The popular web site Softpedia has written about SMU’s new “world’s fastest integrated circuit” designed for use in the challenging environment of the Large Hadron Collider.
The popular web site Softpedia has written about SMU’s new “world’s fastest integrated circuit” designed for use in the challenging environment of the Large Hadron Collider.
The site, popular for software downloads and science and technology information, noted that the job of the new high-speed integrated circuit was designed for the LHC’s high-radiation environment, as well as for high data bandwidth, low-power dissipation and extremely high reliability. SMU physicist Jingbo Ye, an associate professor of physics, led development of the circuit.
Excerpt: By Tudor Vieru Science Editor
A group of experts from the Southern Methodist University (SMU), in Dallas, announces the development of a new, super-fast circuit designed specifically to augment the capabilities of one of the main particle detectors of the Large Hadron Collider. The LHC is the largest physics experiment ever designed, and its goal is to discover some of the most fundamental knowledge about the Universe and the elementary particles and forces that govern our world.
With the development of the new integrated circuits, called “link-on-chip” or LOC serializer circuits, the team hopes to be able to boost the performances of the LHC’s ATLAS particle detectors, one of the three main instruments in the 27-kilometer-long tunnel of the accelerator. The innovation was designed specifically to be used by the Liquid Argon Calorimeter, an ATLAS sub-detector that could function a lot better, and overall more efficiently, once the new application-specific integrated circuits (ASIC) are added. The SMU team is directly involved in the ATLAS collaboration.
There was a large number of factors researchers at the university needed to consider when creating the LOC. In addition, the large amount of radiation that is produced as the LHC collides beams of protons head-on at the highest energy levels ever achieved, there are also other issues to consider. The calorimeter needs to be able to handle a high data bandwidth, low power dissipation, and must feature an extremely high degree of reliability as well. There is very little room for error in an endeavor such as the LHC, and all of its components need to respect a vast array of norms and rules.
This simulated black hole from ATLAS proton collisions would quickly decay into particle debris. Credit: CERN
A new high-speed integrated circuit to reliably transmit data in the demanding environment of the world’s largest physics experiment is the fastest of its kind.
This new “link-on-chip” — or LOC serializer circuit — was designed by physicists at Southern Methodist University in Dallas as a component for use in a key experiment of the Large Hadron Collider particle accelerator in Europe.
The miniscule SMU LOC serializer was designed for ATLAS, which is the largest particle detector at the Large Hadron Collider.
Jingbo Ye views SMU LOC serializer
The LHC, as it’s called, is a massive, high-tech tunnel about 100 meters underground. Within the LHC’s circular, 17-mile-long tunnel, protons traveling at high energy are smashed together and broken apart so physicists worldwide can analyze the resulting particle shower detailed in a flood of electronic data.
Data holds key to bold new physics discoveries
The data transmits from the LHC via a tiny serializer circuit enabling electronic readouts. Physicists analyze the data to discover answers to unsolved scientific mysteries such as the Big Bang, dark matter, black holes, the nature of the universe and the Higgs particle that gives mass to quarks and electrons. SMU is a member of the ATLAS Experiment.
The LHC is a program of the Geneva-based international scientific consortium known as the European Organization for Nuclear Research, or CERN. In March CERN announced that the LHC had successfully begun colliding protons at an energy three and a half times higher than previously achieved at any particle accelerator.
SMU LOC designers challenged by LHC’s formidable environment
SMU’s new world’s-fastest LOC serializer is what the industry calls an integrated circuit made for a specific use, or “ASIC” for application-specific integrated circuit. It was designed for the LHC’s high-radiation environment, as well as for high data bandwidth, low-power dissipation and extremely high reliability, said physicist Jingbo Ye. An associate professor of physics, Ye led development of SMU’s LOC serializer.
The SMU LOC serializer was perfected over the past three years in the SMU Research Laboratory for Optoelectronics and ASIC Development in the Department of Physics. An added feature of the SMU LOC serializer is that it can operate at cryogenic temperatures and has been tested down to liquid nitrogen temperatures of -346 degrees Fahrenheit.
