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Posts Tagged ‘Cosmic Frontier’


Entrance to Soudan Mine. Credit: Fermilab

It looks like good news for the MINOS and CDMS experiments. The Minneapolis Star Tribune reported today that the fire has been contained in the Soudan Mine, which houses the two  experiments.

The newspaper reported:”Workers also determined there probably has been no water damage to a $100 million University of Minnesota research lab at the bottom of the mine, 2,341 feet below the Earth’s surface, said Minnesota DNR spokesman Mark Wurdeman.”

A three-man crew that entered the mine Sunday did not report seeing any active fire, but officials are holding off calling the fire extinguished until further investigation. The cause of the fire remains undetermined but it appears to have been fed by wooden support timbers inside the former iron ore mine.

The fire was noticed Thursday night when smoke alarms went off. No one was in the mine at the time. It appears from a Minnesota Department of Natural Resources press release Friday that the fire began on the tourist area of the mine, two to four  floors above the experiment halls. The Minnesota Department of Natural Resources operates the mine while the University of Minnesota overseas the high-energy physics laboratory. 

The University is working with firefighters to determine the amount of water that can be sprayed in the mine without causing seepage into the experiment halls. Firefighters also are using flame-suppression foam. The mine has a ventilation system that hopefully should keep smoke out of the delicate detectors.

The MINOS experiment studies how neutrinos change from one type to another over long distances. The detector on the 27th floor of the mine records neutrinos sent via a particle beam from Fermilab 450 miles away. CDMS is a dark matter search using cryogenic germanium and silicon detectors to record dark matter particles that pass from the atmosphere through the earth. 

CDMS inside Soudan Mine. Credit: Fermilab

MINOS detector inside Soudan Mine. Credit: Fermilab

Related information:

Take a virtual tour of the Soudan mine.

 — Tona Kunz


Hugh Lippincott installs a COUPP bubble chamber.

In keeping with the introductory series of posts you’ve seen in this blog from Fermilab experiments, I guess I’ll introduce myself as well. My name is Hugh Lippincott. I’m a postdoc at Fermilab, where I work on an experiment looking for dark matter called COUPP (the experiment is COUPP, not the dark matter. The dark matter is WIMPs, or weakly interacting massive particles).

If you’ve been reading these posts, you’ll know by now that all experiments and many physics concepts have some kind of acronym or cute name, and ours is no different. The acronym stands for Chicagoland Observatory for Underground Particle Physics, but no one thinks of it like that, it’s just COUPP. The real debate is whether the two Ps are silent or not, and we’ve been known to have long debates inside the collaboration about this. I tend to think of it as silent, the way the P sounds when you say coup,  as in overthrowing the state. But if you prefer to think of sounding more like the P in coupe,  a small car, be my guest. Maybe we can have an Internet poll or something in the future and solve that problem once and for all.

This is not actually my first attempt at blogging (although I really do detest that verb and will try to avoid using it henceforth). I wrote several posts at physicsformom.blogspot.com where I attempted to explain a somewhat significant chunk of dark matter physics in a way that could hold my mother’s attention. In this, as in so many things, I came up a bit short, and I haven’t posted anything there for months, but I actually think the three introductory posts on what dark matter is hold up OK. So, instead of going back over all that here, I’ll risk losing half of my audience by being a lazy scientist and ask you to review those posts if you want more information.

Double click on the above icons to see the bubble chamber in action.

I’ll talk more about COUPP and anything else going on as I continue writing. For now, I’ll just say the COUPP collaboration is building a series of bubble chambers , which essentially means it is  literally watching a jar of fluid waiting for bubbles to appear. For example, the accompanying movie shows a neutron (produced by a neutron source placed near the detector) that has scattered four times in our chamber we’ve recently installed in a deep underground site called SNOLAB in Ontario, Canada). This particular event is pretty recent, from a chamber called COUPP-4 since it has 4 kg of fluid.

As I mentioned here ( I’m referencing myself again), bubble chambers were used in the heyday of particle physics when it seemed like new particles were being discovered and understood every two weeks.  We’re now using the same technology, just in a new way.  A bubble chamber is a jar filled with a superheated liquid, or liquid that is hotter than its boiling point. The liquid wishes it were boiling but can’t because there is nowhere to make a bubble. I’m not sure if that entirely makes sense, so I’ll try again. When you boil a pot of water, you see bubbles form first on the metal of your pot. That’s partly because a bubble needs a place to be born, called a nucleation site. In general, this can be an impurity or a rough surface like the metal of the pot or anywhere where a little pocket of gas can form and then grow. Without these impurities or surfaces, the liquid can’t boil, and instead becomes superheated – a very unstable state where any input at all (such as an interacting dark matter particle) that can nucleate a bubble will cause rapid boiling.

