A Day in the Life of a Subterranean Astronaut

As a particle physicist, I work in a unique environment: a mile underground.  I’m an Experiment Support Scientist with the Sanford Underground Research Facility (SURF), which means I support the various experiments we have throughout our entire underground campus.  As a scientist, I have a distinctive job because I don’t work on just one project, but rather on many projects helping out where I am needed.  The job can be busy, sometimes overwhelming, but it’s never boring.  Follow me through a typical day working underground at SURF.

Pulling into the lab parking lot this morning, I get to briefly watch the sunrise before I head inside.  The lab, situated in the gorgeous town of Lead, SD, surrounded by the Black Hills, is at the top of one of the tallest hills in town, which offers a great view of the surrounding area.

The morning starts pretty early at SURF; I have to be ready, dressed in my safety gear, and at the “cage” by 7am to go underground. My safety gear consists of steel-toed boots, a hard hat with a cap lamp, safety glasses, and coveralls with safety reflectors that make me more visible and protect my clothes from mine dust and dirt that I don’t want to track into the lab.  (My coveralls sport a Ghostbusters patch on each arm because if there’s one thing I know, it’s fashion.)  I also carry a W-65 self-rescuer on my belt, a device capable of filtering carbon monoxide out of the air to allow me to breathe if I ever need to escape in the unlikely event of an underground fire.

I head down an underground walkway to catch the cage.  At the end of the walkway, I take two brass tags with my name on them off of a tag board labeled “Science” and put one on a large tag board labeled “In” and the other one in my pocket.  This is one way we have to keep track of everyone that is underground at any given moment. 

The cage is essentially a large elevator that brings crews and materials underground to one of more than a dozen available levels underground at SURF.  The cage is capable of holding up to 10,000 pounds.  It can fit 36 people, although we never load more than 28 because at that point it’s already a tight fit.

This morning I’m riding the cage down with a handful of other scientists and several members of our Underground Maintenance Crew who work to keep the underground lab spaces habitable by bolting the rock, clearing the ventilation paths, and maintaining all of the infrastructure it takes to make a lab possible.  It’s a 12 minute ride to the 4850 Level, 4850 feet under our starting point.  The ride is dark - illuminated only by a couple cap lamps.  It can sometimes be noisy and it can sometimes be wet as water in the shaft above us drips into the cage.  But it’s a great chance to catch up with the crews, find out what’s going on for the day, and share a few laughs before the day really starts.

Now that we’re at the 4850L, my day’s activities start to get going.  I’m the Laboratory Coordinator today, as I am 2-3 days a week, which means that I need to round up the science crews as they come down, make sure they each have a solid plan for the day, coordinate with the other groups so that we can all get our jobs done without any destructive interference, and confirm that we can do so safely.  I gather all of the researchers from the 7am cage and give them a briefing and then give them each a chance to run through their day’s tasks to the group.  When the next science screw comes down at 7:30am, I repeat what the first crew told me and make sure there are no conflicts with the second crew.

It’s a full day underground; five research groups will be present on the 4850L and another one will be on the 4100L.  After finishing the morning coordination discussions, I catch a ride on an underground, battery-powered locomotive to one of the two major science campuses on this level, the Ross Campus.

At the Ross Campus I conduct a little training for a new researcher on how to safely handle lead bricks.  Don’t eat the lead bricks, don’t lick the lead bricks, don’t speak in harsh tones to the lead bricks, etc.  We use a lot of lead bricks underground for shielding.  We come a mile underground to conduct extremely sensitive experiments because only a mile of rock overhead can block out much of the noisy cosmic radiation experiments would experience on the surface.  We use lead bricks to further shield the experiments from radiation from local sources including the radioactive isotopes in the rock and concrete underground, the signals created by the various electronic equipment used in the experiments, and radioactive researchers - the human body puts out enough radiation on its own that it could overwhelm or even ruin some of our underground experiments.

Training done, I walk over to the Black Hills State University Underground Campus (BHUC) to help one of the researchers get together the materials she needs to swap out a radiation counting sample in one of the many low-background high-purity germanium (HPGe) detectors in that area.

Next I drop in to check on CASPAR (Compact Accelerator System for Performing Astrophysical Research).