It was designed to transmit data for the optical link readout system of the ATLAS Liquid Argon Calorimeter, an ATLAS sub-detector that measures the energies of electrons and photons generated at the center of ATLAS where protons collide. Because the electronic readout components are in the center of the ATLAS detector, they are essentially inaccessible for routine maintenance, so reliability is paramount, Ye said.
Serializer transmits data shower from colliding protons
With a data transmission rate of 5.8 billion-bits per second, the SMU LOC serializer represents the first milestone for the SMU-led team. The team plans to develop an even faster ASIC serializer that transmits data at up to 10 billion-bits per second. Faster circuits are critical as CERN continues increasing the LHC’s luminosity, thereby generating more and more data.
“SMU’s LOC serializer is the fastest in our field for the moment,” Ye said. “CERN is developing another fast ASIC serializer that does not yet match our speed. SMU’s next goal is to increase both the data speed and the number of data lanes to produce an even faster LOC serializer. In the next few years, we hope to increase the total speed by a factor of 62 more than what is installed in ATLAS.”
Ye presented the SMU LOC serializer design in February at CERN. Made of complementary metal-oxide-semiconductor transistors in silicon-on-sapphire, the serializer’s design details also will be presented to scientists in April in Hamburg during the ATLAS Upgrade Week at the DESY laboratory, Germany’s premier research center for particle physics. The SMU LOC serializer research was funded by the National Science Foundation and the U.S. Department of Energy.
The existing LOC serializer in use at present in the ATLAS Liquid Argon Calorimeter was previously developed and installed by an SMU-led team of physicists and engineers from France, Sweden, Taiwan and the United States.
Faster serializer a critical component for Super LHC
SMU’s new LOC serializer is critical for the upgrade of the Large Hadron Collider, called the Super LHC, which is planned to go online in 2017, Ye said.
“The original ATLAS design used a commercial serializer that was purchased from Agilent Technologies,” Ye said. “But for the Super LHC there is no commercial device that would meet the requirements, so — being typical physicists — we set out to design it ourselves.”
The ATLAS Liquid Argon Calorimeter’s existing optical link system, delivered by SMU physicists, has a data bandwidth of 2.4 terabits per second over 1,524 fibers, or 1.6 billion bits per second per fiber, more than 1,000 times faster than a T1 line of 1.544 megabits per second. The next generation of this optical link system will be based on the new SMU LOC serializer, and it will reach 152.4 terabits per second for the whole system.
More selectivity with faster data transfer
“Fast information transfer from the detector to the computer processing system is a necessity for handling the significantly increasing amounts of data expected in the next round of LHC experiments,” said Ryszard Stroynowski, U.S. Coordinator for the ATLAS Liquid Argon Calorimeter, and chair and professor of physics at SMU. “It will allow ATLAS to be more selective in the choices of events sent for further analysis.”
A radiation-tolerant, high-speed and low-power LOC serializer is critical for optical link systems in particle physics experiments, Ye said, noting that specialized ASIC devices are now common components of most readout systems.
“The ever increasing complexity of particle physics experiments imposes new and challenging constraints on the electronics,” Ye said. “The LOC serializer was a formidable task, but our team was up to the challenge.” — Margaret Allen
Fredrick Olness, a professor in SMU’s Physics Department, has been named the inaugural lecturer in a program launched by the DESY laboratory, Germany’s premier research center for particle physics.
DESY’s “Theorist of the Week” program will bring prominent theorists from around the globe to spend a week at the lab’s analysis center in Hamburg, Germany. Olness, who will visit the laboratory in March, is the program’s first guest physicist.
Fredrick Olness
The visit is hosted by DESY. The “Theorist of the Week” program is sponsored by the prestigious Helmholtz Alliance, a structured research network comprising 18 German universities and three institutes, as well as DESY.
SMU’s Olness is co-spokesman of the CTEQ collaboration, an international collaboration of 30 experimentalists and theorists from 16 universities and five national labs working on quantum chromodynamics. Known as QCD, quantum chromodynamics is the theory of the strong nuclear force that binds the protons and neutrons inside the atomic nucleus.
At DESY, Olness will present a seminar on his research specialty and also will participate in extended discussions with German experts. This program will improve the exchange between theory and experiment, provide a forum for presenting the latest research advances, and will also generate an active intellectual environment for Ph.D. students.
The Alliance is part of a broad international effort to explore the physics at the Terascale — the highest energy scales available in the laboratory, enabling scientists to study interactions at the smallest distance scales as they try to characterize the fundamental forces and building blocks of nature.
An important component of this Terascale program is the new CERN particle accelerator near Geneva, Switzerland, called the Large Hadron Collider, or LHC. It is the highest-energy particle accelerator ever built. By accelerating protons to nearly the speed of light, the LHC functions as a “high-energy microscope” to study matter at the smallest distance scales.
“With the start-up of CERN’s LHC this past fall, we soon expect revolutionary results that will help us explain the origin of matter and decode the nature of dark matter,” Olness said. “Additionally, these results may provide glimpses of proposed extra spatial dimensions and new particles predicted by grand unified theories. Evidence for any of these phenomena would dramatically change our view of the world.”
Olness will visit DESY from March 8 to 12 and present his recent work on the “benchmark” processes that will be used to calibrate the discoveries that scientists anticipate will be made at CERN’s LHC. For example, Olness’ work on the W and Z boson production at the LHC can be used to calibrate various searches for the important Higgs boson, the hypothesized notion of super symmetry and other “new physics” processes that scientists hope to discover. Olness, with his CTEQ collaborators, will analyze a combination of data from DESY’s HERA electron-proton collider, the Tevatron proton-antiproton collider at the Department of Energy’s Fermi National Accelerator Laboratory near Chicago, Illinois, and various fixed-target experiments to distinguish “new physics” from “old physics” and thereby maximize the discovery potential of the LHC.
Moving an ATLAS end-cap calorimeter, which measures the energy of particles produced close to the axis of the beam when protons collide. Credit: CERN
Stroynowski, Kehoe, Sekula and Ye work on the ATLAS detector, the largest of the four detectors that will study particle collisions at the LHC. Nadolsky is a leading researcher in the area of parton distribution functions, which are an essential component for making accurate predictions for LHC physics.
Olness was elected a Fellow of the American Physical Society in 2005 for significant contributions to understanding nucleon structure and heavy quark production in perturbative quantum chromodynamics. In addition to the DESY laboratory, Olness has worked at DOE’s Fermilab and at CERN’s LHC. Olness is co-author of the textbook Mathematica for Physics, which integrates new computer algebra tools into the core physics curriculum. This text is now in its 2nd Edition and also has been translated into Japanese.
At SMU, Olness received an SMU Ford Fellowship, the SMU “M” Award, and the President’s Associates Outstanding Faculty Award. He is director of the Dallas Regional Science & Engineering Fair, serves as president of the SMU Faculty Senate and brings physics to North Texas students with his “Physics Circus” public lectures to local schools.
“I particularly enjoy bringing my excitement for science discovery into the classroom with the ‘Physics Circus’ demonstration shows,” Olness said. “My love for science was fueled by my curiosity of how things work. Whether we are understanding the physics principles of a bed of nails or the substructure of the atom, curiosity is an essential ingredient for discovery.”
New high-energy particle research by a team working with data from Fermi National Accelerator Laboratory further heightens the uncertainty about the exact nature of a key theoretical component of modern physics — the massive fundamental particle called the Higgs boson.
Analysis of data from particle collisions resulting in two leptons helps improve measurements of the mass of another heavy subatomic particle called the top quark, says physicist Robert Kehoe at SMU, who led the team that calculated the measurement.
Improving the measurement of the mass of the top quark bears on the nature of the Higgs, says Kehoe, an assistant professor in SMU’s Department of Physics.
The Higgs was postulated in the 1960s to help explain how basic elements of the universe fit together and interact. It is responsible for a phenomenon called the Higgs mechanism, which gives mass to the fundamental particles of nature.
Physicists have searched for more than four decades to observe the never-before-seen Higgs. Now they hope it will be observed in the next few years since data started flowing recently from the world’s newest and largest high-energy particle accelerator, the CERN laboratory’s Large Hadron Collider near Geneva, Switzerland.
Physicists theorize that the top quark — because of its sizable mass — is sensitive to the Higgs and therefore may point to it. They theorize that knowing the mass of the top quark narrows the range of where the Higgs will be detected in CERN’s LHC collisions. The top quark is one of 16 species of subatomic particles that physicists have observed. It was predicted in the 1970s and observed in 1995. Increasingly precise measurements of its mass have been achieved almost every year since, and physicists closely watch the incremental measurements of the top quark.
Fermilab’s DZero control room.
The two-lepton analysis by Kehoe and SMU post-doctoral researcher Peter Renkel looked at data taken over four years during high-energy collisions at Fermilab, a Department of Energy proton-antiproton collider in Batavia, Ill.
The two-lepton analysis is one of almost a dozen analyses of the mass of the top quark at a Fermilab experiment called “DZero.” The DZero experiment involves 500 physicists and is one of Fermilab’s two large experimental collaborations of scientists. The top quark mass was first observed simultaneously by these two experiments. Several measurements of the top quark’s mass from these two experiments are combined to a “world average” value.
The two-lepton analysis contributed to the latest world average measurement. The analysis looked at particles resulting from smashing protons that break apart and disintegrate. The events are very rare, and the detector can’t see two of the important “ghost” particles — neutrinos — produced by the collision. However, the two leptons are well-measured events and are not seen in other “background” collisions where top quarks are not produced. This allows a rapidly improving precision to be achieved.
The two-lepton research was published in November in the article “Measurement of the top quark mass in final states with two leptons” in “Physical Review D,” the American Physical Society’s journal of particles, fields, gravitation and cosmology. SMU physicists collaborated on the research with scientists at Boston University. The SMU portion of the work was funded by the Department of Energy.
The new world average is so precise that it constrains more tightly than ever the range of possible measurements for the mass of the Higgs, Kehoe says.
If the Higgs does prove different than currently expected, physicists may have to rework their long-standing theoretical framework, known as the Standard Model. Scientists worldwide are hoping to validate the Standard Model — which has worked well for more than 30 years to explain everything from radioactivity to computer chips — by actually observing the Higgs.
“The new results may be an indication that the Higgs boson has different properties than the Standard Model indicates,” Kehoe says. “It’s very difficult to devise a theory without some mechanism that mimics fairly well the Higgs mechanism. But if the underlying cause of this mechanism is significantly different, that will have a major impact on the fundamentals of the Standard Model. It could point to something deeper than the standard Higgs boson at work, and that is very interesting.”
The Standard Model of Fundamental Particles. Credit: Fermilab
The measured value of the top quark mass may even go beyond constraining the standard Higgs. It may suggest that our current understanding of the Higgs is not correct, he says.
If the Higgs does not show up where the constraints indicate, the top measurement may force consideration of new theoretical possibilities that lie outside the existing Standard Model, Kehoe says.
Previous measurements have put the top quark at almost the mass of a gold atom. The new world average measurement puts the top quark at about 186 times the mass of the proton. While the value has changed only a small amount from previous measurements, the percentage of error on the measurement is progressively smaller, in this case less than 1 percent.
“If we make a precise prediction of where the Higgs is and it’s not there, then something is wrong. We’ve just found a major flaw in the model,” says Kehoe, whose work has focused for 16 years on the top quark, including as a graduate student on DZero working directly on the discovery analysis. “It would tell us that the model is oversimplified and that reality is much more complicated.” — Margaret Allen
After a huge success in first testing, followed by a very public meltdown last September, the Large Hadron Collider may be ready for action again as early as June.
But before the science can proceed, the world’s scientists must come to terms with the complex organism they have created, says one project manager.
“We will have to understand the detector first,” says Ryszard Stroynowski, chair and professor of physics at SMU.
Stroynowski is U.S. Coordinator for the Liquid Argon Calorimeter, the literal and experimental heart of ATLAS, the largest particle detector in the LHC array.
Pictured right: Work progressing in the LHC tunnel.
Photo courtesy of CERN.
The first priority for operation of the ATLAS detector is “to get all those billions of elements to work together in synch again,” Stroynowski says. “We want to see during the summer whether the circulating beam will induce any noise in the system.”
Stroynowski leads an SMU delegation that includes Fredrick Olness, professor of physics, and Robert Kehoe and Jingbo Ye, assistant professors of physics, all in Dedman College. Kehoe is currently at CERN for his research.
The SMU team is focusing on three projects in parallel:
improvements of the graphic and software interfaces for control and monitoring of the detector and of the quality of its data
preparation of the software packages to analyze the data
design and prototyping of the modifications of the readout electronics that will be needed for future upgrades of the experiment to much higher-intensity beams — a six-year research and development project led by Jingbo Ye in SMU’s Physics Electronics Lab.
The LHC is considered the world’s largest physics experiment. The particle accelerator is a 27-kilometer circular tunnel that lies 100 meters underground near Geneva on the French-Swiss border. It uses a magnetic field to propel high-energy protons into each other.
A mechanical failure in September 2008 damaged 53 of the super-sized magnets that power and focus the accelerator’s beams. The final replacement magnet was lowered into place April 30. Repairs in the tunnel now focus on connecting the magnets together and installing new safety and monitoring systems to prevent similar incidents from happening again.
In addition, the 37 damaged magnets that were replaced by spares will be refurbished to serve as spares themselves. Sixteen magnets sustained only minimal damage and were repaired and reinstalled.
The earlier malfunction has resulted in a frustrating wait — one that has had a “rather demoralizing” effect on the students and postdoctoral fellows whose time at the LHC may come and go during downtime, Stroynowski says. Yet the importance of protecting the vast high-energy array from future trauma can’t be overstated, and “the goal is worth the wait, as the payoff may be enormous,” he says.
Scientists and technicians at the European Organization for Nuclear Research — called by its acronym, CERN — in Geneva have maintained an aggressive rehabilitation schedule. The ATLAS detector itself was closed on May 5, marking an end to checks and re-checks of the electronics, cables and other connections. Repairs to the accelerator’s underground ring are scheduled to be completed at the end of May.
Beams will start in June, initially at a relatively low 450 gigaelectron volts (GeV) per beam to ensure the integrity of the new parts and connections. Scientists will raise the energy over a couple of days to 2 teraelectron volts (TeV) per beam, and finally to the LHC’s target operational level of 5 TeV per beam.
The ATLAS team will start taking shifts in July and expects to have useful data starting in October 2009, Stroynowski says. The LHC will then run continuously for 11 months.
Stroynowski says he doesn’t expect any major discoveries by this time next year, but that he hopes “significant results” will come early in 2011.
The LHC’s proton collisions release even smaller pieces of matter, and the Atlas particle detector helps measure the tracks they leave. The huge, international project is directed at finding the “Higgs boson,” a subatomic “God particle” that physicists believe could help explain the origin of our Universe.
The theory behind the Higgs boson holds that all particles had no mass just after the “Big Bang.” As the Universe cooled and the temperature fell below a critical value, an invisible force field composed of subatomic particles called the “Higgs boson” developed throughout the cosmos. Particles that interact with the field gain mass and particles that never interact have no mass. But the theory remains unproven because no one has ever seen the Higgs boson at work. — Kathleen Tibbetts
SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with Dr. Stroynowski or to book him in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.
SMU is a private university in Dallas where nearly 11,000 students benefit from the national opportunities and international reach of SMU’s seven degree-granting schools. For more information see www.smu.edu.
