March 29, 2024

Building an Innovative Cross-Border Dark Matter Experiment Deep Underground – During a Pandemic

Staying safe while progressing science
As the pandemic settled in for its 4th or 3rd month, it struck Javier Tiffenberg, associate researcher at Fermilab and SENSEI partner, that the Fermilab teams prepared speculative setup, slated to start in 2020, required reconsidering.
Without a way to get to the website, the SENSEI group connected to SNOLAB to see if personnel were open to installing the hyper-sensitive experiment themselves with remote assistance from Fermilab. SNOLAB staff are currently familiar with the distinct challenges of setting up experiments in a tidy lab situated in a working mine. This time, they d be performing a weeks-long installation for an experiment they werent originally going to be a part of.
SNOLAB was video game.
” We will be their hands considering that they cant be here,” Silvia Scorza, research study scientist at SNOLAB, said of the viewpoint embraced for the task. Shes one of the SNOLAB workers whove taken on assisting install projects remotely during the pandemic.
” When the people at SNOLAB said they were interested in contributing to this and then from our side the engineers and professionals stated, Yeah, we can do this, I was very excited because I truly thought that this was coming together,” Tiffenberg said.

Without a way to get to the website, the SENSEI team reached out to SNOLAB to see if personnel were open to installing the hyper-sensitive experiment themselves with remote assistance from Fermilab. SNOLAB staff are currently familiar with the unique difficulties of installing experiments in a tidy laboratory located in a working mine. The SNOLAB physicists and specialists took a special class in electronics dealing with.
Scorza stated the mixture of work SNOLAB permits researchers to undertake– hands-on and analytical– provides them a more complete experience in experimental physics.” I think the reality that a group, a SNOLAB group of researchers, not initially very involved with the experiment, is able to progress with the underground installation shows that, first of all, physicists are extremely flexible,” Scorza said.