I spend more time working with CASPAR than the other experiments because, in addition to being an Experiment Support Scientist at SURF, I’m also a PhD candidate at the South Dakota School of Mines & Technology (SD Mines) and CASPAR is my PhD project.  In CASPAR, an experiment in the field of nuclear astrophysics, we use a low-energy particle accelerator to reproduce the conditions inside the heart of a star, creating fusion reactions and observing the resultant particles.  We do so in an attempt to better understand how the stars synthesize new elements in the cosmos.  The juxtaposition of going underground to study the stars is why I sometimes refer to this group as Subterranean Astronauts.

While in CASPAR I help replace an accelerator target and review the radioactive sources (used for detector calibration) as part of our regular inventory program.

My trip takes me down the West Drift, so I am able to check on the SIGMA-V equipment.  SIGMA-V is an experiment being conducted to help understand processes that can be used to improve the efficiency and feasibility of geothermal energy production.  In contrast to most of the drifts underground, this area is well lit to help the researchers on that project work quickly and safely.

The area beyond SIGMA-V, however, is not lighted.  Aside from the line of overhead reflectors indicating my primary escape route in case of an emergency, there’s not much to pick up on camera.  I have to use my cap lamp to see where I’m going as I hike the remainder of the way to the Davis Campus.  This area is quiet and it can be very peaceful to walk through alone - my monastery a mile underground.

Approaching the Davis Campus, I wash the bottoms of my boots at two different stations so I don’t track any dirt into the Davis Campus. I decide to check in on the LUX-ZEPLIN (LZ) construction before I head into the clean space. So I head down another tunnel.

SURF is in the process of upgrading the space that the LUX (Large Underground Xenon dark matter search) experiment used to occupy so that it can fit the second-generation dark matter search experiment LZ.  That construction is nearly complete and today’s activities include installation of circulation lines and chemical passivation of the seams of the massive water tank that will be used as active shielding for the LZ detector.  I check in with the researchers working on those two tasks, do a quick inspection of the lab spaces, and then head back out to wash my boots one more time and go into the Davis Campus clean space.

To enter the clean space, I must wash my boots one more time, take off my dirty hard hat and rescue belt, and then gratefully remove my coveralls (which have acted like a personal sauna until now).  I now walk through a maze of doors that act as airlocks to keep out dirt and dust and I pick up a clean hard hat and clean lab shoes before entering the Davis Campus clean space.  The two major experiments housed at the Davis Campus require exemplary cleanliness and we go through great efforts to meet those requirements.  One of those experiments is LZ, but because it is under construction and separated from the rest of the Davis Campus by a plastic barrier, the most stringent cleanliness protocols do not apply right now.  (They will be reinstated once construction is completed and a deep clean can be performed).

The other experiment, the Majorana Demonstrator (MJD), an experiment aiding in the search for neutrinoless double-beta decay, is currently running and is very sensitive to any outside contaminant.  Researchers working directly on MJD must go through a second, even more stringent set of cleanliness protocols including putting on a hair net, booties over their lab shoes, two pairs of nitrile gloves, a Tyvek suit, a hood, a face mask, another pair of booties that clip into the suit, and tape around the gloves at the sleeve.  (When I have helped out in MJD, it is usually at this point that I realize I need to use the restroom.)  Once garbed up in this fashion, researchers can enter the Detector Room where they must discard their topmost pair of nitrile gloves and put on a new pair.

Inside the Davis Campus I check on the facility monitoring computer, do a quick update, and wipe down one of the stainless steel tables.  At this point I can finally sit down, pull out my laptop, and begin logging the daily lab activities.  I also need to complete the training paperwork from this morning’s training session, send some emails about safety inspections, and distribute notes from a meeting the day prior.

When it’s time for lunch I take a break from the computer work and while I eat I read a nuclear astrophysics paper for my PhD research.  No rest for the wicked(ly handsome).  Then a few of the researchers join me for a 1pm phone meeting wherein all of the science groups talk about their upcoming plans so we can coordinate efforts and make sure we have everything we need in place.  After a busy morning, the rest of the day goes by quietly.  I get a few calls from researchers needing me to coordinate resources and find transportation for some materials and I take the chance to get into some deeper projects I’ve been working on.  Before I know it, it’s time to pack up and get ready for the cage ride up.  The cage up is a bit more crowded than the cage down.  We shuffle in and take a 12 minute ride to the surface world, joking and talking through what needs to get done tomorrow.

It’s a sunny day on the surface and it’s good to get aboveground after a long day. 

But I’m looking forward to getting back to it tomorrow because, as we say at Sanford Lab, it’s always sunny on the 4850.