Radiation-Hardened ADC Chip Powers ATLAS Particle Detector todayheadline

Inside CERN’s Large Hadron Collider, where protons collide at nearly the speed of light, the radiation is so intense it fries conventional electronics in seconds.

Yet a team of Columbia engineers has designed a silicon chip that thrives in this hostile environment, capturing precise data from each subatomic blast. Their new radiation-hardened, 8-channel analog-to-digital converter (ADC) will be at the heart of the ATLAS detector’s liquid argon calorimeter, powering the next decade of discovery at the upgraded High-Luminosity LHC (HL-LHC).

Why Particle Physics Needs a Custom Chip

The HL-LHC is set to increase particle collision rates tenfold, generating a torrent of data—and radiation. Each collision in the ATLAS detector leaves an electrical signature in supercooled liquid argon. These delicate pulses must be digitized at 40 million times per second (MSPS) with near-perfect fidelity.

“We tested standard, commercial components, and they just died. The radiation was too intense,” said Rui (Ray) Xu, a Columbia Engineering PhD student. “We realized that if we wanted something that worked, we’d have to design it ourselves.”

That effort led to a custom ADC chip with:

• 15-bit resolution and 14.2-bit dynamic range
• Sampling rate of 40 MSPS
• Radiation tolerance for a 12-year mission
• Built-in foreground calibration and error correction

How the ADC Stays Stable Amid Particle Storms

The chip is engineered using radiation-hardening-by-design (RHBD) techniques: triple modular redundancy (TMR) for control logic, robust metal-insulator-metal capacitors, and conservative circuit layouts that mitigate ionizing damage. It runs entirely on a 1.2V supply and integrates all necessary digital and analog systems on-chip, minimizing external vulnerabilities.

“The next discoveries made with the LHC will be triggered by one Columbia chip and measured by another,” said Peter Kinget, professor of electrical engineering at Columbia. The trigger ADC, which selects the most interesting collisions in real-time, is already in use. This new data acquisition ADC handles the precise digitization of the selected signals.

One Chip, 365,000 Times

The ATLAS calorimeter contains over 180,000 channels, each requiring dual gain paths to capture the full dynamic range of energy signals. This means more than 364,000 ADC channels must function flawlessly despite intense radiation and temperature swings.

The team’s chip passed rigorous radiation testing at Massachusetts General Hospital and met CERN’s lifetime dose thresholds. Single-event upsets (SEUs)—brief digital glitches caused by particle hits—were within tolerable limits, and no device ever needed to be power-cycled.

According to performance testing, the chip exceeds the calorimeter’s required signal-to-noise ratio (SNDR) and maintains high resolution even near the Nyquist limit. Measured performance includes 11.4 effective bits and SNDR of 70.3 dB, which is rare in radiation-hardened designs.

Designed by Physicists and Engineers, for Physics

Beyond its technical specs, the chip is a case study in cross-disciplinary innovation. Electrical engineers at Columbia and the University of Texas collaborated closely with ATLAS physicists to ensure the design met both physics goals and harsh hardware realities.

“The opportunity as an engineer to contribute so directly to fundamental science is what makes this project special,” said Xu, who joined the project as an undergraduate and saw it through to full production.

With the final ADC design now validated and mass production underway, these Columbia-designed chips will play a central role in the HL-LHC upgrade. They are expected to help researchers explore lingering mysteries of the Higgs boson and potentially detect new physics phenomena not yet imagined.

Journal: IEEE Open Journal of the Solid-State Circuits Society
DOI: 10.1109/OJSSCS.2025.3573904
Publication Date: May 28, 2025

Related