Fermilab event shows kids fast-paced science experiments

Plans for a new accelerator laboratory began in April 1963. Subsequent Aprils brought the completion of the Central Laboratory Building, the installation of the final Main Ring magnet and other important milestones. Read on.

Since it began taking data in 2009, the MINERvA collaboration has published roughly 20 papers on neutrino-nucleus interactions. It’s a strong, promising start for the experiment, and scientist Laura Fields, who started her new two-year term as MINERvA co-spokesperson on March 17, intends to keep up the momentum.

Fields offers kudos to current MINERvA co-spokesperson, Fermilab scientist Debbie Harris, and her predecessor, University of Rochester scientist Kevin McFarland, for the experiment’s success.

“The previous spokespeople put the experiment on a really good path,” Fields said, half-joking that “my first goal is not to break all the good things they’ve done.”

In addition to continuing the push to publish, Fields will work to help finish MINERvA’s current data-taking run, which uses the medium-energy NuMI beam at Fermilab to produce neutrino interactions in the detector. In previous years, MINERvA used a low-energy NuMI beam.

“It’s really a boon for MINERvA,” Fields said. With a higher-energy beam, scientists get more neutrino interactions. “We can get a lot of good stuff out of that data.”

Fields received her Ph.D. from Cornell University under the supervision of Ritchie Patterson and, in 2010, went on to complete a Northwestern University postdoc under professor Heidi Schellman (now at Oregon State University) conducting research for MINERvA and DUNE. Fields led the team that published the experiment’s first two papers in 2013. In 2015, she joined Fermilab as an associate scientist in the Scientific Computing Division.

“Laura has been crucial to MINERvA’s physics program since she joined the experiment as a postdoc,” McFarland said. “She has been an effective mentor to so many of MINERvA’s students.”

Indeed, as co-spokesperson, Fields will work to actively support MINERvA’s early-career researchers by making sure their work is showcased in experiment publications.

“I’m looking forward to interacting more with the students and postdocs of MINERvA and to helping them get all we can out of our data,” she said. “I’m also going to work to be a good role model for the women in our collaboration.”

With Fields’ election as MINERvA’s co-spokesperson, both of Fermilab’s operating short-baseline neutrino experiments are now led by women. The MINERvA experiment is led by Fields and Harris, and the MicroBooNE experiment is led by Yale University-Fermilab scientist Bonnie Fleming and Fermilab scientist Sam Zeller.

“I am looking forward to the day when it will not be a big deal for there to be two women spokespersons of an experiment,” Harris said. “In the meantime I am enjoying the buzz about this and grateful to Kevin for deciding to step down in order to let a new person with new ideas lead the collaboration.”

McFarland said he feels the same way about his successor.

“As one of my hometown’s heroes famously said, ‘Failure is impossible.’ Susan B. Anthony said this not as a statement of optimism, but because she knew with certainty that all factors pointed to the eventual success of her cause,” McFarland said. “With MINERvA’s rich data set and Laura leading us, I feel the same way about the success of MINERvA’s physics program.”

 

Sometimes big questions require big tools. That’s why a global community of scientists designed and built gigantic detectors to monitor the high-energy particle collisions generated by CERN’s Large Hadron Collider in Geneva, Switzerland. From these collisions, scientists can retrace the footsteps of the Big Bang and search for new properties of nature.

The CMS experiment is one such detector. In 2012, it co-discovered the elusive Higgs boson with its sister experiment, ATLAS. Now, CMS scientists want to push beyond the known laws of physics and search for new phenomena that could help answer fundamental questions about our universe. But to do this, the CMS detector needed an upgrade.

“Just like any other electronic device, over time parts of our detector wear down,” said Steve Nahn, a researcher in the U.S. Department of Energy’s Fermilab and the U.S. project manager for the CMS detector upgrades. “We’ve been planning and designing this upgrade since shortly after our experiment first started collecting data in 2010.”