Some of you may be familiar with this phenomenon if you’ve ever tried to boil clean water in a ceramic mug in the microwave. In fact, there was a Mythbusters episode about it and a host of other videos on YouTube. What they show is that superheated water will boil (or explode) very suddenly as soon as anything that can create a bubble touches the water.

In our bubble chambers, the bubble is created by particles interacting in the chamber. For example, in the movie above, a neutron scattered and deposited heat in four places, creating four bubbles. We superheated the fluid, making sure that there was nothing else in there to nucleate bubbles, and then waited until some radioactive particle zipped through. When we saw a bubble, we knew something had interacted in the fluid.  And that’s how a bubble chamber works.

— Hugh Lippincott


Lots of interesting news last week about Fermilab, including the releases of a new version of Scientific Linux and Illinois representatives supporting a reduction in proposed cuts to Fermilab’s budget. Below are three stories I found particularly interesting.  

Science asked Have Physicists Already Glimpsed Dark Matter?  Fermilab theorist Dan Hooper thinks so and argues a new look at data from the experiments DAMA, CoGeNT, XENON100 and CDMSII bear him out. But spokespersons for those experiments disagree.

What do you think?

New Scientist published an article by Fermilab Director Pier Oddone about how the closure of the Tevatron later this year won’t put an end to the great scientific results coming out of its detector collaborations, CDF and DZero.  More than 10 petabytes of Tevatron data will provide scientists with plenty of data to sift through for several years

“During that time new ideas and better tools will be developed to squeeze ever more information out of the data,” says Oddone. “This will allow us to continue chasing down the hints of new physics we already see in our analyses.”

Oddone put pen to paper again, this time with the help of Argonne Director Eric Isaacs, to outline effects of proposed science budget cuts on the two labs and beyond in a Chicago Tribune op-ed piece.

    High-tech jobs are just the first casualty of such cuts. Rolling back funding for basic science would dim our nation’s spirit of discovery and entrepreneurship. It would curtail research into how our world works — research that spurs new theories and technologies. And the cuts would be felt across Chicago’s wider high-tech community, which depends on collaboration, new ventures and a workforce trained at some of the world’s most sophisticated facilities.
— Tona Kunz

As the time for our camera’s first light approaches, workload and excitement increase exponentially among the Dark Energy Survey collaborators and it is about time we start sharing the latter. Beginning today, you will find here at Quantum Diaries an insider’s account of our fast progress, frequently updated as we countdown to first light.

So, here we go. If you haven’t heard of us yet, DES is an experiment designed to investigate dark energy, one of the most trending topics of the last 30 years, featured among the top priorities in the world-wide scientific agenda despite a recent funding blow up. DES will image an area of 5,000-square degrees (nearly 1/8 of the sky) using five optical-bands, obtaining detailed measurements of about 300 million galaxies. With this data we can shed light on the mystery of cosmic acceleration by analyzing four complementary probes: supernovae, baryonic acoustic oscillations, galaxy clusters and weak lensing.

DES will use its own powerful new instrument, the Dark Energy Camera, or DECam, which is under construction at  Fermilab.  Building an entirely new system to answer a specific question is a growing trend in astrophysics, probably a consequence of developing close ties with the field of high energy physics.

This 570-megapixel, giant camera is being tested on a telescope simulator (the yellow and red rings that you see in the video) until the end of this month. As a Fermilab postdoc, I am heavily involved in these tests, together with a team that keeps up the fast pace even during the blizzard last week.

Check out this time-lapse video of the DECam construction:

We are now getting ready for a simulated observing run, a comprehensive integration test of the full system. We will use a star projector to simulate the sky and the goal is to take one night’s worth of data. The atmosphere here at the lab is of stress and excitement as this is our last test of the full system before we bring DECam down from the telescope simulator. The results of this test will be very important to guiding us through the next steps.

So here is where we stand nine months before first light. Stay tuned for more updates here or follow us on Facebook. Leave a message in the comments if you want to know more or would like to visit us while the camera is still up on the simulator.

