Like many ATLAS collaborators, Troels Petersen’s current project is not his first CERN experience. He came here a decade ago as a summer student on NA48 and NA59, working on kaons and polarised photon beams.

“CERN was so cool!” he recalls, though the way in which he and his compatriots expressed their enthusiasm was a bit dubious. “We stole anything that said ‘CERN’ on it. To this day, I keep my best suit on a hanger that says ‘CERN’ in gold letters.”

Between that summer and his return to CERN in January of 2007, his education and research took him back to Copenhagen, to Berkeley and Palo Alto California, Paris, and Sydney. He received both his undergraduate and masters degrees from the University of Copenhagen, doing research at Lawrence Berkeley Laboratory for the latter. For his doctorate, he attended the University of Paris XI (Orsay). Again, he did his research in sunny California, working on the b-physics experiment BaBar at Stanford Linear Accelerator Center.

“Even doing my thesis on another experiment – which I loved – I always knew I’d work on ATLAS discovery physics,” Troels says. Although he spent two years as a post-doc in Copenhagen and Sydney, he was already collaborating on the experiment.

Ties with the Niels Bohr Institute at the University of Copenhagen, as well as a healthy interest in particle identification, brought him back to CERN. He currently works with the Transition Radiation Tracker group, picking out electrons from the trails left by various charged particles in the gas-filled straws of the detector. He’s also involved with analysis to measure the mass of the W boson more precisely, the results of which have recently been accepted by ATLAS for publication in the wider world.

Troels spends most of his time at CERN behind a computer, writing programs. However, he did a brief stint in the pit, “carrying heavy things to the top of ATLAS”. He suspects, “I think they were using more my size than my wit.”

Asked how he spends his free time, Troels quips, “I go home and think about work.” The statement is quickly retracted, but then he adds, “Often in the mornings, I think about where I got stuck last night.” Should inspiration strike, he’s immediately on his way to the office, eating breakfast in the car if he thinks of it.

Troels doesn’t let work dominate all of his time, despite his passion for physics. He is engaged in the CERN squash and football clubs, and tentatively, the sailing club. “Being from Denmark, I’m more of an ocean sailor than a lake sailor,” he notes. He has his own boat at Svanemølle Harbour in Copenhagen, the 20-foot Artemis.

Troels shares his penchant for seafaring with his father, skipper of the 38-foot Gypsy. Every June, they team up with four friends to race the Gypsy in Denmark’s “Sjælland Rundt”, translated “Around Sealand.” The two day, 225 nautical mile race starts and ends in Elsinore, the setting of Shakespeare’s Hamlet.

Speaking of Hamlet, Troels is also an avid reader of literature. “During my PhD, I had to take the train, so there I read a lot of the classics.” It may be unsurprising that Homer’s Iliad and Odyssey are among his favorites. He has expanded his repertoire since, venturing into modern fiction and travel writing.

Troels is not content to merely read about travel, though. He has visited southern France, Berlin, Paris, London, Italy, and Tunisia since his return to Geneva. Taking sage advice from a Copenhagen travel agency, he says with a grin, “I try to cover the Earth before the earth covers me.”