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Posts Tagged ‘Argonne National Laboratory’

This article appeared in Fermilab Today on July 24, 2015.

Argonne National Laboratory was attracted to the expertise of this Fermilab magnet team. The team recently developed a pre-prototype magnet for Argonne's APS Upgrade Project. Photo: Doug Howard, Fermilab

Argonne National Laboratory was attracted to the expertise of this Fermilab magnet team. The team recently developed a pre-prototype magnet for Argonne’s APS Upgrade Project. Photo: Doug Howard, Fermilab

A magnet two meters long sits in the Experiment Assembly Area of the Advanced Photon Source at Argonne National Laboratory. The magnet, built by Fermilab’s Technical Division, is fire engine red and has on its back a copper coil that doesn’t quite reach from one end to the other. An opening on one end of the magnet’s steel casing gives it the appearance of a rectangular alligator with its mouth slightly ajar.

“It’s a very pretty magnet,” said Argonne’s Glenn Decker, associate project manager for the accelerator. “It’s simple and it’s easy to understand conceptually. It’s been a very big first step in the APS Upgrade.”

The APS is a synchrotron light source that accelerates electrons nearly to the speed of light and then uses magnets to steer them around a circular storage ring the size of a major-league baseball stadium. As the electrons bend, they release energy in the form of synchrotron radiation — light that spans the energy range from visible to x-rays. This radiation can be used for a number of applications, such as microscopy and spectroscopy.

In 2013, the federal Basic Energy Sciences Advisory Committee, which advises the Director of the Department of Energy’s Office of Science, recommended a more ambitious approach to upgrades of U.S. light sources. The APS Upgrade will create a world-leading facility by using new state-of-the-art magnets to tighten the focus of the APS electron beam and dramatically increase the brightness of its X-rays, expanding its experimental capabilities by orders of magnitude.

Instead of the APS’ present magnet configuration, which uses two bending magnets in each of 40 identical sectors, the upgraded ring will deploy seven bending magnets per sector to produce a brighter, highly focused beam.

Because the APS Upgrade requires hundreds of magnets — many of them quite unusual — Argonne called on experts at Fermilab and Brookhaven National Laboratory for assistance in magnet design and development.

Fermilab took on the task of designing, building and testing a pre-prototype for a groundbreaking M1 magnet — the first in the string of bending magnets that makes up the new APS arrangement.

“At Fermilab we have the whole cycle,” said Fermilab’s Vladimir Kashikhin, who is in charge of magnet designs and simulations. “Because of our experience in magnet technology and the people who can simulate and fabricate magnets and make magnetic measurements, we are capable of making any type of accelerator magnet.”

The M1’s magnetic field is strong at one end and tapers off at the other end, reducing the impact of processes that increase the beam size, producing a brighter beam. Because of this change in field, this magnet is different from anything Fermilab had ever built. But by May, Fermilab’s team had completed and tested the magnet and shipped it to Argonne, where it charged triumphantly through a series of tests.

“The magnetic field shape they were asking for was a little bit challenging,” said Dave Harding, the principal investigator leading the project at Fermilab. “Getting the shape of the steel to produce that distribution and magnetic field required some tinkering. But we did it.”

Although this pre-prototype magnet is unlikely to be installed in the complete storage ring, scientists working in this collaboration view the M1 development as an opportunity to learn about technical difficulties, validate their designs and strengthen their skills.

“Getting our hands on some real hardware injected a dose of reality into our process,” Decker said. “We’re going to take the lessons we learned from this M1 magnet and fold them into the next iteration of the magnet. We’re looking forward to a continuing collaboration with Fermilab’s Technical Division on magnetic measurements and refinement of our magnet designs, working toward the next world-leading hard X-ray synchrotron light source.”

Ali Sundermier

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This article appeared in symmetry on Nov. 12, 2013.

Late last week, the SeaQuest experiment began exploring the structure of protons and the behavior of the particles of which they're made. Photo: Sarah Witman, Fermilab

Late last week, the SeaQuest experiment began exploring the structure of protons and the behavior of the particles of which they’re made. Photo: Sarah Witman, Fermilab

Scientists interested in protons and the sea of particles that compose them are in good spirits this week. Researchers from 15 different institutions that participate in the SeaQuest experiment are watching beam flow into their experiment and data flow out.

