zOwie Omega Discussion Forum

: This answer to the fading problem is not as
: simple as just knowing the half-life of
: tritium. Luminova is not an element and
: therefore cannot have a half-life.

: I dunno if Speedies use tritium or not, I
: thought all radioactive element use for
: watches was discontinued years ago because
: of hazards to watch face makers. I had an
: old Rolex that I put under the geiger
: counter. (I used to be a science teacher!)
: It was still a strong beta emitter, but it
: did NOT glow at all. The face was rather
: faded and discolored, but it ran well.

: Anyway, Tritium is a rare isotope (1 part in
: 10^18) of hydrogen that has 2 extra neutrons
: in the nucleus. It's half-life is 12.32
: years.

: The glowing phenomenon on a tritium-faced watch
: is a function of SEVERAL things. First of
: all, the mechanism works like this: 1) The
: tritium atom releases a beta particle (beta
: part.= high speed electron)
: 2) The released beta particle (invis. to naked
: eye) runs into a phosphorous atom or similar
: compound.
: 3) This makes the phosphorous release a VISIBLE
: LIGHT photon. The face "glows".

: The amount of beta particles needed to make
: this happen is very small. MANY things could
: cause this hypothetical watch face to stop
: glowing: 1) Leaching of tritium to
: atmosphere
: 2) breakdown or loss of phos.compound
: 3) loss of adequate amount of beta particles
: (like how you mention)

: ...More than you wanted to know...

: MMC

Man thanks for the thorough explantion.

I guess if Luminova is not an element, it should theoretically have a longer life than tritium (all things being equal).

I remember reading that some watchmakers still use tritium (albeit in very small quantities) because it does not require a light source to "charge" the illumination. I guess this makes sense for watches used in applications where an external light source may not be readily available (i.e. outer space?).

If watchmakers are still using tritium, it's probably in really small quantities (could this be why they don't use "T-Swiss" very often in newer watches with Tritium?)

I'll definitely try to figure out if current Speedy Pros still use tritium.

Cheers!