Pawel de Barbaro

Pawel de Barbaro, senior research associate in experimental high energy physics at the University of Rochester, died of cancer on 15 February 2025 at his home in Saint-Genis-Pouilly (France) on the outskirts of the CERN laboratory in Geneva. He had worked at the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider since 2003.

Born in Krakow, Poland, on 17 December 1959, de Barbaro completed his MSc in physics at the Jagellonian University in Krakow in 1984. He moved on to the University of Rochester and did his graduate research in Arie Bodek’s group, initially working on the E140 electron scattering experiment at the Stanford Linear Accelerator Center (SLAC) and then continuing his PhD research in neutrino physics. He did his dissertation on a “Search for Neutral Heavy Leptons from Neutrino–Nucleon Interactions at the FNAL Tevatron” and earned his PhD in 1990.

He continued at the University of Rochester as an SSC Postdoctoral Fellow and played a major role in the research and development of the tile/fiber readout of scintillator sampling electromagnetic and hadron calorimeters. Tile-fiber readout was a new technology that was being developed for detectors at the Superconducting Super Collider (SSC). Initially, the R&D was focused on using optical cement to glue green wavelength shifting optical fibers in grooves in large area scintillating plastic planes. In 1992, Bodek and de Barbaro developed an alternative technique using ball-grooves in the scintillator planes to trap the optical fibers, thus eliminating the need for optical cement and greatly simplifying the construction of arrays of large area scintillation detectors. We now refer to these arrays as Megatiles (as proposed by de Barbaro).

After the SSC cancellation in 1993, de Barbaro played a major role in the construction of the Plug Upgrade Calorimeter for the Collider Detector at Fermilab (CDF). This was the first large detector to utilize the new Megatile technology. Following the successful performance of the CDF Plug Upgrade Calorimeter, Megatile technology was chosen for the construction of the Hadron Calorimeter (HCAL) for the CMS experiment at the Large Hadron Collider. De Barbaro was named Level 3 Manager for CMS HCAL Optics Production, responsible for the design and construction of the optical readout system for the CMS Hadron Barrel Calorimeter. He was the principal author of the Nuclear Instruments and Methods article summarizing CMS HCAL test beam results.

From 2000–03, de Barbaro served as the chairman of the CMS HCAL institutional board. In 2003, he moved to CERN and served as the CMS HCAL Commissioning Coordinator from 2003 to 2008. He was an ideal person for this role. In addition to various technical skills, de Barbaro was a remarkable source of energy, enthusiasm, and passion. His fluency in English, French, Polish, and Russian served him well because the construction and commissioning of the detectors at CERN involved teams of technicians from many countries working together.

After the construction and commissioning of HCAL, de Barbaro took on a variety of project management positions, including CMS HCAL Operations Manager (2008–10), Deputy CMS HCAL Project Manager (2011–12), CMS HCAL Upgrade Project Manager (2016–18), and CMS HCAL Project Manager (2012–16 and 2018–20). In 2021, the CMS experiment started construction of a High Granularity Calorimeter (HGCAL) using silicon wafer technology, and de Barbaro was named Coordinator of CMS HGCAL Cassette Assembly Center at CERN.

Throughout his career, he supervised a large number of graduate students and postdocs for many institutions, focusing on detector commissioning, radiation damage studies, test beam data, and more. Always warm-hearted and ready to help, he inspired everyone around him with his kindness and compassion. After the outbreak of the war in Ukraine, de Barbaro became deeply involved in assisting Ukrainian families, bringing many to France and helping them settle.

Pawel de Barbaro will be remembered as dynamic physicist who played a major role in the development of new technologies and in managing the construction and operations of large and complicated detectors, as well as a remarkable source of energy, enthusiasm, and passion.

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