Armenia’s Particle Accelerator

How it started?

Founded in 1943 as a branch of Yerevan State University by renowned physicists Abraham Alikhanov and Artem Alikhanyan, YerPhI quickly became a cornerstone of Armenia’s scientific ambition. Just two years later, high-altitude cosmic ray stations were built on the slopes of Mount Aragats—Nor Amberd at 2000m and Aragats Station at 3200m.

A government delegation led by Brezhnev at the Armenian SSR pavilion at VDNKh, near the particle accelerator model

By the 1960s, the dream went underground—literally. YerPhI’s team began construction on a major accelerator complex, designed for cutting-edge research in nuclear and high-energy physics.

The symbol named "Arus"

As you approach YerPhI, you’ll notice a striking sculpture on your right—a mysterious double-sided figure made of red tuff, standing three meters tall. This is Arus, also known as the "Armenian Sphinx." The name "Arus" is both a common Armenian woman’s name and an acronym for Armenian Accelerator (Армянский Ускоритель). It is said that the title "Armenian Sphinx" was coined by Artem Alikhanyan, founder of the Institute of Physics.

Created by sculptor Arto Chakmakchyan, Arus is more than art—it’s a tribute to the dreams and determination behind Armenia’s scientific rise. And it guards the entrance to the underground halls where science once roared.

Into the Depths: A Fortress of Concrete and Basalt

Next, you’ll spot a large sign in Russian on top of the building to your left: “ЕрФИ.”

In 1965, the LU-75 linear accelerator was completed. Two years later, it was joined by a 6 GeV synchrotron.

Though its raw power can’t compete with modern giants like CERN, this facility was once among the most advanced in the USSR, delivering over 5,000 operational hours annually at its peak.

The Arus synchrotron, with a diameter of approximately 70 meters and a circumference of about 220 meters, was designed to accelerate electrons to an energy of 6 GeV. The accelerator also produced a beam of linearly polarized photons in the 0.9–1.8 GeV range, enabling precise experiments in particle interactions.

Key specifications include:

• Diameter: 70 m

• Commissioning Year: 1967

• Electron Energy: Up to 6 GeV (designed), 4.15–4.5 GeV (operational)

• Photon Beam: 0.9–1.8 GeV (linearly polarized)

• Experimental Setup: Included magnetic spectrometers and neutron hodoscopes for detailed measurements

Scientific Contributions

Arus facilitated a range of groundbreaking experiments in particle physics. One significant study measured the asymmetry of deuteron photodisintegration at photon energies up to 1.8 GeV, using a 90° centre-of-mass angle. This experiment, conducted with a magnetic spectrometer for protons and a neutron hodoscope, challenged existing models of quark interactions by highlighting discrepancies in constituent quark counting rules.

Other research explored:

• Hadronic properties of photons via π-meson photoproduction on nuclei.

• Structures of nucleon resonances through multi-polarization experiments.

• Characteristics of nuclear matter under high-energy conditions.

A notable achievement was the 1970 discovery of X-ray transition radiation, a phenomenon now widely used in particle identification detectors worldwide. Collaborations with scientists from the Joint Institute for Nuclear Research in Dubna underscored Arus’s role in fostering international scientific exchange.

The last full run of the circular accelerator took place in 1998. Operations resumed in May of that year, shifting focus to photodisintegration studies and the investigation of quasi-deuteron disintegration in light nuclei such as helium-4 and lithium-6. These efforts aimed to deepen our understanding of nuclear interactions using the synchrotron’s polarized photon beam.

From Electrons to Isotopes: What Happened Inside

Put simply, a particle accelerator speeds up electrons or protons to near light-speed and smashes them into targets. This lets scientists study the tiniest building blocks of matter. Think of it as an atomic microscope—on steroids.

As I stepped out of the elevator and saw the particle accelerator, a pleasant shiver ran down my spine

At YerPhI, researchers focused on:

• Electron-photonuclear interactions

• Production of medical radioisotopes like technetium-99m

• Transition radiation in monocrystals

• Nuclear resonance structures

• Hadronic properties of photons
  

Thanks to the synchrotron’s precision beamline—designed to eliminate electromagnetic noise and enable low-background experiments—researchers were able to carry out delicate, world-class physics investigations.

I took a photo of Mr. Hakobyan as he explained how the accelerator worked

Many of these experiments, including the development of wide-gap spark chambers and transition radiation detectors, positioned YerPhI as a serious contributor to international scientific collaborations from the mid-1980s onward.

Back to our visit

After passing through the gates, you’re guided to a large round building, where an elevator takes you four floors underground where the accelerator is located.

Every instrument sits on a single elevation surface, with zero tolerance for millimeter error. That’s how precise things had to be. Massive half-meter-thick, lead-lined doors shield the lab—and the outside world—from potential radiation and other hazards.

Inside these heavily reinforced corridors lies what was once a state-of-the-art research machine. Even today, its foundations are solid—scientifically and structurally.

Where It Stands Today

After the collapse of the Soviet Union, YerPhI faced tough times—lack of funding, scarce resources, and a brain drain of specialists. However, it managed to adapt to the changing global scientific landscape, continuing its research and contributing to the broader field of physics.

While large-scale acceleration has stopped, the facility remains partially operational. It’s used for training, detector development, and even international research collaborations.

Behind thick glass, we observed the work in the laboratory

The building may carry the weight of the past, but the minds inside are very much focused on the future.

The display boards told the rich history of the Physics Institute

For the Curious Traveler

YerPhI isn’t your average tourist stop, but it’s a goldmine for those who enjoy science with a twist of Soviet nostalgia. So if you're a traveler looking for more than just churches and khachkars—if you want to touch the edge of atoms and ambition—put YerPhI on your radar. Because Armenia isn’t just old; it’s also brilliant.

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