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Posts Tagged ‘RHIC’

This post was written by Brookhaven Lab scientists Shigeki Misawa and Ofer Rind.

Run 13 at the Relativistic Heavy Ion Collider (RHIC) began one month ago today, and the first particles collided in the STAR and PHENIX detectors nearly two weeks ago. As of late this past Saturday evening, preparations are complete and polarized protons are colliding with the machine and detectors operating in “physics mode,” which means gigabytes of data are pouring into the RHIC & ATLAS Computing Facility (RACF) every few seconds.

Today, we store data and provide the computing power for about 2,500 RHIC scientists here at Brookhaven Lab and institutions around the world. Approximately 30 people work at the RACF, which is located about one mile south of RHIC and connected to both the Physics and Information Technology Division buildings on site. There are four main parts to the RACF: computers that crunch the data, online storage containing data ready for further analysis, tape storage containing archived data from collisions past, and the network glue that holds it all together. Computing resources at the RACF are split about equally between the RHIC collaborations and the ATLAS experiment running at the Large Hadron Collider in Europe.

Shigeki Misawa (left) and Ofer Rind at the RHIC & ATLAS Computing Facility (RACF) at Brookhaven Lab

Where Does the Data Come From?

For RHIC, the data comes from heavy ions or polarized protons that smash into each other inside PHENIX and STAR. These detectors catch the subatomic particles that emerge from the collisions to capture information—particle species, trajectories, momenta, etc.—in the form of electrical signals. Most signals aren’t relevant to what physicists are looking for, so only the signals that trip predetermined triggers are recorded. For example, with the main focus for Run 13 being the proton’s “missing” spin, physicists are particularly interested in finding decay electrons from particles called W bosons, because these can be used as probes to quantify spin contributions from a proton’s antiquarks and different “flavors” of quarks.

Computers in the “counting houses” at STAR and PHENIX package the raw data collected from selected electrical signals and send it all to the RACF via dedicated fiber-optic cables. The RACF then archives the data and makes it available to experimenters running analysis jobs on any of our 20,000 computing cores.

Recent Upgrades at the RACF

Polarized protons are far smaller than heavy ions, so they produce considerably less data when they collide, but even still, when we talk about data at the RACF, we’re talking about a lot of data. During Run 12 last year, we began using a new tape library to increase storage capacity by 25 percent for a total of 40 petabytes—the equivalent of 655,360 of the largest iPhones available today. We also more than doubled our ability to archive data for STAR last year (in order to meet the needs of a data acquisition upgrade) so we can now sustain 700 megabytes of incoming data every second for both PHENIX and STAR. Part of this is due to new fiber-optic cables connecting the counting houses to the RACF, which provide both increased data rates and redundancy.

With all this in place, along with those 20,000 processing cores (most computers today have two or four cores), certain operations that used to require six months of computer time now can be completed often in less than one week.

Looking Ahead

If pending budgets allow for the full 15-week run planned, we expect to collect approximately four petabytes of data from this run alone. During the run, we meet formally with liaisons from the PHENIX and STAR collaborations each week to discuss the amount of data expected in the coming weeks and to assess their operational needs. Beyond these meetings, we are in continual communication with our users, as we monitor and improve system functionality, troubleshoot, and provide first-line user support.

We’ll also continue to work with experimenters to evaluate computing trends, plan for future upgrades, and test the latest equipment—all in an effort to minimize bottlenecks that slow the data from getting to users and to get the most bang for the buck.

— Shigeki Misawa – Group Leader, RACF Mass Storage and General Services

— Ofer Rind – Technology Architect, RACF Storage Management

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Heat: Adventures in the World's Fiery Places (Little Brown, 2013). If you haven't already fallen in love with the groundbreaking science that's taking place at RHIC, this book about all things hot is sure to ignite your passion.

Bill Streever, a biologist and best-selling author of Cold: Adventures in the World’s Frozen Places, has just published his second scientific survey, which takes place at the opposite end of the temperature spectrum. Heat: Adventures in the World’s Fiery Places features flames, firewalking, and notably, a journey into the heart of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory.

