Unknown tube of peculiar design

Accidentally I got a tube of rather peculiar design. I suspect it is some kind of sensor. There is no signs of company that made it, so it could be a prototype or member of very small production patch. 
It has only a handwritten number 87961 on it. 

Has anyone seen anything similar? What it could be? whe made these?

Here is a link to pictures:
 

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There ware markings that I didn't notice before, and this tube appears to be russian made ФЭУ-35 

It is a photo multiplier, that is extremely sensitive light sensor, which is still used in astronomy, physics etc. 

read here for more about photo multipliers

So, case is closed. Thank you.

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Here you can upload your photos: ФЭУ-35

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