Radioactive thermal imager?

[mikeselectricstuff]

This EEV P4428 has "radioactive material" stickers on the camera and case - can't see any reason why a TIC would use anything radioactive.
Maybe it got contaminated, or someone just wanted to reduce risk of it getting stolen..?
It does look like it's just tape stuck on rather than original labels.

http://www.ebay.co.uk/itm/EEV-P-4428-Thermal-Imaging-Infrared-Camera-/201801715045?hash=item2efc51cd65:g:DDIAAOSw2xRYkHyU

[Bill W]

The tale behind this is that early TIC lenses had Thorium in the anti-refelction coatings, and so were mild alpha emitters.

This one, and indeed all P4428 DO NOT have Thorium coatings but once the Navy had got the idea that 'thermal cameras might be radioactive' (the older P4228 were, as were the bigger lenses in the P4430) they just put stickers on regardless !

The tube faceplates also had Thorium coatings for a bit longer, it was even said    that this helped balance the helium loss from the 'soft' tubes.

regards
Bill

[joeqsmith]

I have an old camera that uses thorium fluoride for the optics.  They warn you about handling them. 

I'm always curious with the people who buy used mass spec and optical equipment like this, how do you know what materials it has in it or worse, in the case of a mass spec, what it was used for.

[joeqsmith]

I think they have to have warnings on them now and I believe they changed the percentage that could be used.

[Ultrapurple]

I know nothing about thorium fluoride - what is its spectral range? Any chance of a picture of the relevant bits and pieces and some info on the camera?

[joeqsmith]

A few hits from Google:

https://materion.com/resource-center/product-data-and-related-literature/inorganic-chemicals/fluorides/thorium-fluoride-for-optical-coating

http://www.thoriumsafety.com/

More general:

https://www.photonics.com/EDU/Handbook.aspx?AID=25493

[joeqsmith]

Here's the camera in operation

https://youtu.be/JlY4v3ruT3g

[Bill W]

I know nothing about thorium fluoride - what is its spectral range? Any chance of a picture of the relevant bits and pieces and some info on the camera?

Thoruim Fluoride is used as an anti-reflection coating, not a bulk optical material.
May date the camera back to 1980's at a guess.

regards
Bill