The bizarre science behind the largest camera in the world

Leica don’t just make great cameras. They also contribute to the building of huge cameras too – including what’s described as “the largest camera in the world”, 1,400 metres below ground level at the CERN lab complex in Switzerland.

A project called Opera (no, not that Opera) has been underway for some years now, with the aim of observing the transformation of muon neutrinos into tau neutrinos. (No, I have no idea.)

These little beasties are so hard to find that they’re practically not there at all. They swish right through our planet at light speed. And the team of 150 physicists involved in the Opera project needed not just to see them, but see them doing their transformation trick. Apparently it’s quite something.

To do that, you need quite a camera. The sensor in this camera is a wall of 151,000 bricks that weighs 1,255 tonnes. The bricks are lined with 56 one-millimetre-thick alternating layers of lead and photographic film.

The focal length of this camera is just inches long. That neutrino transformation that everyone’s so interested in happens inside the bricks (hopefully), and the lead/film layers capture it as it happens. The flashes of energy released by the transformation get picked up and recorded.

Thinking about it, it sounds more like the world’s largest sunprint. With a billion microscopic suns.

You can read more in the PDF white paper downloadable from this page – it’s essentially an advert for Leica’s high-tech equipment that was used to ensure the wall of bricks was positioned in exactly the right spot, but the science stuff still makes for an interesting read.