radioactive gas, they are cooled by immersion in liquid nitrogen. Recall that the temperature of liquid nitrogen is -196 ° C. Upon completion of the refueling, the specialist solders the upper ends of the tubes with a blowtorch and carefully separates them from the station.
Alpha particles are nothing more than helium nuclei. Even a thin layer of material can be easily protected from alpha radiation, but it poses a danger if it enters the body. Notable examples of both are americium-241 from smoke detectors and the infamous polonium.
Tritium is characterized by soft beta radiation, which is a stream of electrons and positrons. You can even fence yourself off with a sheet of paper. The energy of the beta particle is not enough to penetrate the body through the skin. Needless to say, tritium radiation cannot leave the glass flask in any way. Even if you inhale a small amount of tritium, it will leave the body without having time to cause significant harm to it.
Laser cutting is perhaps the main know-how of mb-microtec. Long tubes, already filled with tritium, are placed in a machine that cuts them into the desired lengths with pinpoint precision. In this case, the laser not only cuts the workpiece, but also instantly solders the ends of the resulting segments, leaving no chance for tritium to leave the tubes. For safety reasons, the machine is sealed and locked during operation. It cannot be opened until the built-in sensor detects the complete absence of tritium inside the transparent case. With the help of a video camera and a monitor, the operator continuously monitors the quality of the cut. Immediately after cutting, the newly-made "trigalites" undergo another leak test: the operator examines a batch of sources in a dark room, looking for dark spots.
Nevertheless, when entering a gas station, we put on robes and special shoe covers, and on the walls in every room we observe highly sensitive gas analyzers and radiation detectors. They are able to sense the slightest leak of tritium and in the blink of an eye seal the room by activating an emergency ventilation system.
“The first reason for the increased safety measures is the official regulations,” explains John Williams, “the second is the low likelihood of tritium water being formed by accidental gas-liquid contact.” Tritium water, in which some of the hydrogen atoms are replaced by tritium atoms, is dangerous because, when it enters the body, it can stay there a little longer than the gas that we constantly breathe in and out.
The process of packing "trigalites" is fascinating: with quick and precise movements, a mechanical manipulator takes out microtubules measuring only 0.5 x 5 mm each from a handful, carries them over the camera with a flash and neatly places them in plastic pallets. Depending on the pallet model, each of them can contain 605, 943 or 1375 sources. Pallets are more than just convenient packaging. They are used in the assembly production of watches, where the same manipulator picks up microtubules and sets them on the dials - in a strictly defined place at a strictly defined angle. The gripping mechanism of the manipulator is pneumatic. During photography, each individual source is assigned a number. The photograph can serve as a confirmation that the source was made with high quality and exactly corresponded to the specified dimensions.
Finally, there is a third reason: after all, the aforementioned container is really big. Judge for yourself by an example: Traser Red Combat watches accommodate sources with an aggregate activity of 1 gigabecquerel (one becquerel means that there is one radioactive decay per second in the source). One container (the factory is allowed to store two) holds an amount of tritium with an activity of 50,000 curies, and one curie equals 37 gigabecquerels. So, if we count how many watches can be made using the entire supply of tritium in the factory, we get 3,700,000!
Verified by law
Of course, mb-microtec light sources are used not only in watches. They can be found in weapon sights, aircraft instruments, and fishing floats. The range of applications for tritium lighting is constantly expanding, with sources appearing in designer door handles, aircraft and mine exit signs.
This is not surprising: tritium sources provide stable light, last 25 years, and do not need power or recharging. This compares favorably with phosphorus-based phosphors and the like, which store light energy during the day, but after one hour spent in the dark, they lose up to 90% of brightness.
For those who were not convinced by the story about the safety of tritium, there was one last argument. Tritium backlighting is one of the most proven technologies in the world. Because there are few technologies that would attract such close attention from state regulatory bodies.
Competent educational program on illumination in hours
Friends, I present to your attention very competent thoughts in hearing about the backlight in a watch from a person named Strong. Since many questions are asked about different types of backlights, I think this article will be a good educational resource. Any questions related to the article, ask in the appropriate thread on the watch.ru forum. We also advise you to read about the types of backlighting in watches.
1. In 1902, for the first time, a light composition activated by radium compounds was applied to the dial of a watch. On the danger of radiation
then they did not take much steam, the main thing was that the clock and military instruments were visible in the dark. But this phosphor from alpha and beta radiation of radium degraded after a few years and ceased to glow, although the half-life of radium is 1600 years! But, nevertheless, clocks and devices were covered with such light compositions right up to the 50s, then they began to look for a replacement and found - tritium.
2. Light compositions with tritium activation are used to this day, although to a lesser extent than before, since there is GTLS-technology (tritium in tubes in the form of a gas, but more on that later). So, tritium, which is used in technology ALL is produced artificially, by irradiating lithium with neutrons in reactors. And on Earth, natural tritium will accumulate no more than 1 kg - it is active and quickly dissipates. Tritium is a hydrogen isotope with a half-life of 12.3 years. It emits beta, which is trapped by a sheet of paper, i.e. much less dangerous than radium and its compounds. I wondered how tritium is added to the light composition, after all, it's a gas! It turned out that in paraffin (candles are made of it), some of the hydrogen atoms are replaced with tritium atoms, and then they are added to the light composition, which is used to cover the dials and hands of the hours (The most famous Soviet watches are Vostok, Komandirskie and Amphibia watches, tritium was used there until the end of the 80s ).