The SeaQuest experiment, based at Fermilab and managed by a group of scientists from Argonne laboratory, studies the structure of protons and the behavior of the particles of which they’re made.

Protons contain a constantly simmering sea of particles bound together by the aptly named strong force, which is the strongest of the four fundamental interactions of nature—above the weak force, electromagnetism and gravity.

In the experiment, a particle accelerator sends a beam of protons at very high speeds into a target made of either liquid hydrogen or deuterium or solid carbon, iron or tungsten. These bursts of beam come once a minute and each last about 5 seconds.

This causes protons to essentially break apart and release the quarks and antiquarks within. (Antiquarks are the antiparticle of quarks, meaning they have the same mass but opposite charge.)

SeaQuest physicists will then study in great detail the particles that are released during these interactions. Their aim is to resolve questions about the particles that make up the visible mass in our universe.

Initially, experimenters hope to shed light on the internal structure of protons, specifically, the ratio of anti-up quarks to anti-down quarks—two types of antiquarks with different properties.

Results from SeaQuest’s predecessor, NuSea, and DESY’s Hermes experiment, both reported in 1998, found a surprise in measuring the ratio of anti-down quarks to anti-up quarks in the proton; it trended toward a value of less than one. This shook up current assumptions about symmetry between these particles and might hint that we have an incomplete understanding of the strong force.

SeaQuest is re-examining this notion, using beam with about one-eighth of the energy and 50 times the luminosity of that of NuSea.

“We think in several months we will have enough data to confirm what NuSea saw,” says Argonne physicist Paul Reimer, spokesperson for SeaQuest. “Then we of course want to do better, which will take a year or more after that.”

The experiment is also intended to study how exactly the strong force binds these subnuclear particles together and how those effects are modified when the proton is inside an atom’s nucleus rather than isolated and separated from it. Quarks’ angular momentum, also called their “spin,” is known to be distributed differently depending on if the proton is “free” or if it is bound inside a nucleus at the time.

Yet another goal of the experiment is to measure how much energy quarks lose as they pass through cold nuclear matter. Both of these pursuits will be explored simultaneously.

The last time SeaQuest saw beam, during a commissioning run, it lasted about six weeks, from March 8 to the end of April 2012. The data from that run, Reimer says, was useful for debugging the detector and hammering out the algorithms they need to take data this time around.

Over the past year and a half, while beam was shut down for scheduled upgrades, SeaQuest researchers and technicians used that downtime to make technical improvements to the experiment’s spectrometer (pictured above) to enable higher beam quality and smoother delivery of protons, which should result in greater accuracy.

University of Michigan postdoc Josh Rubin says the detector and experiment are ready to take on the mysteries of the proton.

“We are all excited at the chance to study the sea of quarks,” he says.

Sarah Witman

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httpv://www.youtube.com/watch?v=YtuMqjCiymQ&list=UUD5B6VoXv41fJ-IW8Wrhz9A&index=3&feature=plcp

It could be the largest structure ever to be built from plastic. Its footprint of 1,052 square meters will cover an area about the size of a quarter of a football field. Its height will rise past the top of a five-story apartment building. And with 368,640 tubes of white PVC, the structure will have about as many components as some of the largest LEGO structures built in the world.

The NOvA detector will comprise 368,640 PVC tubes that will be filled with mineral oil. A company in Wisconsin extrudes the tubes, which look like extra-long downspouts, in panels of 16. Credit: Rich Talaga, Argonne

But this huge structure, to be constructed in Ash River, Minn., won’t serve as a plastic replica. It will be the skeleton of a fully functional particle detector. Wired with fiber optic cables and filled with 500 truckloads of mineral oil, the 15,000-ton NOvA detector will enable scientists to discover how the masses of the three types of neutrinos—the lightest, tiniest particles known to mankind—stack up.

Last week, the preparations for the assembly of this white PVC behemoth passed a pivotal test. In an assembly building at Fermilab, 40 miles west of Chicago, scientists, engineers and technicians from Fermilab, Argonne National Laboratory and the University of Minnesota successfully operated for the first time the NOvA pivoter, the hydraulic system developed by Fermilab to move and rotate huge, 200-ton plastic blocks for the assembly of the NOvA detector. (See this 3-minute video with a time lapse of the pivoter test and a fly-through animation of the NOvA detector hall.)

