Serie CERN-ARCH-BEUSCH-W-05 - OMEGA Films materials

Photographs, Paper and Films
47 Photographs in black and white format of 10.5 x 8.5 and two photos measuring 14.5 x 10.5 cm.

Personal residence of Werner Beusch

The collection was donated to the CERN Archives by Christophe Beusch in September 2025

"This series contains photographic, films and print-out related to the OMEGA Spectrometer. This collection contains 47 photographs in black and white with a format of 38 photos measuring 10.5 x 8.5 cm and two photos measuring 14.5 x 10.5 cm. The camera used was a polaroid as written on the back. It also contains 15 developed films in black and white with various of format.

The photographs show a graphic of a dotted line and some photos probably shows his office and the machine for experiments used for particle-detectors. It shows a particle tracks.  "

Historical note on the CERN OMEGA Spectrometer project

The OMEGA Spectrometer was a cornerstone of particle physics research at CERN for 25 years. Its name is an acronym for “Optimal Magnetic Electronic General Apparatus”. The project was first proposed in 1968 by a group of physicists and engineers known as the “Omega Project Working Group”. Their vision was to evolve the concepts of the "Wilson Chamber" also known as "Cloud Chamber” into a high-tech electronic detection system.

They began operation in 1972 under the guidance of the original 1968 group. OMEGA was design as a versatile “electronic bubble chamber”. The facility utilized a massive superconducting magnet and spark chambers to track and analysed the movement of particles.

While OMEGA was a collective achievement of the CERN community rather than the work of a single inventor, Werner Beusch stands out as a central figure. A true pioneer, Beusch was instrumental in the project’s development and is specifically credited with designing the “trigger” system. The essential electronic component that signalled the spectrometer to record specific particle events.

After 25 years of groundbreaking service, the OMEGA Spectrometer was decommissioned in 1996. Its shutdown was a strategic move to make space for a new project and construction. Known as today, the Large Hadron Collider (LHC), the world’s most powerful particle accelerator. Despite the closure of OMEGA, it was an accomplishment for CERN. 

Wilson Chamber / Spark Chamber

The cloud chamber, also known as the Wilson chamber, was invented in 1911 by a Scottish physicist Charles Thompson Rees Wilson. It serves as a particle detector for ionizing radiation by utilizing a sealed environment containing a supersaturated vapor of water alcohol. When a charged particle enters the chamber, it interacts with the gas molecule, knocking off electrons via electrostatic forces. This process leaves a trail of ionized gas particles that act as condensation nuclei, forming visible liquid droplets that reveal the particle’s trajectory.

The spark chamber is another type of detector that visualizes the paths of subatomic particles, but it operates using high-voltage electricity rather than vapor. It consists of stack of metal plates immersed in an inert gas, such as neon. When a charged particle, such as cosmic ray, passes through the plates, it leaves a trail of ions that triggers a series of bright, visible along its path.

While both instruments make invisible particles visible to the naked eye mechanisms differ: the cloud chamber relies on the condensation of supersaturated vapor, whereas the spark chamber uses an intense electric field to create luminous discharges. Eventually, these visual methods were replaced by electronic detectors, such as the multi-wire proportional chamber used in the OMEGA spectrometer, which allowed for faster data collection and more precise digital analysis.