–Marcelle Soares-Santos


Top left image shows SDSS-III's view of a small part of the sky, centered on the galaxy Messier 33. The middle top picture is a zoomed-in image on M33, showing the spiral arms of this galaxy, including the blue knots of intense star formation. The top right-hand image shows a further zoomed-in image of M33 highlighting one of the largest areas of intense star formation in that galaxy. Credit: SDSS

The world’s largest, digital, color image of the night sky became public this month. It provides a stunning image and research fodder for scientists and science enthusiasts, thanks to the Sloan Digital Sky Survey, which has a long connection to Fermilab.

Oh, yeah, and the image is  free.

The image, which would require 500,000 high-definition TVs to view in its full resolution, is comprised of data collected since the start of the survey in 1998.

“This image provides opportunities for many new scientific  discoveries in the years to come,” said Bob Nichol, SDSS-III scientific spokesperson and professor at University of Portsmouth.

Fermilab oversaw all image processing and distribution of data to researchers and the public from 1998 through 2008, for the first seven batches of data. These batches make up a large chunk of the ground-breaking more than a trillion-pixel image. The eighth batch of raw, reduced data, which was released along with the image at the 17th annual meeting of the American Astronomical Society in Seattle was processed by Lawrence Berkley National Laboratory. LBNL, New York University and Johns Hopkins University distributed that data. Fermilab’s SDSS collaboration members now focus solely on analysis.

“This is one of the biggest bounties in the history of science,” said Mike Blanton, professor from New York University and leader of the data archive work in SDSS-III, the third phase of SDSS.  “This data will be a legacy for the ages, as previous ambitious sky surveys like the Palomar Sky Survey of the 1950s are still being used today. We expect the SDSS data to have that sort of shelf life.”

The release expands the sky coverage of SDSS to include a  sizable view of the south galactic pole. Previously, SDSS only imaged small, spread out slivers of the southern sky. Increasing coverage of the southern sky will aid the Dark Energy Survey and the Large Synoptic Survey Telescope both southern sky surveys that Fermilab participates in.

Comparing the two portions of the sky also will help astrophysicists pinpoint any asymmetries in the type or number of large structures, such as galaxies. Cosmic-scale solutions to Albert Einstein’s equations of general
relativity assume that the universe is spherically symmetric, meaning that on a large enough scale, the universe would look the same in every direction.

Finding asymmetry would mean the current understanding of the universe is wrong and turn the study of cosmology on its head, much as the discovery of particles not included in the Standard Model would do for collider physics.

“We would have to rethink our understanding of cosmology,” said Brian Yanny, Fermilab’s lead scientists on SDSS-III. So far the universe seems symmetric.

Whether the SDSS data reveals asymmetry or not it undoubtedly will continue to provide valuable insight into our universe and fascinate amateur astronomers and researchers.

Every year since the start of the survey, at least one paper about the SDSS has made it in the list of the top 10 astronomy papers of the year. More than 200,000 people have classified galaxies from their home computers using SDSS data and projects including Galaxy Zoo and Galaxy Zoo 2.

In the three months leading up to the image’s release a record number of queries, akin to click counts on a Web page,  occurred on the seventh batch of data. During that time, 90 terabytes of pictures and sky catalogues were down loaded by  scientists and the public. That equates to about 150,000 one-hour long CDs.

Scientists will continue to use the old data and produce papers from it for years to come. Early data also works as a check on the new data to make sure camera or processing flaws didn’t produce data anomalies.

“We still see, for instance, data release six gets considerable hits and papers still come out on that in 100s per year,” Yanny said.

So far, SDSS data has been used to discover nearly half a billion astronomical objects, including asteroids, stars, galaxies and distant quasars. This new  eighth batch of data promises even more discoveries.

Fermilab passed the job of data processing and distribution on to others in 2008. The eight batch of data was processed by Lawrence Berkley National Laboratory and distributed by LBNL, New York University and Johns Hopkins University.

Fermilab’s four remaining SDSS collaboration members now focuses solely

illustration of the concept of baryon acoustic oscillations, which are imprinted in the early universe and can still be seen today in galaxy surveys like BOSS. Credit: Chris Blake and Sam Moorfield and SDSS.

on analysis. They are expected to produce a couple dozen papers during the next few years. The group touches on all of SDSS-III’s four sky surveys but focus mainly on the Baryon Oscillation Spectroscopic Survey, or BOSS, which will map the 3-D distribution of 1.5 million luminous red galaxies.

“BOSS is closest to our scientists’ interests because its science goals are to understand dark energy and dark matter and the evolution of the universe,” Yanny said.