“This is a big deal,” said Fermilab physicist Pat Lukens, who manages the assembly of the detector. “Now the focus will shift to Ash River. We will assemble 500 truckloads of plastic modules.”

But this is no ordinary plastic. Argonne’s Rich Talaga and other NOvA collaborators spent many years finding the right ingredients to produce the strongest and most reflective PVC for the 16-meter-long tubes that hold and support the weight of the mineral oil.

“Ordinary plastic tends to deform under pressure,” said Talaga, who worked closely with Fermilab’s Anna Pla-Dalmau. “Think of a plastic coat hanger. It changes shape when you put a sweater on it. We had to find a plastic that has to be strong for 20 years and doesn’t get weaker and rupture.”

Using a machine developed and tested at Argonne National Laboratory, technicians apply special no-drip glue to a NOvA panel to create blocks that are 16 meters by 16 meters square and weigh 200 tons. Credit: Rich Talaga, Argonne

For Extrutech Plastics in Manitowoc, Wisc., a company that makes PVC wall and ceiling panels and other plastic products, the purchase order for the NOvA tubes was the largest ever. The company has begun the production of the PVC panels, which look like 16 extra-long downspouts with a four-by-six-centimeter cross section attached side-by-side. The panels, which must meet the tight specifications for the thickness and uniformity of the NOvA plastic, are shipped to a warehouse rented by the University of Minnesota. There, students and technicians outfit each tube with a fiber optic cable that will capture the faint light that a neutrino creates when it breaks up an atom in the mineral oil. Avalanche photodiodes attached to each fiber will record and amplify the signal, which is then digitized and transmitted to the central data acquisition system.

To make sure that no light gets lost, Talaga and his group used a special PVC formulation that includes large amounts of titanium-dioxide to create a strong plastic that is white and highly reflective.

“The oil doesn’t absorb much light,” said Talaga. “The light created by a neutrino interaction is either absorbed by the walls of the tubes or by the fiber optic cable inside each tube. By making the walls highly reflective, the light bounces back eight, nine or ten times without significant absorption and you see a stronger signal in the fiber.”

To transform the roughly 24,000 plastic panels into one giant particle detector, technicians will place 24 panels next to each other to make a layer of tubes, 16 meters by 16 meters square. After an application of special no-drip glue, the next layer will be placed on top, with the tubes lying perpendicularly to the layer below. Gluing and lifting of the 1,000-pound panels will be done with machines developed and tested at Argonne, where the first set of machines was used to build the test block used on the pivoter at Fermilab.

The Argonne group just finished the installation of the first gluing machine at Ash River. The full-size pivoter, six times as wide as the one tested at Fermilab, is under construction and will be ready for operation early next year. Bill Miller, of the University of Minnesota, who participated in the pivoter test at Fermilab, will lead the assembly of the detector in Ash River. He will supervise local staff, hired by the University of Minnesota for the task.

“We plan to assemble the first block in Ash River this spring,” said Lukens, who’s overseen the development of the NOvA assembly plans for three years. “It will take 18 months to assemble the entire detector.”

Scientists from 28 institutions are working on the NOvA experiment. When operational, the experiment will examine the world’s highest-intensity, longest-distance neutrino beam, generated at the Fermilab.

Engineers at Fermilab designed and tested a hydraulic system that will move and rotate the huge, 200-ton plastic blocks for the assembly of the NOvA detector. Credit: Reidar Hahn, Fermilab

Accelerators will produce a beam of muon neutrinos that will travel straight through the earth to the NOvA detector in northern Minnesota. During their split-second trip to Ash River, some of these neutrinos will turn into electron neutrinos and tau neutrinos. By measuring the composition of the neutrino beam with a small, 222-ton detector at Fermilab and a large detector in Ash River, scientists expect to discover the neutrino mass hierarchy, determining whether there are two light neutrinos and one heavy one, or two heavy ones and a light one.

For photos of the construction of the NOvA detector building in Ash River, see the photo gallery in the October 2011 issue of symmetry magazine.

— Kurt Riesselmann

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