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pdxleaf
··"I cut it TWICE and it's still short!"Disclaimer: I fell into a rabbit hole about tritium lume. I don’t have a scientific background so it wasn’t a very deep hole and it didn’t take much for me to fall in. Still, this info about lume might be interesting to some others.
When talking about lume, we generally refer to lume that is made of radium, tritium or luminova. While only radium and tritium are radioactive, it’s easy to think of radioactive material as the source of the glow or illumination. But it is actually phosphor material that emits a glow, not the radioactive material. The radioactive material excites the phosphor, which then emits light. What makes the lume paint self-illuminating is the radioactive material that continuously emits energy.
As long as the material remains radioactive, the phosphor will continue to emit light. While the self-illuminating glow will be not as bright over time, it is because the radioactive material may be losing energy to excite the phosphor. But the paint will also glow less over time if the phosphor material deteriorates. If you shine a light on the lume and it glows, then it might not be glowing as brightly because the radioactive material has depleted. But if you shine a light on the lume and it doesn't glow, the radioactive material might still be just as radioactive but the phosphor material may have been destroyed.
Tritium is actually a gas, an isotope of hydrogen. Self-luminous paint production binds the tritium gas into a plastic binder, which is then combined with phosphor material and paint.
[Edit, per DanS below: "The polymer binder has hydrogen atoms in its molecular structure, and some of the naturally occurring isotopic hydrogen atoms are replaced with tritium in the molecular structure of the binder itself...Generally this "tritiation" is done to the precursor monomers prior to polymerization."]
There are many decisions to be made regarding the type of phosphor material that is used, as that will have a greater impact on how effective will be the paint.
The type of phosper is chosen based on how efficiently it converts beta-energy to light and the size of the phosphor particles. The size of the particles is important because it impacts how much radioactive material can be in the same material as well as how close the phosphor can be to the radioactive material, which can have a limited efficient range or distance.
In addition to the particle size of different phosphor, a silicate phosphor is preferred to a sulfide phosphor as the silicate based is more resistant to the harmful impacts of moisture and high energy radiation.
The choice of phosphor will determine the color of the paint:
Blue paint from calcium magnesium silicate, activated by titanium.
Green paint from zinc orthosilicate activated by manganese
Yellow paint from zinc cadmium sulfide activated by silver
Red paint from zinc phosphate activated by manganese
The differences we see in the color of aged lume, as well as how much it shrinks or how often certain references have moldy lume would seem to be the result of the type of phosphor used in the paint mixture as well as the plastic and solvent composition, more so than the radioactive material used.
Advantages of tritium over radium.
1. Tritium has low penetrating power and is thus safer for humans. Tritium is blocked by common materials like plastic and glass. Tritium is too weak to penetrate the skin. It must be inhaled or ingested to enter the body. Even then, huge quantities are needed to be extremely dangerous. Also, if tritium as a gas does enter the body, most of it will combine with oxygen to form water, which will exit the body in the urine, through moisture in the breath or as perspiration. If tritium gas is inhaled, much of it is immediately exhaled.
2. Radium is dangerous because if ingested in the body it lodges in bones and then radiates from there to cause damage to soft tissues. Radium emits gamma radiation, which continually radiates.
3. Radium also emits alpha particles, which destroy the phosphorescent crystals faster. Radium loses one-half of its original brightness each year following the production of the paint mixture. Tritium emits beta radiation, which does not destroy the phosphor. The rate of loss of brightness matches the rate of radioactive decay, about 6% per year.
4. Tritium has a half-life of 12 years whereas radium has a half-life of 1600 years. After 10 half-life periods, the material is considered not radioactive. This means tritium is radioactive for 120 years compared to radium, which lasts 16,000 years.
5. Tritium is a relatively lower cost to acquire (still not cheap);
6. Paint using tritium is safer for workers who apply the paint. Tritium is about 100,000 times less hazardous than radium if absorbed by the body and no expensive shielding is needed to prepare, handle and use tritium paint;
7. Tritium paints can also be made into various colors more effectively. Green is the conventional color because the human eye responds best to green. To change from the conventional green, more radioactive material is needed, which means phosphor is destroyed at a higher rate if using radium. But with tritium, when more tritium is used, the rate of loss does not change. Also, by using more tritium, the green painted lume can be made brighter than the green painted radium lume.
8. Because tritium is safer to use in larger quantities, it can be applied in larger amounts during manufacturing, lowering the cost of production by saving time.