For more information see the following:

* Larger images of the SDSS maps in the northern and southern galactic hemispheres are available here and here.

*Sloan’s YouTube channel provides a 3-D visualization of the universe.

*Technical journal papers describing DR8
and the SDSS-III project can be found on the arXiv e-Print server.

*EarthSky has a good explanation of what the colors in the images represent and how SDSS part of an on-going tradition of sky surveys.

*The Guardian newspaper has a nice article explaining all the detail that can be seen in the image.

— Tona Kunz


 To celebrate its 30th anniversary, Discover magazine created a list of the The 12 Most Important Trends in Science Over the Past 30 Years. High-energy particle physics and Fermilab played a part in three of these 12 game-changing research break throughs. Here’s a look at these Discover-selected trends and Fermilab’s contributions to them.

 Trend: The Web Takes Over

Pictured is Fermilab's 2001 home page, which was designed in 1996. Twenty years ago, Fermilab helped to pioneer the URL. It launched one of the first Web sites in the country in 1992. Credit: Fermilab

The first concept for what would become the World Wide Web was proposed by a high-energy particle physicist in 1989 to help physicists on international collaborations share large amounts of data. The first WWW system was created for high-energy physicists in 1991 under the guidance of CERN. 

A year later, Fermilab became the second institution in the United States to launch a website. It also helped initiate the switch easy-to-remember domain name addresses rather than Internet Protocol addresses, which are a string of numbers. This switch helped spur the growth of the Internet and WWW.

Particle physics also secured a place in sports history through its computing savvy. A softball club at CERN, composed of mostly visiting European and American physicists, many connected to Fermilab, was the first ball club in the world to have a page on the World Wide Web, beating out any team from Major League Baseball.

Trend: Universe on a Scale

The field of cosmology has advanced and created a more precise understanding of the evolution and nature of the universe. This has brought high-energy particle physics, cosmology and astronomy closer together. They have begun to overlap in the key areas of dark energy, dark matter and the evolution of the universe.  Discover magazine cites as being particularly noteworthy in these areas the first precise measurement of cosmic microwave background, or CMB, radiation left over from the Big Bang and the discovery with the aid of supernovas that the  expansion of the universe is accelerating.

Dark Energy Camera under construction at Fermilab. Credit: Fermilab

Fermilab physicists study the CMB with the Q/A Imaging Experiment, or QUIET. They study dark energy with several experiments, most notably the long-running Sloan Digital Sky Survey , the Dark Energy Survey, which will be operational at the end of the year, and the Large Synoptic Survey Telescope, potentially operating at the end of the decade or mid-next decade.  

Trend: Physics Seeks the One

During the last few decades the particle physics community has sought to build a mammoth international machine that can probe the tiniest particles of matter not seen in nature since just after the time of the Big Bang.

Initially, this machine was planned for the United States and named the Superconducting Super Collider. Scientists and engineers from Fermilab help with the design and science suite of experiments for the SSC, which was under construction in Texas until it was canceled in 1993.

A similar machine, the Large Hadron Collider in Switzerland, did take shape, starting operation in 2008. Fermilab played a key role in the design, construction and R&D of the accelerator with expertise garnered through the Tevatron accelerator construction, cutting-edge superconducting magnet technology and project managers.

The U.S. CMS remote operation center at Fermilab. Credit: Fermilab

Fermilab now serves as a remote operation center for CMS, one of the two largest experiments at the LHC. Many physicists work on CMS as well as one of the Tevatron’s detector teams, DZero and CDF.  The United States has the largest national contingent within CMS, accounting for more than 900 physicists in the 3,600-member collaboration.

 Fermilab’s computing division serves as one of two “Tier-1” computing distributions centers in the United States for LHC data. In this capacity, Fermilab provides storage and processing capacity for data collected at the LHC that is analyzed by physicists at Fermilab and sent to U.S. universities for analysis there.

Discover magazine cited as a goal of the LHC the search for the Higgs boson, a theorized particle thought to endow other particles with mass, which allows gravity to act upon them so they can form together to create everything in the visible world, such as people, planets and plants. The LHC and the Tevatron are racing to find the Higgs first. The Tevatron has an advantage searching in the lower mass range and the LHC in the higher mass range. Theorists suspect the Higgs lives in the lower mass range. So far, the Tevatron has greatly narrowed the possible hiding places for the Higgs in this range.

— Tona Kunz