JLab Welcomes New Experimental Hall Leader

  • Patrick Achenbach, new Hall B Leader

JLab Photo: Aileen Devlin

Physicist Patrick Achenbach takes the helm of Jefferson Lab’s Experimental Hall B

NEWPORT NEWS, VA – The U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has appointed Patrick Carsten Achenbach as the new leader of Jefferson Lab’s Experimental Hall B. The appointment comes after an international search.

Long before he was chosen for this position that leads studies of the tiniest particles in nature, Achenbach was fascinated by the biggest. As a schoolboy in his native Germany, he was intrigued by astronomy and the workings of the universe.

“But then I learned very quickly that this also relates to some fundamental research in physics - in nuclear and particle physics, where we study the Big Bang and the particles created 14 billion years ago, which are now making up the matter in the universe,” said Achenbach.

“It’s not a single topic. It’s all interconnected. Physics really describes the universe on many scales. It describes it on the largest scales of millions and billions of light-years and it can also describe it on the tiniest scales inside of the nucleus,” he said.

The star-struck student went on to become an experimental physicist investigating the fundamental makeup of the universe by using powerful particle accelerators to delve deep inside atomic nuclei.

Now in his new position leading one of four experimental halls at Jefferson Lab, he will promote cutting-edge nuclear physics using the most powerful accelerator of its kind in the world: the Continuous Electron Beam Accelerator Facility, or CEBAF. More than 1,600 nuclear physicists worldwide come to CEBAF, a DOE Office of Science user facility, to conduct their research.

Leading an experimental hall

Achenbach began his tenure Sept. 1.

“I’m very happy to be here,” he said. “It’s a great lab, a world-leading lab in this type of accelerator-based nuclear physics. I’m proud to be part of the group here, and of the team.”

An experimental hall relies on a vast network of moving parts and precision instruments, including an injector to produce the particle beam; cryogenics systems to supercool components that accelerate the beam; electromagnets to steer it around the accelerator; detectors that can run as big as a house; complex electronics and computing systems; and a small army of highly skilled technicians, engineers and physicists to keep it all humming.

For each experiment, the particle beam shoots around the nearly mile-long underground racetrack-shaped accelerator at nearly the speed of light. With each lap, the beam gains energy. Once it gains the right amount of energy, it’s directed into an experimental hall, where it smashes into a chosen target. There, detector systems with more than 100,000 electronic channels - or electronic “eyes” - can see and register the fleeting and often rare subatomic particles created in the collision.

“And all of this needs to be coordinated, and all of these great people need to work together,” Achenbach explained. “So that, in the end, we get results out or we get data that can be analyzed and we can do our research, and maybe we have discovered something new, or we understand something new, or we expand our knowledge.”

As hall leader, Achenbach will coordinate staff, instruments and experiments, as well as help choose future experiments from among the recommendations of an international advisory committee and the priorities or restrictions of the hall. As he settles into his new position, he plans to look for ways to best develop the hall even more.

Discussions are underway, he said, to potentially upgrade CEBAF and increase its energy. Greater energy means even more compelling experiments and the potential for even greater discoveries. The lab is also considering producing a different type of beam - a positron beam - for new kinds of experiments, he said. A positron is the antimatter counterpart of an electron.

Such upgrades and enhancements would require adapting the experimental halls to accommodate them.

A background in physics

Achenbach most recently served as a professor of experimental physics at the Johannes Gutenberg University in Mainz, Germany. He has a strong background in the operation of experiments and experimental equipment, with leadership roles at electron accelerator and spectrometer facilities. In 2009, he also engaged in research at Jefferson Lab.

He studied physics and mathematics at Justus Liebig University in Giessen and earned a doctorate at Johannes Gutenberg University before conducting postdoctoral research at the University of Oxford.

He has served on the Japan Proton Accelerator Research Complex (J-PARC) program advisory committee, as well as on various executive and collaboration boards and steering and collaboration management committees.

He worked on the H1 inclusive deep inelastic scattering experiments at the German laboratory DESY; in the A2 and TAPS collaborations at the Mainz Microton accelerator (MAMI) to study nucleon resonances and excitations and pion/eta photoproduction; and in A4 collaborations at MAMI to carry out elastic electron scattering, parity violation and strangeness form factor experiments. He was also involved in cosmic ray and atmospheric neutrino science.

He was a member of the A1 Collaboration at Mainz and the PANDA Collaboration at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt. He has many years working within the A1 Collaboration on strangeness production, hadron spectroscopy and hypernuclei. He is also involved in the light dark matter searches and beam dump experiment at MESA.

By Tamara Dietrich

Contact: Kandice Carter, Jefferson Lab Communications Office, kcarter@jlab.org


Jefferson Science Associates, LLC, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy's Office of Science. JSA is a wholly owned subsidiary of the Southeastern Universities Research Association, Inc. (SURA).

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science