Greg Derylo, an engineer in the Particle Physics Division at Fermilab, developed the layout of SENSEI, dealt with the drafting group to make drawings of all the mechanical parts, and procured parts from on- and off-site maker shops. Because of COVID-19 restrictions results on access to Fermilabs campus, he also did many of the physical assembly of the experiment.
Derylo stated dismantling at Fermilab and re-assembling at SNOLAB was constantly part of the plan. But remote installation provided a brand-new issue.
” The genuine trick comes in terms of who is doing that assembly underground,” he stated. The SNOLAB physicists and service technicians took a special class in electronics managing.
Testing, testing, and a very pandemic-style celebration
Prior to the experiment could be put in SNOLABs hands, it needed to be evaluated and recorded.
” We tested whatever at Fermilab. We assembled everything in the same method as they would do it there,” Derylo stated.
The very first test was mechanical– putting together the outside shell of the experiment to confirm it would hold vacuum– and a thermal efficiency test. SENSEI counts on cryogenics to “run cold.” To do this, the Fermilab group placed on additional instrumentation to keep track of temperatures and run diagnostics. Both performed as anticipated.
In early fall 2020, the Fermilab group installed a set of test modules into the experiment, turned it on, cooled it down, ran it cold, and operated the modules. The readout went off without a hitch. The group celebrated– each member from their own location through Zoom– with champagne.
Documents and hand-modeling
Normally, the paperwork is more a series of tips than comprehensive directions, and group members can intuit the procedure or rely mainly on memory.
Producing directions for a team not familiar with the experiment needed next-level communication. That primarily meant creating documents with method more detail.
Fermilab engineer Greg Derylos labels show up on SENSEI. Derylo added the labels to aid with documents when he realized different employee had various meanings of front and back for the experiment. Credit: SNOLAB
They took benefit of their own assembly throughout testing due to the fact that the team knew the setup would be remote.
” We took photos of everything,” Tiffenberg said. “Having that documents was crucial.”
However coming up with it wasnt without difficulties. With several individuals documenting at various times due to the pandemic, interaction within the in-group likewise ended up being more crucial than usual. Various professionals had different viewpoints– literally.
” As it turns out, we actually had opposite definitions of what was the front of the setup,” Derylo said. The remedy? SENSEIs newest and one of its crucial parts: stick-on labels.
The group also constructed stop points into the paperwork. When a SNOLAB set reached one of these points, they might identify whether they had time to proceed to the next action in a shift or if they required explanation from the Fermilab team.
The very first draft was all set around the beginning of 2021. Derylo said the documentation was gotten into different areas and end up being around 70 pages. The document is comparable to an outline “peppered heavily with pictures.” Schematics for the vacuum system, the cooler system and electrical cabling were likewise offered, however werent part of the pamphlet.
” Then we took it apart however tried to keep as numerous pieces together as possible, and after that we shipped this to SNOLAB in January,” Tiffenberg said.
An ultraclean cleanroom in a working mine
Pandemic concerns aside, the procedure for installing experiments at SNOLABs underground center was always complex. After all, its a tidy lab that lies more than a mile underground– inside a working mine.
” Careful planning and preparation start at the surface,” Scorza stated.
There, at the beginning of the day, engineers, physicists, and specialists dressed like miners (plus masks and contact tracing badges for the pandemic) wait for “the cage,” a mining elevator to take them deep underground.
Entryway to the laboratory underground, looking towards the dirty side of the carwash: Every individual who goes into the laboratory on the other side must shower and change clothing. Every item that goes into the laboratory should go through the carwash. Credit: SNOLAB
The journey down takes less than five minutes. However then there is a journey thats practically a mile through a mine tunnel with a rail track running along it.
” So, view your step,” Scorza stated.
Individuals going into the tidy laboratory strip, shower and gown with brand-new tidy garments on the other side of the shower to avoid contamination. A “lab accountable planner” checks that the laboratory is cleared for work– examining oxygen levels, amongst other specifications. In a 10-hour day, this leaves about eight hours per shift to assemble the experiment.
A group of four, consisted of SNOLAB scientists and a technician, take turns and operate in sets to set up. (No one can be alone underground, and there are limitations on the maximum number of individuals to maintain physical distancing.).
” The product packaging is extremely particular,” Tiffenberg said.
In plain contrast from the mine, on the other side of the carwash is the lab itself, an ultra clean center. Credit: SNOLAB.
Every piece got must go through “the underground carwash,” Scorza said. Each product is triple-bagged and double-palleted to streamline the intricate procedure for unbagging and cleaning products prior to they can enter the cleanroom laboratory. On the other side of the carwash, the clean lab. For SENSEI, parts included pipe, cable television, vessel, copper pieces for the inner side, cryogenics, layers of lead and copper shielding, and the bell jar.
” When these things were developed, naturally, shipping whatever put together was not in the requirement list,” Tiffenberg said. “For the vast bulk of things that we delivered, everything was perfectly great.”.
Just a few minor plastic pieces– easily exchangeable– got loose and broke.
When whatever was opened and “looked great,” Tiffenberg stated it was a “big, huge relief.”.
Setup started April 19 and was completed in late summertime.
On Aug. 6, Steve Linden, a research study scientist at SNOLAB, continues to assemble SENSEI in the underground cleanroom. Credit: SNOLAB.
SNOLABs cleanroom is equipped with wi-fi and phones, interaction outside of the documentation takes place generally in weekly meetings. The strategy moved from week to week, depending on whether the team might make it underground because of schedule and COVID constraints.
Some days it involved extreme care: touching those skipper CCDs. Others, it included operating a crane to move lead protecting. Scorza stated the mixture of work SNOLAB enables scientists to undertake– hands-on and analytical– provides them a more total experience in speculative physics. “And, this is really fun. At least for me.”.
” I believe the fact that a team, a SNOLAB group of scientists, not initially extremely involved with the experiment, has the ability to advance with the underground setup reveals that, to start with, physicists are really versatile,” Scorza said. “And (its) a testament to how robust the plan for this experiment is. Chapeau to the Fermilab group.”.
Tiffenberg said he is grateful that the setup passed with no surprises or missteps.
” It took a long period of time to get to this scenario in which there are no surprises. At the beginning, everything felt, Okay, we are investing a lot of time adjusting, coordinating, evaluating things. And that took a long period of time. Now that things are moving, that time that we took there we appreciate, since now everything is surprise-free.”.
Though now that the experiment is taking information, a surprise in the kind of a clinical discovery would be a good reward.

To get to SNOLABs cleanroom, where the SENSEI experiment is to be housed, a trip more than a mile underground inside a working mine, pictured here, is needed. Credit: SNOLAB
In the search for dark matter particles, a tabletop experiment in the heart of a Canadian mine might suffice. The SENSEI collaboration utilizes skipper charged-couple devices, or CCDs, which are the most sensitive sensing units of their kind, dreamt up years ago and only recently realized.
The cooperation recently showed that the experiment has a delicate dark matter detector which it can decrease background rates in an underground experimental location at the Department of Energys Fermilab. Now, the collaboration is running a bigger, tremendously quieter, more delicate version of the experiment more than a mile underground at SNOLAB in Canada.
With the COVID-19 pandemic and the closure of the U.S.-Canada border, the experiment might have easily fallen back schedule in 2020. Rather, its in its commissioning phase– testing with about 20% of the target product the experiment will utilize when the external layers of protecting remain in location. Remarkable teamwork between physicists on both sides of the border made sure that it progressed on schedule.