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Posts Tagged ‘Day in the Life’

Going underground most days for work is probably the weirdest-sounding this about this job. At Laboratori Nazionali del Gran Sasso, we use the lab to be underground because of the protection it affords us from cosmic rays, weather, and other disruptions, and with it we get a shorthand description of all the weirdness of lab life. It’s all just “underground.”

ss17bis

The last kilometer of road before reaching the above-ground labs of LNGS

Some labs for low background physics are in mines, like SURF where fellow Quantum Diariest Sally Shaw works. One of the great things about LNGS is that we’re located off a highway tunnel, so it’s relatively easy to reach the lab: we just drive in. There’s a regular shuttle schedule every day, even weekends. When there are snowstorms that close parts of the highway, the shuttle still goes, it just takes a longer route all the way to the next easy exit. The ride is a particularly good time to start drafting blog posts. On days when the shuttle schedule is inconvenient or our work is unpredictable, we can drive individual cars, provided they’ve passed emissions standards.

The guards underground keep a running list of all the people underground at any time, just like in a mine. So, each time I enter or leave, I give my name to the guards. This leads to some fun interactions where Italian speakers try to pronounce names from all over. I didn’t think too much of it before I got here, but in retrospect I had expected that any name of European etymology would be easy, and others somewhat more difficult. In fact, the difficult names are those that don’t end in vowels: “GladStone” become “Glad-eh-Stone-eh”. But longer vowel-filled names are fine, and easy to pronounce, even though they’re sometimes just waved off as “the long one” with a gesture.

There’s constantly water dripping in the tunnel. Every experiment has to be housed in something waterproof, and gutters line all the hallways, usually with algae growing in them. The walls are coated with waterproofing, more to keep any potential chemical spill from us from getting into the local groundwater than to keep the water off our experiments. When we walk from the tunnel entrance to the experimental halls, the cue for me to don a hardhat is the first drip on my head from the ceiling. Somehow, it’s always right next to the shuttle stop, no matter where the shuttle parks.

And, because this is Italy, the side room for emergencies has a bathroom and a coffee machine. There’s probably emergency air tanks too, but the important thing is the coffee machine, to stave off epic caffeine withdrawal headaches. And of course, “coffee” means “espresso” unless otherwise stated– but that’s another whole post right there.

When I meet people in the neighboring villages, at the gym or buying groceries or whatever, they always ask what an “American girl” is doing so far away from the cities, and “lavoro a Laboratorio Gran Sasso” is immediately understood. The lab is even the economic engine that’s kept the nearest village alive: it has restaurants, hotels, and rental apartments all catering to people from the lab (and the local ski lift), but no grocery stores, ATMs, gyms, or post offices that would make life more convenient for long-term residents.

Every once in a while, when someone mentions going underground, I can’t help thinking back to the song “Underground” from the movie Labyrinth that I saw too many times growing up. Labyrinth and The Princess Bride were the “Frozen” of my childhood (despite not passing the Bechtel test).

Just like Sarah, my adventures underground are alternately shocking and exactly what I expected from the stories, and filled with logic puzzles and funny characters. Even my first night here, when I was delirious with jetlag, I saw a black cat scamper across a deserted medieval street, and heard the clock tower strike 13 times. And just like Wesley, “it was a fine time for me, I was learning to fence, to fight–anything anyone would teach me–” (except that in my case it’s more soldering, cryogenics plumbing, and ping-pong, and less fighting). The day hasn’t arrived where the Dread Pirate Roberts calls me to his office and gives me a professorship.

And now the shuttle has arrived back to the office, so we’re done. Ciao, a dopo.

(ps the clock striking 13 times was because it has separate tones for the hour and the 15-minute chunks. The 13 was really 11+2 for 11:30.)

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Sonic Copper Cleaning

Saturday, February 7th, 2015

IMG_7979Today we cleaned parts to go into the detector using a sci-fi piece of machinery called a “sonic bath”.

On CUORE, we’re looking for a faint signal of radioactivity. That means we can’t let anything swamp that signal: we have to clean away the normal low-level of dirt present in the atmosphere and biological systems. Even something as normal as a banana has so much naturally-occurring radiation that the “banana-year” is a (someone irreverent and imprecise) unit of measurement for backgrounds of dark matter experiments.

The parts we’re cleaning will be guide tubes for a calibration system. Through them, we’ll place wires close to the detector, then remove them again when it’s time for the main data taking. The calibration wires have a measured amount of radioactivity, and we use that known signal to calibrate the other signals within CUORE.

We used a sonic bath to clean the parts: they’re in a bag with soap water, inside a larger tub filled with tap water. To agitate everything (like the dasher in a clothes washer) the machine uses sound. It’s a bit like the little machines that some people use to clean their contact lenses, but larger: about the size of a laundry room sink, or a restaurant kitchen sink.

IMG_8002My favorite part of the process was the warning on the side: running with an empty bath could cause burnout of the ultrasonic coupler. “The ultrasonic coupler” sound like something out of science fiction: like a combination of “sonic screwdriver” and “flux capacitor”. But it’s not fiction– this is just what we need to do for our daily work!

The noise it makes sounds a bit like an electric fly zapper: a low level electric buzz and cackle, with a faint hiss hinting that there’s something higher pitched above that. It’s practically impossible to hear the main frequency because it’s pitched so much higher than human hearing: the noise is at 30-40kHz, and a child can usually hear as high as 20kHz. Some of the lower resonances fall into an audible range, which is what makes it sound like there’s more going on than I can hear.

In the smaller machine (about the size of a bathroom sink), the agitation noise was more audible, almost headache-inducing in long doses. Since I just watched the fourth Harry Potter movie, it reminded me of the recorded mermaid message: you can only hear it when you’re underwater. If you’re in air, it sounds like a screech instead of a message. Knowing the line between science fiction and fact, I didn’t actually stick my ear in the water (and we wore earplugs in the lab).

IMG_7992There’s a funny effect with some of the bubbles in the tub. They get caught in vibrational nodes within the water, so even though they’re clearly made of air, they don’t rise to the top. It’s like an atom trap made of lasers holding a single atom in place, except this works at a macroscopic level so it’s more intuitive. Seeing the modes in action is a little reward for having worked through all those Jackson problem sets where we deconvolved arbitrary functions in various ways.

When the parts come out at the end, and after we repeat the process with some citric acid (like what you find in lemon juice) and then rinse everything, the rods are a completely different color. They’ve gone from a dead-leaf brown to a peachy pink, all shiny and bright and hopeful. It’s a clean start for a new detector. We preserved the clean exteriors by sealing them in vacuum bags,  and told the chem lab supervisor we were done for the day.

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