I accompanied Streever for a full-day visit in July 2011 with physicist Barbara Jacak of Stony Brook University, then spokesperson of the PHENIX Collaboration at RHIC. The intrepid reporter (who’d already tagged along with woodland firefighters and walked across newly formed, still-hot volcanic lava—among other adventures described in the book) met with RHIC physicists at STAR and PHENIX, descended into the accelerator tunnel, and toured the refrigeration system that keeps RHIC’s magnets supercold. He also interviewed staff at the RHIC/ATLAS Computing Facility—who face the challenge of dissipating unwanted heat while accumulating and processing reams of RHIC data—as well as theorists and even climate scientists, all in a quest for understanding the ultrawarm.

The result is an enormously engaging, entertaining, and informative portrayal of heat in a wide range of settings, including the 7-trillion-degree “perfect” liquid quark-gluon plasma created at RHIC, and physicists’ pursuit of new knowledge about the fundamental forces and interactions of matter. But Streever’s book does more: It presents the compelling story of creating and measuring the world’s hottest temperature within the broader context of the Lab’s history, including its role as an induction center during both World Wars, and the breadth and depth of our current research—from atoms to energy and climate research, and even the Long Island Solar Farm.

“Brookhaven has become an IQ magnet, where smart people congregate to work on things that excite geniuses,” he writes.

Streever’s own passion for science comes across clearly throughout the book. But being at “the top of the thermometer” (the title of his final chapter, dedicated in part to describing RHIC) has its privileges. RHIC’s innermost beam pipes—at the hearts of its detectors, inside which head-on ion collisions create the highest temperature ever measured in a laboratory—have clearly left an impression:

“… I am forever enthralled by Brookhaven’s pipes. At the top of the thermometer, beyond any temperature that I could possibly imagine, those pipes explore conditions near the beginning of the universe … In my day-to-day life, bundled in a thick coat or standing before my woodstove or moving along a snow-covered trail, I find myself thinking of those pipes. And when I think of them, I remember that at the top of the thermometer lies matter with the audacity to behave as though it were absolutely cold, flowing like a perfect liquid…”

There’s more, a wonderful bit more that conveys the pure essence of science. But I don’t want to spoil it. Please read and share this book. The final word is awe.

The book is available for purchase through major online retailers and in stores.

-Karen McNulty Walsh, BNL Media & Communications Office

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Theoretical physicist Raju Venugopalan

We sat down with Brookhaven theoretical physicist Raju Venugopalan for a conversation about “color glass condensate” and the structure of visible matter in the universe.

Q. We’ve heard a lot recently about a “new form of matter” possibly seen at the Large Hadron Collider (LHC) in Europe — a state of saturated gluons called “color glass condensate.” Brookhaven Lab, and you in particular, have a long history with this idea. Can you tell me a bit about that history?

A. The idea for the color glass condensate arose to help us understand heavy ion collisions at our own collider here at Brookhaven, the Relativistic Heavy Ion Collider (RHIC)—even before RHIC turned on in 2000, and long before the LHC was built. These machines are designed to look at the most fundamental constituents of matter and the forces through which they interact—the same kinds of studies that a century ago led to huge advances in our understanding of electrons and magnetism. Only now instead of studying the behavior of the electrons that surround atomic nuclei, we are probing the subatomic particles that make up the nuclei themselves, and studying how they interact via nature’s strongest force to “give shape” to the universe today.

We do that by colliding nuclei at very high energies to recreate the conditions of the early universe so we can study these particles and their interactions under the most extreme conditions. But when you collide two nuclei and produce matter at RHIC, and also at the LHC, you have to think about the matter that makes up the nuclei you are colliding. What is the structure of nuclei before they collide?

We all know the nuclei are made of protons and neutrons, and those are each made of quarks and gluons. There were hints in data from the HERA collider in Germany and other experiments that the number of gluons increases dramatically as you accelerate particles to high energy. Nuclear physics theorists predicted that the ions accelerated to near the speed of light at RHIC (and later at LHC) would reach an upper limit of gluon concentration—a state of gluon saturation we call color glass condensate.* The collision of these super-dense gluon force fields is what produces the matter at RHIC, so learning more about this state would help us understand how the matter is created in the collisions. The theory we developed to describe the color glass condensate also allowed us to make calculations and predictions we could test with experiments. (more…)

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The Glue that Binds Us All

Wednesday, June 13th, 2012

RHIC, the Relativistic Heavy Ion Collider at Brookhaven Lab, found it first: a “perfect” liquid of strongly interacting quarks and gluons – a quark-gluon plasma (QGP) – produced by slamming heavy ions together at close to the speed of light. The fact that the QGP produced in these particle smashups was a liquid and not the expected gas, and that it flowed like a nearly frictionless fluid, took the physics world by surprise. These findings, now confirmed by heavy-ion experiments at the Large Hadron Collider (LHC) in Europe, have raised compelling new questions about the nature of matter and the strong force that holds the visible universe together.