The CMS detector is built like a giant onion. It contains layers of instruments that track the trajectory, energy and momentum of particles produced in the LHC’s collisions. The vast majority of the sensors in the massive detector are packed into its center, within what is called the pixel detector. The CMS pixel detector uses sensors like those inside digital cameras but with a lightning fast shutter speed: In three dimensions, they take 40 million pictures every second.

For the last several years, scientists and engineers at Fermilab and 21 U.S. universities have been assembling and testing a new pixel detector to replace the current one as part of the CMS upgrade, with funding provided by the Department of Energy Office of Science and National Science Foundation.

The pixel detector consists of three sections: the innermost barrel section and two end caps called the forward pixel detectors. The tiered and can-like structure gives scientists a near-complete sphere of coverage around the collision point. Because the three pixel detectors fit on the beam pipe like three bulky bracelets, engineers designed each component as two half-moons, which latch together to form a ring around the beam pipe during the insertion process.

Over time, scientists have increased the rate of particle collisions at the LHC. In 2016 alone, the LHC produced about as many collisions as it had in the three years of its first run. To be able to differentiate between dozens of simultaneous collisions, CMS needed a brand new pixel detector.

The upgrade packs even more sensors into the heart of the CMS detector. It’s as if CMS graduated from a 66-megapixel camera to a 124-megapixel camera.

Each of the two forward pixel detectors is a mosaic of 672 silicon sensors, robust electronics and bundles of cables and optical fibers that feed electricity and instructions in and carry raw data out, according to Marco Verzocchi, a Fermilab researcher on the CMS experiment.

The multipart, 6.5-meter-long pixel detector is as delicate as raw spaghetti. Installing the new components into a gap the size of a manhole required more than just finesse. It required months of planning and extreme coordination.

“We practiced this installation on mock-ups of our detector many times,” said Greg Derylo, an engineer at Fermilab. “By the time we got to the actual installation, we knew exactly how we needed to slide this new component into the heart of CMS.”

The most difficult part was maneuvering the delicate components around the pre-existing structures inside the CMS experiment.

“In total, the full three-part pixel detector consists of six separate segments, which fit together like a three-dimensional cylindrical puzzle around the beam pipe,” said Stephanie Timpone, a Fermilab engineer. “Inserting the pieces in the right positions and right order without touching any of the pre-existing supports and protections was a well-choreographed dance.”

For engineers like Timpone and Derylo, installing the pixel detector was the last step of a six-year process. But for the scientists working on the CMS experiment, it was just the beginning.

“Now we have to make it work,” said Stefanos Leontsinis, a postdoctoral researcher at the University of Colorado, Boulder. “We’ll spend the next several weeks testing the components and preparing for the LHC restart.”

View a photo gallery of the pixel detector installation in symmetry magazine.

How long have you worked at Fermilab?
It will be five years this summer. I started in 2012. Before that I had been working in private industry for about five years. It was a small company, about 30 or 40 people, and we were basically suppliers for places like Fermilab. Now I get to be the end user for these products, which is kind of nice.

What do you do as a lab mechanical engineer?
I work in the Technical Division Test and Instrumentation Department, mostly testing magnets. Right now, I’m working on the relocation of a test stand that was at the Central Helium Liquefier building. Now it’s going to HAB, the Heavy Assembly Building. We’re modifying the test stand to test the Mu2e transport solenoid production magnets.

What’s a typical day for you?
It varies day to day, depending on what state we’re in. Usually I’ll come into work, meet with technicians about modifications over at HAB, figure out the day’s work. Then I’ll work on design work, analysis or engineering notes. Later I’ll meet with the techs again to see if there are any issues or problems.

What do you like about working at Fermilab?
I like meeting people who come from all over the world, the variety of people. I also appreciate the overall concentration of intellect at Fermilab. It’s a unique opportunity to be working among so many different smart people and on so many different things outside my expertise.

