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Radioactive lenses
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PostPosted: Fri Dec 25, 2009 9:24 pm    Post subject: Reply with quote
Hi Iwsy711,
all yours lenses are clean from radiation, I see no suspective
also Cosinon 1.2 (same as Porst Color Reflex) is not radioactive
Lucky You


PostPosted: Fri Dec 25, 2009 9:35 pm    Post subject: Reply with quote
semso wrote:
Hi Iwsy711,
all yours lenses are clean from radiation, I see no suspective
also Cosinon 1.2 (same as Porst Color Reflex) is not radioactive
Lucky You


Really? Smile
I did not try to filter them by radiation. The only fact make me uncomfortable is my suck skill Very Happy

Actually if there were any cheap good lenses that was marked as radioactive on the market that the owners want to get rid of it, I will buy it right now Very Happy But this never happened Twisted Evil


PostPosted: Fri Dec 25, 2009 9:51 pm    Post subject: Reply with quote
semso wrote:
I don"t know which element in lens is radioactive (Thorium? or other?)
But, rays goes through metal
THAT ARE NOT ALPHA RAYS like most of people hopes?!


As a scientific experiment, you should do the following:
0. Calibrate you detector with some source(maybe not ok for you)
1. Test you detector without any lenses or other material close to it. Record the rate or the dose.
2. Put lens close to it, and record the number.
3. Don't move the lens and the detector, put a paper in between of them and write down the number.
4. Put a Al plate in between and record the result
5. Put a lead plate in between and record the result.

If you find out the Al plate does not prevent anything, then the particles might be gamma or neutron. If the lead also don't work then it is neutron which seems like not possible. By the way, the normal energy alpha particle will only travel several centimeter in the air at most.

Sorry to act as a geek, but to get the truth, experiment is the best way to convince people.


PostPosted: Fri Dec 25, 2009 9:55 pm    Post subject: Reply with quote
It looks as if an impartial and non-biased discussion about this topic is not possible here. Crying or Very sad
This might be due to the relative complexity of the issue or maybe due to ignorance - anyhow, I will not continue "reading" this thread.

Anybody taking part in here should at least have basic knowledge about topics like the radioactive series of Thorium - then they wouldn't post things like "it's only an alpha emitter ...".
Also "it's not much so I don't care" does only gets me shaking my head - the cruy with radioactivity is that a) the "dose" is interesting but that still b) a "bad hit" could do harm even if the dose hasn't been really big

Nevertheless: Have "fun" in the continuing "discussion"! Crying or Very sad

Last edited by Cobalt60 on Fri Dec 25, 2009 9:59 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 9:59 pm    Post subject: Reply with quote
To Iwsy711:

0. I had a two of them, giving the same results!!
1.Done
2.Done
3.insufficient
4. Rays goes through metal cage (box) made from Ferum
5. Experiment will be continued

Dipl. ing elec. Semso


PostPosted: Fri Dec 25, 2009 10:06 pm    Post subject: Reply with quote
Hi lwsy711

I have just deleted one of your doubled posts Smile if you don't mind Smile

no worries -- I have read it few times if it's the same Smile

this thread is really interesting !

Would you buy Canon FD 55 f1.2 (it;s a hot lens) which contains Thorium?

Can this lens cause any harm?

Thanks

tf


PostPosted: Fri Dec 25, 2009 10:12 pm    Post subject: Reply with quote
semso wrote:
To Iwsy711:

0. I had a two of them, giving the same results!!
1.Done
2.Done
3.insufficient
4. Rays goes through metal cage (box) made from Ferum
5. Experiment will be continued

Dipl. ing elec. Semso


Semso,

You can always do something like this in youtube.....

http://www.youtube.com/watch?v=oL3D7FQTHXo

As everybody can see the thoriated element is in the back of the lens...


PostPosted: Fri Dec 25, 2009 10:18 pm    Post subject: Reply with quote
semso wrote:
To Iwsy711:

0. I had a two of them, giving the same results!!
1.Done
2.Done
3.insufficient
4. Rays goes through metal cage (box) made from Ferum
5. Experiment will be continued

Dipl. ing elec. Semso


Semso,

By saying "insufficient", do you mean the reading is low? And what is the distance of lens to the metal cage? If you have time, you should also test the cage alone. If all of these are done and you still reading high radiation, then I would say you got a source Evil or Very Mad


PostPosted: Fri Dec 25, 2009 10:19 pm    Post subject: Reply with quote
trifox wrote:
Hi lwsy711

I have just deleted one of your doubled posts Smile if you don't mind Smile

no worries -- I have read it few times if it's the same Smile

this thread is really interesting !