Similarly, searches for the source of “missing” proton spin at RHIC have opened a deeper mystery: So far, it’s nowhere to be found.

To probe these and other puzzles, nuclear physicists would like to build a new machine: an electron-ion collider (EIC) designed to shine a very bright “light” on both protons and heavy ions to reveal their inner secrets. (more…)

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On May 26, 2005, a new supercomputer, a pioneering giant of its time, was unveiled at Brookhaven National Laboratory at a dedication ceremony attended by physicists from around the world. That supercomputer was called QCDOC, for quantum chromodynamics (QCD) on a chip, capable of handling the complex calculations of QCD, the theory that describes the nature and interactions of the basic building blocks of the universe. Now, after a career of state-of-the-art physics calculations, QCDOC has been retired — and will soon be replaced by a new “next generation” machine. (more…)

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Dave Mosher (left) and Kendra Snyder inside the STAR detector at Brookhaven's Relativistic Heavy Ion Collider, minutes after getting engaged. (photo courtesy of Dave Mosher/davemosher.com)

When Kendra Snyder, a science writer in Brookhaven Lab’s Media & Communications Office, entered the STAR detector at the Relativistic Heavy Ion Collider (RHIC) last Friday afternoon to view some unusual crystalline deposits — supposedly formed in the beam pipe — she got an even bigger surprise: a diamond ring and a marriage proposal from fellow science writer Dave Mosher.

The unusual proposal, dubbed “The Nerdiest Marriage Proposal . . . Ever” on Mosher’s blog, triggered the interest of a reporter at The Daily, News Corporation’s new iPad-only daily newspaper. Snyder and Mosher were interviewed last night, and the story — which includes references to RHIC’s near-light-speed gold ion collisions — appears in today’s edition.

Even if you don’t have an iPad, you can view the video, “Geek Love,” here.

– Karen McNulty Walsh, Brookhaven Media & Communications

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Pumping Up Proton Polarization

Thursday, April 7th, 2011

Brookhaven Lab’s oldest and most-trophied workhorse, the Alternating Gradient Synchrotron (AGS), has broke its own world record for producing intense beams of polarized protons – particles that “spin” in the same direction.

Spin, a quantum property that describes a particle’s intrinsic angular momentum,  is used in a wide range of fields, from astronomy to medical imaging. But where spin comes from is still unknown.

In this picture of a proton-proton collision, the spin of the particles is shown as arrows circling the spherical particles. The red and green particles represent reaction products from the collision that are "seen" and analyzed by RHIC detectors.

To explore the mystery of spin, Brookhaven’s Relativistic Heavy Ion Collider (RHIC) smashes beams of polarized protons at close to the speed of light. RHIC is the only machine in the world with this capability. But before reaching RHIC’s high-speed collision course, the protons travel about one million miles through a series of linear and circular accelerators, including the AGS, a 41-year old circular accelerator more than a half mile around. Home to three of BNL’s seven Nobel Prize-winning discoveries, the AGS is Brookhaven’s longest-running accelerator.

Now, with a new upgrade, the AGS can keep up to 75 percent of those particles in the beam polarized while they accelerate – a 5 to 8 percent increase over the previous record. This feat was accomplished with custom-built power supplies created from old inventory and two revamped 1960s quadrupole magnets pulled from storage.

The two refurbished quadrupole magnets before being installed at the AGS

As the particles race through the AGS, two of the customized power supplies quickly pulse, hold, and pull back surges of power for each of the quadrupoles in a matter of milliseconds. Forty-two times within half a second, these pulsed currents produce magnetic kicks that keep the particles spinning in the correct direction.

For more details, see this story.

