[Test-Equipment] Radioactive Tube Stamp

[J. Forster]

"Common sense" and "government" do NOT go together.

-John

==============

> On 7/3/2010 3:26 PM, Richard Knoppow wrote:
>>
>>       There are a lot of tubes with thoriated tungsten
>> filaments, I think most of the Eimac triode and tetrode
>> transmitting tubes have them.
>>       Thorium was used in some types of optical glass
>> especially for aerial photography lenses during WW-2. Some
>> of these had enough radiation to cause "browning" of the
>> glass over a period of many years. Thorium lends some
>> desirable optical qualities to the glass but it was
>> discontinued after the degree of radiation was discovered.
>> Some sources claim that the thorium was an accidental
>> ingredient, included as an impurity particularly to
>> lanthanum, but that is not the case: thorium was delibrately
>> used and is included in the formulas shown in the patents
>> issued to the National Bureau of Standards, where rare-earth
>> optical glass was developed. Even some high-performance
>> lenses for domestic rather than military use contained some
>> thorium elements. I don't know what the radiation levels of
>> these lenses are but I understand that the decay products of
>> thorium may be more hazardous than the thorium.
>>
>>
>> --
>> Richard Knoppow
> Thorium is indeed a radioactive element - IF - it is Thorium 232.
>
> The decay product of Thorium 232 is an alpha particle.  This is a not
> well understood method of decay to the "lay" person.
>
> Use the example of Thorium being added to a glass compound.  The glass
> in and of itself protects the individual from the alpha decay products.
> Alpha particles CANNOT penetrate "unbroken" skin, paper, or glass.
>
> Therefore they become a non-issue.
>
> The use of Thoriated Tungsten filaments in a vacuum tube does NOT
> present a danger to the user/operator - UNLESS the glass envelope is
> broken.  *IF* one were to "inhale" the alpha particles, THEN significant
> damage can be done.
>
> Significant is a "relative" term.  A "few" alpha particles being inhaled
> is not a *REAL* issue for the human body.  On the other hand, the
> inhalation of a LARGE amount IS.
>
> If someone should happen to break a Thoriated Tungsten filament tube,
> simply place the entirety of it and its parts wrapped in paper or such,
> (to prevent tearing the NEXT layer.), and place it in a "Zip-Loc" bag
> and dispose of it as normal trash.
>
> If it is done in this manner, it will NOT be a danger.
>
> That is unless one desires to contact "Hazardous Waste Officials".  IF
> you do so, all bets are off!
>
> Technically your home smoke detector should be considered hazardous
> waste, as also the compact fluorescent, or ANY  fluorescent light bulb.
>
> The smoke detector uses a radioactive substance called Americium.  The
> fluorescent bulbs contain very small amounts of mercury.
>
> There is "balance" in things.  One should not have sudden fears that are
> misplaced.   This is one of those areas that REQUIRES "common sense".
> Although one might consider that "common sense" is NOW uncommon!
>
> Bob - N0DGN
> ______________________________________________________________
> Test-Equipment mailing list
> Home: http://mailman.qth.net/mailman/listinfo/test-equipment
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Test-Equipment at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>