Would you buy Canon FD 55 f1.2 (it;s a hot lens) which contains Thorium?

Can this lens cause any harm?

Thanks

tf


tf,
Thanks so much, I was experiencing a network lag and trying to find how to delete the multiple post. Sorry for the trouble.

Wink

I would not worry about the lens contain Thorium, the radiation is weak and nobody want to add too much of such kind of expensive element into relative cheap lenses.

http://en.wikipedia.org/wiki/Thorium

If the major element is Thorium, then only possible major radiation product is alpha particle, because all the isotopes project beta have very short life time, which means most of them will decay into other stable particles after hours or days.

Last edited by lwsy711 on Fri Dec 25, 2009 10:29 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 10:21 pm    Post subject: Reply with quote
To Keysersoze27:
Thanks
That is exactly my radiation detector like by youtube (first one Pripyat)
The name of detector is the name of the closest village to Tchernobil?!


PostPosted: Fri Dec 25, 2009 10:26 pm    Post subject: Reply with quote
semso wrote:
To Keysersoze27:
Thanks
That is exactly my radiation detector like by youtube (first one Pripyat)
The name of detector is the name of the closest village to Tchernobil?!


Interesting...

Also I quote the guy from youtube:

Quote:
This is an SMC Takumar 55/1.8 that has a thorium doped lenses. Thorium was used to obtain larger refraction ratio and keep relatively low dispersion at the same time.

Radiation was measured with beta shields removed, so both gamma quants and beta particles were counted. Dose equivalent rate is almost 30uSv/h (200 times background radiation in my area). RKSB-104 (GORIN) shows only 20uSv/h because it has two G-M tubes on opposite sides of the casing, so only one tube was exposed to the radiation (the lens is 3-4cm in diameter). Polaron has two tubes also but both are placed on one side, so they both were exposed to the radiation.



Well I've got my 4 S-M-C Asahi lens in a distance of ~1.2m from my bed so... Shocked Laughing


PostPosted: Fri Dec 25, 2009 10:40 pm    Post subject: Reply with quote
To Keysersoze27:
As I can see only 1.4 from your 4 S-M-C is radioactive (as closer than 50cm)
semso


PostPosted: Fri Dec 25, 2009 10:46 pm    Post subject: Reply with quote
semso wrote:
To Keysersoze27:
As I can see only 1.4 from your 4 S-M-C is radioactive (as closer than 50cm)
semso


Thanks for the info Semso!!!!

.. the 1.4/50 is one of my favorites for it's creamy bokeh. Never going to sell it anyway Very Happy


PostPosted: Sat Dec 26, 2009 12:10 am    Post subject: Reply with quote
The Petkau Effect:

http://en.wikipedia.org/wiki/Petkau_effect

The book goes into detail about the effect around power plants with many maps and much data. Conclusion: no dose is safe; low-level long-term exposure is at least equally devastating as single high dose.

The Petkau Effect: The Devasting Effect of Nuclear Radiation on Human Health and the Environment (Paperback):

http://www.amazon.com/Petkau-Effect-Devasting-Radiation-Environment/dp/1568580193


PostPosted: Sat Dec 26, 2009 3:05 am    Post subject: Reply with quote
siriusdogstar wrote:
The Petkau Effect:

http://en.wikipedia.org/wiki/Petkau_effect

The book goes into detail about the effect around power plants with many maps and much data. Conclusion: no dose is safe; low-level long-term exposure is at least equally devastating as single high dose.

The Petkau Effect: The Devasting Effect of Nuclear Radiation on Human Health and the Environment (Paperback):

http://www.amazon.com/Petkau-Effect-Devasting-Radiation-Environment/dp/1568580193


Agree with this. But I think in this thread, I have a link that explains this in better detail. And according to wiki, the study was based on relative short time frame and high dose, and then assume the long time effect is the same as the acute effect which is the max estimation. In most case, the biological effect with the low dose rate of we accepted daily is estimated, not measured.


PostPosted: Sat Dec 26, 2009 5:10 am    Post subject: Reply with quote
lwsy711 wrote:
siriusdogstar wrote:
The Petkau Effect:

http://en.wikipedia.org/wiki/Petkau_effect

The book goes into detail about the effect around power plants with many maps and much data. Conclusion: no dose is safe; low-level long-term exposure is at least equally devastating as single high dose.