3. GTLS-technology or Trigalight is a development of the Swiss company Mb-microtec, a revolution in the field of illumination (IMHO). These are borosilicate glass tubes into which tritium is pumped in the form of a gas. The inner walls of the tubes are covered with a phosphor that glows from the beta radiation of tritium. The approximate time until the complete extinction of the trigalight is 25 years (not bad!) The most famous and inexpensive watches with this technology are Traser, then Luminox, Nite, and, well, absolutely elite Ball (they have numbers laid out from trigalites different colors, in general, beautiful). Who cares, go to the website www.traser.ru there everything is in detail)
This concludes the review of permanent illuminators and pass on to the light-accumulative compositions.
1. Light composition based on zinc sulfide - the worst light storage light composition! The afterglow time is no more than one hour - this is a shame and it is used in hours that are sold in underground passages for 100 rubles (((
2. Light composition based on strontium aluminate - afterglow time up to 18 hours (very good!). Arrows and numbers covered with this light composition are visible all night long without straining the eyes. An example is SuperLuminova.
Now the conclusion (this is my opinion, I do not impose my point of view on anyone):
When a person buys a watch, he reads the instructions, which indicate the type of watch mechanism, degree of water resistance, case material, etc. But NEVER IN ANY INSTRUCTION have I come across information about the afterglow time of the light composition! Why? Is this an optional clock parameter? In my opinion, reading information in the dark is VERY important. But manufacturers DO NOT bother about this in ANY way and it’s not good (. I’m not happy with the non-paint that covers the dials and hands in Casio watches, it’s about 6 hours long). I solved the problem individually, I myself cover the dials with a good light composition and hands of my favorite watches I use the composition based on the Green GL phosphor (afterglow time is 12 hours) and the INTERCOAT fluorescent film (where it is impossible to accurately cover with the light composition in liquid form).
I am not interested in LED backlighting, EL-ILLUMINATOR as well as any auto-backlight, because the clock should be visible ALWAYS, without pressing any buttons or other actions, such as turning the hand with the clock towards you. It's not mine ...
* Casio does not use tritium.
Expect to continue with the series of educational blog posts (including an article on all the possible types of backlighting in a Casio watch).
Tritium - superheavy hydrogen, denoted by the symbols T and H3 - a radioactive isotope of hydrogen. The tritium nucleus consists of a proton and two neutrons, it is called a triton and is denoted by t.
In nature, tritium is formed in the upper layers of the atmosphere when cosmic radiation particles collide with the nuclei of atoms, for example, nitrogen. In the process of decay, tritium turns into 3He with the emission of an electron and an antineutrino (beta decay), the half-life is 12.32 years. The available decay energy is very low (18.59 keV), the average electron energy is 6.5 keV.
Tritium is used in biology and chemistry as a radioactive label, in experiments to study the properties of neutrinos, in thermonuclear weapons (also known as a hydrogen bomb) as a source of neutrons and at the same time as thermonuclear fuel, in geology for dating natural waters. Industrial tritium is produced by irradiating lithium-6 with neutrons in nuclear reactors.
Due to the low energy of decay of tritium, the emitted electrons are well retained even by the simplest obstacles such as clothing or rubber surgical gloves. However, this isotope poses a radiation hazard if inhaled, ingested with food, or absorbed through the skin. A single case of drinking tritium water does not lead to long-term accumulation of tritium in the body, since its half-life is from 7 to 14 days.
Use in watches
In terms of use in watches, radium was initially used (hence Radiomir). After it was found that using radium for these purposes is extremely harmful to health, the watch industry switched to tritium (and, in addition, to non-radioactive compounds such as SuperLumiNova). Due to the radioactivity of radium, for example, a batch of Panerai Radiomir was sent to the bottom of the ocean.
Tritium is much safer, but the company requires special permission and trained craftsmen to work with tritium.
In the late 90s, Superluminova began to actively displace tritium. This is due to less difficulties in production and environmental friendliness, although this composition is inferior in luminescence (duration) to tritium. True, tritium has an important drawback, in addition to minimal radioactivity. This is a limited period of work due to the half-life. Such a glow in hours will last a maximum of 12 years (12.34 years is the half-life of tritium). The term is counted from the moment of tritium production! After a few years, the glow intensity decreases.
The current technology of using tritium in watches is quite simple: a glass vessel is taken, its inner walls are covered with a luminous substance (a phosphor, for example Superluminova), then the vessel is filled with tritium gas and hermetically sealed. The electrons emitted by tritium bombard the layer with the luminous substance, which creates the glow effect.
The radiation of decaying tritium has a propagation area of 1 - 3 millimeters, which does not allow them to penetrate into the human body. Accordingly, the radiation does not pass through the walls of the vessel.