-Kendra Snyder, BNL Media & Communications

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Going in Circles

Wednesday, February 23rd, 2011

RHIC's main control room

If you were expecting this blog entry to be about the great song from the Friends of Distinction, it unfortunately won’t be the case. Instead, I’m taking you on the first trip this year of RHIC’s Yellow beam, one of two oppositely circulating particle beams that collide in the center of RHIC’s detectors. Why? Because the main goal of my first shift of Run11 was to get our particles to circulate in a closed orbit in the Yellow beamline. This will also give me the opportunity to get back to some of the technical terms I used in my previous post. So allow me to go over a little bit of accelerator physics theory for a minute.

RHIC, which stands for Relativistic Heavy Ion Collider, is the name given to the large circular collider at Brookhaven National Laboratory; in order for particles to actually reach the collider from their source, they need travel through a series of other accelerators:

  1. the LINAC for protons, the Tandem-to-Booster beamline for heavy ions
  2. the Booster synchrotron
  3. the Booster-to-AGS (BtA) line
  4. the Alternating Gradient Synchrotron (AGS)
  5. the AGS-to-RHIC (AtR) line

(more…)

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Quark Matter game cards

Want to “play” with subatomic particles? You could work at Brookhaven Lab’s Relativistic Heavy Ion Collider (RHIC) or the LHC — or you could play a new card game invented by a group of Hungarian students and RHIC/PHENIX collaborator Tamás Csörgő.

The students — Csaba Török and his friend Judit Csörgő (Tamás’ daughter) — invented the game as an entertaining way to learn about subatomic particles and their interactions, inspired by physics presentations in the science club at their secondary school, where Tamás was a frequent presenter.

The game, now available for purchase in both Hungarian and English, “provides a great opportunity for all people — not just physicists — to get acquainted with some of the elementary particles and concepts of the Standard Model,” said Csaba.

The deck consists of cards that represent particles and anti-particles from neutrinos, to electrons, positrons, muons, and quarks, which can be used for four different games. In “Quark Matter,” a game that models RHIC physics, the cards are mixed face up on a table, packed closely together to represent matter at the instant of collision — a quark-gluon plasma (QGP). The object for each player is to quickly extract particles as they would emerge from the collision, in order: non-interacting neutrinos and antineutrinos first, followed by electron/positron and muon/anti-muon pairs, and then quarks and anti-quarks as they hadronize, or freeze out, to form mesons, baryons, and anti-baryons — all while maintaining a neutral color charge.

Brookhaven's Educational Programs staff introduced the card game to students at Rocky Point Middle School.

As players race to extract cards, the “system” expands just as it does in a real RHIC collision. Players score points for each correct particle pick. More sophisticated players can name the particles as they extract them. Additional games teach and reinforce deeper concepts, such as weak decays and several laws of conservation.

For more information, visit particles card game.

-Karen McNulty Walsh, BNL Media & Communications

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Behind the Scenes: RHIC

Monday, January 10th, 2011

Hello, everyone. I’m Guillaume Robert-Demolaize, an accelerator physicist at Brookhaven National Laboratory, working on the Relativistic Heavy Ion Collider (RHIC). I work as a shift leader on the collider during the beam development period, which means that I have to study the behavior of the particles circulating in our two rings and change some of the machine parameters in order to steer both beams into collision for our two detectors (STAR and PHENIX) to acquire data in the best possible conditions. When RHIC is not running, I participate in the design and setup of some of the tools required to run the machine. I am mainly in charge of the RHIC online model, a server that allows converting the optic functions of the machine into values of current for the power supplies of the RHIC magnets. This might be a lot of technical terms for a simple description of my job; so one of my next posts in this blog will be dedicated to go over these terms in further details.

I was born in 1981 in Aix-en-Provence, in the south of France. I got interested in science as a teenager when the first physics and chemistry classes started, and physics won me over very quickly. I thought it was impressive that I could describe and/or predict how something would move with just a series of equations. By the time I reached 19 and had to select an engineering school, I read an article about SLAC National Accelerator Laboratory and its collider for a school project; I got hooked instantly and never looked back. I then went to the ENSPG, a nuclear energy engineering school in Grenoble, France and graduated in 2003 with a specialization in accelerator physics after an internship at the SOLEIL synchrotron in Paris, France.

(more…)

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