Greater Minnesota job market / employment news

[Tom H.]

Time to go read up on extraction techniques for helium. Hope these leases can provide meaningful benefits for all Minnesotans.

And as someone who used to work as a physicist in the Soudan Underground Lab, I can arrest to the acute need for helium in scientific research.

[angrysuburbanite]

What even happens at the Soudan lab? The tour guide I was with there many years ago mentioned it a bunch of times, it sounds interesting.

[Tom H.]

There have been a number of experiments housed in the lab over the years. Basically, any experiment which requires ultra-low background / shielding from cosmic radiation is a good fit for an underground lab. Natural radioactivity in the rock overburden is then the background signal that you largely need to control for.

One of the earliest experiments (1980s, I think) was a proton-decay search, which literally just consisted of literal tons of water interspersed with scintillator detectors, looking for a signature of proton decay. It may even still be running today, since it has basically no overhead and basically runs itself. (Spoiler alert, they haven't found proton decay.)

The main experiment that Soudan was known for was MINOS, which measured a beam of neutrinos shot toward Soudan from Fermilab in Chicago. The idea was to measure the oscillation of neutrino flavors as it travels the few hundred miles between the source and the detector, as well as to look for some other details important to neutrino physics. You may remember that a similar experimental setup in Europe erroneously claimed to discover neutrinos travelling faster than light back in 2011 (it was a clock synchronization error, I think). MINOS was quick to say they couldn't replicate the result, and the error was discovered shortly thereafter.

The experiment I worked on was CDMS - Cryogenic Dark Matter Search. We were looking to directly detect dark matter particle collisions using ultra-cold detectors, which require a very low particle background to have the sensitivity necessary to search for dark matter collisions. While I was there, we were working to upgrade our technology to a next generation of detectors known as SuperCDMS, which are now deployed in an even deeper and lower-background facility near Sudbury, Ontario called SNOLAB. (Spoiler alert, we still haven't detected dark matter yet.)

UPDATE: I googled it and looks like the lab is closed down now, and experiments dismantled. I knew that most of the lab staff had moved on in recent years, but I guess the lab is gone now - makes me sadder than I had expected to be.

I highly recommend taking the mine tour if you ever find yourself in Soudan. It's truly incredible, and it's all that's available now that there's no lab to visit for a science tour :'(

[angrysuburbanite]

Very fascinating, though it is sad that the lab closed (It looks like it closed a year or so after I took a tour there). Thanks for sharing!

[tedlanda2571]

The Soudan Mine tour is a Minnesota must do. The cage elevator is original and is kept in fantastic working order. Watching it work from the surface is interesting on its own. Once at the bottom you ride a mine train about a mile laterally.

Next time you look at the Minneapolis skyline, realize that if you stacked 3 IDS Center's on top of each other, they would barely poke above the surface if placed at the bottom of the mine.