The Petkau Effect: The Devasting Effect of Nuclear Radiation on Human Health and the Environment (Paperback):

http://www.amazon.com/Petkau-Effect-Devasting-Radiation-Environment/dp/1568580193


Agree with this. But I think in this thread, I have a link that explains this in better detail. And according to wiki, the study was based on relative short time frame and high dose, and then assume the long time effect is the same as the acute effect which is the max estimation. In most case, the biological effect with the low dose rate of we accepted daily is estimated, not measured.



The book is translation of original German book "Die sanften Morder":
http://www.abebooks.de/servlet/BookDetailsPL?bi=1395832648

Includes long-term studies with maps showing Forest Decline for many miles around nuclear power plants and uranium mines. There are numerous other long-term examples verifying the Petkau effect.

my mathematics orientation tells me for small targets in a large space odds for a hit with random aim are much better and more widespread given multiple shots.


PostPosted: Sat Dec 26, 2009 7:57 am    Post subject: Thank Reply with quote
Thanks everyone for so many replies. I really appreciate your input.

I did not start the topic to find out whether radion is harmfull to humans. The main purpose was to find out if my Fujinon 55mm F1.8 (non EBC) contains thorium. I have a brand new copy of this lens that was never used and I like the picture quality of this particual lens. If the lens contains thorium I would sell it straight away, if not I would like to keep it.

Cheers,

Snajper


PostPosted: Sat Dec 26, 2009 3:54 pm    Post subject: Reply with quote
siriusdogstar wrote:


The book is translation of original German book "Die sanften Morder":
http://www.abebooks.de/servlet/BookDetailsPL?bi=1395832648

Includes long-term studies with maps showing Forest Decline for many miles around nuclear power plants and uranium mines. There are numerous other long-term examples verifying the Petkau effect.

my mathematics orientation tells me for small targets in a large space odds for a hit with random aim are much better and more widespread given multiple shots.


Sorry, I think there is some misunderstanding here. I did not say the effect or the test they do is correct or not(as a scientist, one should doubt about any result first before believe it). What I am saying is, in practice we can not detect the damage to human body with long term daily radiation. But we do know the damage caused by acute radiation, so the max damage for long term radiation should not exceed the acute dose does. This agrees with the Petkau effect.

In my understanding, the radiation out side of nuclear power plants and uranium mines are mainly come from neutron, and in this topic, we are mainly concentrating on the ionizing radiation(alpha, beta, gamma). The reaction is different and the harm to human body is different. By the way, there are also a lot of neutrinos coming out of nuclear power plant, but we don't need to care about them because, the reaction cross section is so small that the earth is transparent to them Very Happy , but physicist is building detectors near nuclear power plant to study this particle.


Sorry, seems like I am going too far from the topic here. I still don't believe the "radiation lens" is harmful for people if one don't swallow the lens. And for the DSLR sensor, I think it is a good idea to mount a "radiation lens" and normal lens to make a black picture to see the noise level difference. Basically the sensor is also a gamma detector that detects low energy gammas.

P.S. Sorry, I don't fully understand this:

Quote:
my mathematics orientation tells me for small targets in a large space odds for a hit with random aim are much better and more widespread given multiple shots.


Are you talking about particles?


Cheers,
Wei Very Happy


PostPosted: Sat Dec 26, 2009 4:02 pm    Post subject: Re: Thank Reply with quote
snajper wrote:
Thanks everyone for so many replies. I really appreciate your input.

I did not start the topic to find out whether radion is harmfull to humans. The main purpose was to find out if my Fujinon 55mm F1.8 (non EBC) contains thorium. I have a brand new copy of this lens that was never used and I like the picture quality of this particual lens. If the lens contains thorium I would sell it straight away, if not I would like to keep it.

Cheers,

Snajper


Snajper,
You are welcome!
Kind of don't understand why you want to sell it straight away while you don't want to know "whether radion is harmfull to humans" and you like the IQ.......My suggestion is keep it or maybe keep it in you basement and as soon as you got solid proof this is harmful to human then sell it Very Happy
(Unfortunately, if it is a lens I want, or I would change me suggestion to "Sell it to me right now!" Twisted Evil Twisted Evil Twisted Evil Twisted Evil )

Cheers,
Wei


PostPosted: Sun Dec 27, 2009 6:41 am    Post subject: Reply with quote
Oh man. I should stop licking my lenses y/n?


PostPosted: Sun Dec 27, 2009 7:16 am    Post subject: Reply with quote
lwsy711 wrote:
trifox wrote:
Hi lwsy711

I have just deleted one of your doubled posts Smile if you don't mind Smile

no worries -- I have read it few times if it's the same Smile

this thread is really interesting !