If anyone knows of any inaccuracies, please comment and correct my error/s. Somewhat interesting to me, and it was more enjoyable than watching paint dry, which is what I would otherwise be doing as I am painting part of the house at the moment.
When talking about lume, we generally refer to lume that is made of radium, tritium or luminova. While only radium and tritium are radioactive, it’s easy to think of radioactive material as the source of the glow or illumination. But it is actually phosphor material that emits a glow, not the radioactive material. The radioactive material excites the phosphor, which then emits light. What makes the lume paint self-illuminating is the radioactive material that continuously emits energy.
As long as the material remains radioactive, the phosphor will continue to emit light. While the self-illuminating glow will be not as bright over time, it is because the radioactive material may be losing energy to excite the phosphor. But the paint will also glow less over time if the phosphor material deteriorates. If you shine a light on the lume and it glows, then it might not be glowing as brightly because the radioactive material has depleted. But if you shine a light on the lume and it doesn't glow, the radioactive material might still be just as radioactive but the phosphor material may have been destroyed.
Tritium is actually a gas, an isotope of hydrogen. Self-luminous paint production binds the tritium gas into a plastic binder, which is then combined with phosphor material and paint.
[Edit, per DanS below: "The polymer binder has hydrogen atoms in its molecular structure, and some of the naturally occurring isotopic hydrogen atoms are replaced with tritium in the molecular structure of the binder itself...Generally this "tritiation" is done to the precursor monomers prior to polymerization."]
There are many decisions to be made regarding the type of phosphor material that is used, as that will have a greater impact on how effective will be the paint.
The type of phosper is chosen based on how efficiently it converts beta-energy to light and the size of the phosphor particles. The size of the particles is important because it impacts how much radioactive material can be in the same material as well as how close the phosphor can be to the radioactive material, which can have a limited efficient range or distance.
In addition to the particle size of different phosphor, a silicate phosphor is preferred to a sulfide phosphor as the silicate based is more resistant to the harmful impacts of moisture and high energy radiation.
The choice of phosphor will determine the color of the paint:
Blue paint from calcium magnesium silicate, activated by titanium.
Green paint from zinc orthosilicate activated by manganese
Yellow paint from zinc cadmium sulfide activated by silver
Red paint from zinc phosphate activated by manganese
The differences we see in the color of aged lume, as well as how much it shrinks or how often certain references have moldy lume would seem to be the result of the type of phosphor used in the paint mixture as well as the plastic and solvent composition, more so than the radioactive material used.
Advantages of tritium over radium.
1. Tritium has low penetrating power and is thus safer for humans. Tritium is blocked by common materials like plastic and glass. Tritium is too weak to penetrate the skin. It must be inhaled or ingested to enter the body. Even then, huge quantities are needed to be extremely dangerous. Also, if tritium as a gas does enter the body, most of it will combine with oxygen to form water, which will exit the body in the urine, through moisture in the breath or as perspiration. If tritium gas is inhaled, much of it is immediately exhaled.
2. Radium is dangerous because if ingested in the body it lodges in bones and then radiates from there to cause damage to soft tissues. Radium emits gamma radiation, which continually radiates.
3. Radium also emits alpha particles, which destroy the phosphorescent crystals faster. Radium loses one-half of its original brightness each year following the production of the paint mixture. Tritium emits beta radiation, which does not destroy the phosphor. The rate of loss of brightness matches the rate of radioactive decay, about 6% per year.
4. Tritium has a half-life of 12 years whereas radium has a half-life of 1600 years. After 10 half-life periods, the material is considered not radioactive. This means tritium is radioactive for 120 years compared to radium, which lasts 16,000 years.
5. Tritium is a relatively lower cost to acquire (still not cheap);
6. Paint using tritium is safer for workers who apply the paint. Tritium is about 100,000 times less hazardous than radium if absorbed by the body and no expensive shielding is needed to prepare, handle and use tritium paint;
7. Tritium paints can also be made into various colors more effectively. Green is the conventional color because the human eye responds best to green. To change from the conventional green, more radioactive material is needed, which means phosphor is destroyed at a higher rate if using radium. But with tritium, when more tritium is used, the rate of loss does not change. Also, by using more tritium, the green painted lume can be made brighter than the green painted radium lume.
8. Because tritium is safer to use in larger quantities, it can be applied in larger amounts during manufacturing, lowering the cost of production by saving time.
If anyone knows of any inaccuracies, please comment and correct my error/s. Somewhat interesting to me, and it was more enjoyable than watching paint dry, which is what I would otherwise be doing as I am painting part of the house at the moment.
Edited:
