HOW PRECISION MEASUREMENT TECHNOLOGY ENABLES GROUND-BREAKING SCIENCE

The High-Luminosity Large Hadron Collider (HL-LHC) under development at CERN, the European particle physics laboratory, headquartered in Switzerland, is set to become the world’s most powerful instrument for gazing into the heart of matter, the fundamental building blocks from which the universe is formed. In the process, it will expand the frontier of what precision measurement technology can achieve.

Front view of Cern's headquarters showing The Cern's Globe landmark building located in Geneva, Switzerland. — The Globe, a landmark building of CERN’s headquarters in Geneva, Switzerland.

Front view of Cern's Compact Muon Solenoid detector technology. — The Compact Muon Solenoid (CMS) detector, which captures 3D images of particle collisions up to 40 million times a second.

The HL-LHC itself is a more powerful upgrade of the original LHC particle accelerator, a 27 kilometer ring of superconducting magnets in which particles smash into each other at close to the speed of light—the particles travel the entire 27 km circuit 11,245 times a second. One billion particle interactions occur every second. Analysis of the results of the collisions led to numerous breakthroughs in the study of physics and the nature of the universe, including most famously the experimental discovery of the Higgs boson, the particle associated with the Higgs field.

1 Billion

THE NUMBER OF NEW PARTICLE INTERACTIONS PER SECOND PRODUCED BY CERN’S LHC.

Higgs Boson is a part of physics’ Standard Model for explaining the universe. Its existence was hypothesized in the 1960s, but experimental proof of its existence was absent until particle collisions at LHC revealed it. CERN is a living demonstration that when scientists harness the capabilities of the world’s most advanced measurement technology, astonishing discoveries emerge—pushing the boundaries of human knowledge.

Over its lifetime, the HL-LHC promises to create ten times more collisions than CERN’s existing particle accelerator providing an even more powerful experimental platform for scientific investigation.

The HL-LHC increases the number of particle collisions in part by focusing its beam into a smaller space. The beam is shaped by ultra-powerful magnets which require a new, more tightly regulated power source. CERN’s engineers have developed one of the most accurate and stable measurement systems ever created in order to measure currents up to 18kA. Employing advanced electronics measurement technology developed at Analog Devices, Inc. (ADI), the circuits helped to deliver a 2x low frequency noise reduction.

Graphics illustrating CERN's HL-LHC particle accelerator collision models and simulations. — CERN’S HL-LHC particle accelerator collision models.

Image Courtesy CERN

THE PRECISION CHALLENGE

Advanced scientific research calls for electronic circuits that reach the extreme edge of measurement technology in terms of stability, precision, sensitivity, accuracy, and reliability. Eric Modica, IC Design Manager, Precision Technology Platforms at Analog Devices, said “HL-LHC’s current measurement noise reduction specification is just one example of a requirement common to advanced scientific endeavors—not only to fundamental physics but medical research and pharmacology, chemical analysis, and materials science.”

COLLABORATION SUPERCHARGES SCIENTIFIC DEVELOPMENT

Leading-edge science involves large-scale endeavors involving multiple departments and teams. Such was the case for the HL-LHC project’s precision measurement system for the magnets’ power source being just one of many development projects running in parallel.

“Frequently, the sheer scale of an endeavor like the HL-LHC project means that a project team presents vendors with a list of key specifications for a given component,” said Daniel Braunworth, Scientific Instruments Segment Manager at Analog Devices. “In theory, the product which best matches the specifications should provide the best performance in the application. In reality, collaboration between precision measurement technology experts and researchers are often key to enabling better tuned solutions with optimized system performance. Through close communication and a discussion of design tradeoffs, researchers can produce better outcomes, enabling the discovery of more scientific insights.”

Image displays the inside of a building where several people are working on CERN's mechanical technologies.

Image Courtesy CERN

A BETTER UNDERSTANDING OF REQUIREMENTS LEADS TO BETTER OUTCOMES

“Matching ADI’s components to HL-LHC’s power source’s key system requirements was the approach we took, saving CERN time and expense while delivering the best performance,” said Daniel Braunworth. ADI is both a trusted precision measurement technology source and partner for CERN as a result of its long heritage developing precision technology.

Analog Devices domain specialists align product offerings with the needs of scientific researchers. ”Our domain specialists worked with CERN engineers to understand their requirements for power control,” said Eric Modica. “The high level objective was to develop an advanced power source measurement system for HL-LHC’s magnets, enabling them to focus a higher magnetic field with higher precision in a much larger volume of space inside the particle accelerator as compared to the nominal LHC.”

This enabled ADI’s measurement experts to work with the CERN team developing the reference voltage used in the high precision digitizer for the HL-LHC magnet power supplies, a key contributor in helping CERN’s power converters achieve drift of less than 10 ppm over the course of a year of operation by more precisely controlling the current supplied to the magnets. The result: ultra-accurate power control enables LHC to precisely control the motion of the particle beams on the required micrometer scale along its 27km circumference.

“Collaboration between the world’s leading measurement technology experts and scientific researchers is key to making systems that can expand the scope of scientific discovery.”
Daniel Braunworth

Scientific Instruments Segment Manager | Analog Devices

PRECISION MEASUREMENT BENEFITS FROM A SPECIALIST’S FOCUS

The measurement technology that the CERN developers drew on for the HL-LHC has been long in the making. Measurement begins in the analog domain, and here, the important parameters of high-performance systems include sensitivity, low noise, linearity, resolution, and drift performance over time.

At the extreme end of scientific endeavor, the demands on measurement technology are also extreme. The production of ultra-high-performance analog technology calls for a remarkable combination of assets, capabilities, and intellectual property built up over many decades of research and investment.

Today’s leading-edge analog solutions are the result of innovations in electronics circuit technology. This includes developing special semiconductor materials alongside the familiar silicon, and wafer fabrication using specialized processes optimized for low noise, high sensitivity, and other features demanded in ultra high precision measurement applications.

Image displays several people working on precision instruments for CERN's technology.

Image Courtesy CERN

SCIENTIFIC ADVANCES AND THE EVOLUTION IN PRECISION TECHNOLOGY

Another example of the continuing evolution of precision analog technology can be observed at LIGO (Laser Interferometer Gravitational-Wave Observatory), operated by the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT). Here, two 4km-long vacuum chambers measure motion 10,000 times smaller than the width of an atom’s nucleus. Such accurate and sensitive measurement technology enables LIGO to look far into deep space, and to detect black hole events which took place more than a billion years ago.

Graphic illustration of graviational wave signals and high-performance analog data signals gathered from the LIGO facilities. — Readings of black hole event gravitational waves detected at the LIGO Hanford and LIGO Livingston sites. The minute offset in timing detection is the result of the distance between the two receiving locations. The time displacement further serves to confirm the accuracy of the high performance analog data signal.

The insight into the nature of the universe provided by LIGO was unprecedented in human history. But it’s in the nature of the scientific project to always hunt the next discovery. If ambitious projects like LIGO are to unearth new insights, measurement technology needs to continue advancing the ability to recover weak signals out of noisy environments while increasing dynamic range. The same drive to detect ever more phenomena with ever more precision is true of all fields of science, from medical researchers trying to better understand the workings of the human body, to the nanoscientists developing the world’s next miracle material.

Just as in the past, future advances at the leading edge of scientific research will depend on leading-edge measurement technology. Today’s developments in advanced semiconductor technology will feed the process. ”At Analog Devices, continued investment in technologies that more effectively detect even the most subtle signals and the world-class expertise of our analog engineers who can implement those technologies continues to produce new approaches to precision measurement circuit design, refine the product fabrication processes, and advance how those technologies interact to deliver new insights to our customers,” said Eric Modica.

SOLVING HUMANITY’S PROBLEMS

Technology advances not only benefit the world’s leading researchers at CERN and LIGO but all of humanity. The world needs advancements in science to solve crucial problems, such as climate change and novel infections, and to deepen our knowledge of our species, our planet, and our universe.