Would you buy Canon FD 55 f1.2 (it;s a hot lens) which contains Thorium?

Can this lens cause any harm?

Thanks

tf


tf,
Thanks so much, I was experiencing a network lag and trying to find how to delete the multiple post. Sorry for the trouble.

Wink

I would not worry about the lens contain Thorium, the radiation is weak and nobody want to add too much of such kind of expensive element into relative cheap lenses.

http://en.wikipedia.org/wiki/Thorium

If the major element is Thorium, then only possible major radiation product is alpha particle, because all the isotopes project beta have very short life time, which means most of them will decay into other stable particles after hours or days.


IIRC one of the decay products (Second?) emits gamma.


PostPosted: Sun Dec 27, 2009 9:29 am    Post subject: a link Reply with quote
http://docs.google.com/viewer?a=v&q=cache:SWk6oaXMcgEJ:www.ead.anl.gov/pub/doc/Thorium.pdf+ThO2+radioactive+alpha+beta+gamma+thorium+dioxide&hl=en&pid=bl&srcid=ADGEESjzF0jRSamDb4HTmNXlS8uenNw20XQpOKVgcesDmpPydm__ksV1OJ6lLGIqTHEhl6aVv-29JYY6kxHD8RaU3fBn5qGk168nHcMFaHUKgStnwRLrLKMDXZax-61gimwgl-Cig0ZU&sig=AHIEtbTToeQCBel6JWy1A7rqGuMevh7bJQ

A nice little link for information about Thorium.


PostPosted: Sun Dec 27, 2009 9:46 am    Post subject: Reply with quote
Mike Deep wrote:
lwsy711 wrote:


I would not worry about the lens contain Thorium, the radiation is weak and nobody want to add too much of such kind of expensive element into relative cheap lenses.

http://en.wikipedia.org/wiki/Thorium

If the major element is Thorium, then only possible major radiation product is alpha particle, because all the isotopes project beta have very short life time, which means most of them will decay into other stable particles after hours or days.


IIRC one of the decay products (Second?) emits gamma.


This point is made by the Argonne National Laboratory

http://www.ead.anl.gov/pub/doc/natural-decay-series.pdf

(same source as Anu's link) who say...

In some situations, it may be necessary to add the radiological risk identified for a given radionuclide to that of its parent radionuclide to properly represent the total risk. For example, the radiological risk for thorium-232 is comprised of the risk for thorium-232 plus the risk for radium-228.

Thorium-232 decays (alpha emission) to Radium-228 which decays (beta-emission) to Actinium-228 which is a gamma-emitter.


PostPosted: Sun Dec 27, 2009 12:41 pm    Post subject: Reply with quote
Yes, there are two additional reasons of radiation:

1. products of the decay (which can be more radioactive, than the original thorium and because of that, the older lens is, the more radioactivity it produces)

2. other substances - old thoriated glass often contains thorium salts (manufacturers weren't able to create really pure thorium), which are more radioactive, than the thorium itself... newer lenses contain less of these salts, so newer thorium lenses are less radioactive (that's true for lanthanum lenses too - new lanthanum lenses are almost not radioactive)


PostPosted: Mon Dec 28, 2009 6:05 pm    Post subject: Reply with quote
Thanks for the useful links you provided. I think the link Anu has provided explains a lot of this issue and in the last table, it shows what is the risk of cancer for Th232 is. To me, it should be much less of increasing the chance of cancer for the lens radiation comparing to inhalation and ingestion radiation. So the lens radiation is not a big concern for me.

John,
That's true in the Th232 decay chain, it will also emit gamma and beta, totally when it comes to a stable particle, it will emit 6 alpha and 4 beta(don't know the number of gamma, need a careful calculation). To us the more important thing is how much beta, alpha and gamma per second, to calculate this, we need to weight each decay by the life time of the particle. Not very hard to do but not in the mood to do(I hurt myself yesterday Sad ). Then to evaluate the radiation damage to human, we also need to know the energy distribution and distance of exposure. So in one word, to calculate the radiation damage of Th232 in theory is not easy, a simulation is the best way.

A much more easier and better way to test this is just take the radiation lens, camera and detector.
1. put detector on different distance and read the number, If one see the number still very high when the detector is like 10cm away, then there is gamma or beta in the radiation product. Then one can try the shielding material in between and see what the particle is(to separate gamma and beta).
2. Put the lens on the camera and measure the radiation near the viewfinder and the back of the camera. If you see high rate, then there is radiation, and send it to me Very Happy if not, nothing to worry about, right?

Regards,
Wei
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