You recently finished a term on the Engineering Advisory Committee. What was that like?
I was working with Paul Czarapata and Chris Mossey as part of the EAC. Various engineers got together to discuss different engineering-related issues with the director. I really liked that because it gave you an opportunity to look at engineering at the lab with a higher, 30,000-foot view. It was a good experience, because it takes you out of your bubble and lets you see how other people work and what kinds of issues they run into.

What do you do outside of work?
I play guitar in a band, the Blue Freedom Band. It’s a cover band that I play in with friends. We perform mostly in bars in the southwest suburbs or festivals. A lot of the people I play with grew up in that area, so they’ll book gigs different places around there.

Lately I’ve been taking improv classes in Chicago. It’s so much fun. My sister and I take classes together. We wanted something for us to be able to do together since we live far away from each other. We did some classes at Second City, and now we’re trying to do classes at iO.

Half a dozen local retirees gathered in the cold on a dreary weekday afternoon at Fermilab.

They were on the hunt for three invasive species: multiflora rose, buckthorn and honeysuckle. Carrying saws, hedge clippers and herbicides, the volunteers were ready to take on the invading plants. Chatting amiably with one another, they cut down invasive plants and carefully spritzed the roots with herbicide to prevent the plants from growing back.

Protective gear such as knee pads, thick gloves and safety glasses held thorns and branches at bay and prevented contact with the herbicides (which the volunteers are licensed to use by the state of Illinois).

After several hours, they departed, leaving behind a landscape where native species could once again flourish.

The volunteers who work with Fermilab ecologist Ryan Campbell to do this bushwhacking every winter are generally retirees who become involved because they find the work of preservation satisfying. For many of the volunteers, it becomes more than just a way to pass the time, and conservation becomes an active part of their life.

Penny Kasper, formerly a Fermilab physicist, is the president of Fermilab Natural Areas. Under her watch, the nonprofit organization helps conservation efforts across Fermilab’s 6,800 acres.

Kasper, like other volunteers, said she just got “sucked into it.” Some volunteers become so dedicated to the mission of removing invasive species that they carry hedge clippers with them in their car, just in case. Those pesky invasive species are a threat that requires dedicated action.

“If a habitat is not lost through development of some kind, the second greatest threat to habitat quality is invasive species,” Campbell said.

Invasive species are usually foreign or exotic species that are relatively new to the area. Because these plants and animals aren’t local, they don’t often have predators to hold them in check, and so they become out of control. For example, the brown tree snake has decimated the bird population of Guam because it has no natural predators there. This doesn’t happen in every case: Peaches are originally from China but aren’t invasive, even in Georgia, where they grow well.

“One thing that’s kind of a big misconception is that all non-native species are invasive, or all exotic plants are invasive,” Campbell said. “That’s not true. You can even have some native species that we would consider invasive depending on the situation.”

The main characteristic of invasive species is that they out-compete others in the area, like weeds in a garden. Multiflora rose, an invasive winding vine peppered with sharp thorns originally from east Asia, coils around itself like barbed wire and crowds out other plants. Removing it is made more difficult by the fact that it’s tough to distinguish from plants like black raspberry.

“There’s a lot of ways that organisms compete to survive,” Campbell said. “Invasive species can use a lot of different methods: They could be fast-growing and produce a lot of seeds like garlic mustard, or be like buckthorn, which can produce a chemical that inhibits the growth of other plants.”

Ecologists can measure the extent of an invasive plant’s spread by looking at the percent cover — a rough measure of how much of the area is taken up by the invasive species. Reducing cover from invasive species can be done through precision means, such as targeting individual plants, or the use of controlled fires.

Previously, before conservation efforts took root at Fermilab, invasive species could be found across the lab. Their presence could crowd out smaller plants, like wildflowers. But thanks to efforts from volunteers, visiting students and Fermilab’s Roads and Grounds Crew, the spread of invasive species has been pushed back.

Now, the native wildflowers bloom every year.