Archives of Omega Spectrometer Group

Identity Statement [Top]

Reference code(s)



Archives of Omega Spectrometer Group


1959 - 1992

Level of description


Extent of the unit of description

40 boxes, 122 items, 5 linear metres

Context [Top]

Name of creator

Omega Collaboration

Administrative history

In April 1967 the Omega Project Working Group was set up. This Group consisted of the following members : W.F Baker, W. Beusch, G. Brautti, G. Cocconi, B. French, O. Gildemeister, M. Martin, A. Michelini, M. Morpurgo, B. Nellen, G. Pettrucci, P. Preiswerk, E. Quercigh, B. de Raad, C. Rubbia, K. Tikkel and P. Zanella.

The genesis of Omega is described in CERN Document NP-68-11 of May 1968: 'Proposal for a large magnet and spark chamber system'. The initial concept was for an 'electronic bubble chamber' - a large magnetic volume filled with spark chambers, and able to take a variety of triggers.

In 1968 the Scientific Policy Committee approved the construction of a large spectrometer magnet to be used for high-energy counter spark chamber experiments. It was studied in Nuclear Physics (NP) division, Department of Physics I, directed by P. Preiswerk (1961-1969), H. F. Schopper (1970-1971) and E. Picasso (1972-1975).

In 1976 the departmental structure ceased, NP Division was dissolved, and the experimental program of the SPS accelerator began (Omega Spectromter included). With the advent of the large bubble chambers, expert groups of designers and constructors grew up. Finally, the distinction between those people who design, build and operate the big detectors and those who use them for research was recognized by the setting up of two new CERN Divisions. The staff of NP division went to Experimental Physics Division (EP) and to Experimental Physics Facilities Division (EF).

In 1990 a part of EP Division and a part of EF Division merged to form the Particle Physics Experiment Division (PPE). Omega Spectrometer group moved into PPE Division directed by J. V. Allaby until 1994 and G. Goggi until 1997

Immediate source of acquisition or transfer

Received from Albert Herz.

Content & Structure [Top]

Scope and content

In 1971 Omega started to take shape and was equipped to measure particle tracks. Tracks were photographed and analysed later. 

For five years, i.e. up to 1976, Omega spectrometer was used for research with PS Machine and was installed in the West Experimental Area. Twelve experiments were approved during this period.

In 1976 Omega was adapted for the SPS program. The next ten years (1976-1986) saw interest move away from the study of standard hadronic interactions towards photoproduction, charm production, and more generally QCD-motivated studies, although meson spectroscopy remained an important feature. 26 Experiments were approved during this period.

As the year went on, more and more electronic detectors were unemployed, until finally in 1978 and 1979, Omega's spark chambers were replaced with electronic detectors. 1978 was the last year of the old Omega spectrometer in its optical version.

In 1979 the Omega Prime started with a new vertex detector of proportional wire chambers. Since then, several collaborations installed different detectors, corresponding to their own particular needs, around the main spectrometer corresponding to their own particular needs and therefore its use has often been diversified.

In the last ten years (1986-1996), the study of beauty production took over from that of charm. Meson spectroscopy was concentrated on glueball searches in central production. A strong heavy-ion programme developed, focusing on strangeness and baryon-anti-baryon production. 10 Experiments were approved during this period.

In 1996 Omega spectrometer ceased when the facilities in the West Area were shut down in preparation for the construction of the LHC.

See more details in CERN-97-02

This collection contains minutes of WA7, WA42-62, WA57, WA40, WA69, WA74, R704 collaborations, ELAS notes, Memoranda, Data Handling (DD) reports, Omega publication, slides, etc.

Appraisal, destruction and scheduling information

Nothing was destroyed.


No further accruals are expected.

System of arrangement

The original order has been preserved.

Conditions of access and use [Top]

Conditions governing access

See file level description and the CERN operational circular No 3: rules applicable to archival material and archiving at CERN. In general, records on any subject that are over 30 years old, and all records of a purely scientific nature, may be consulted.

Conditions governing reproduction

Copyright is retained by CERN, no reproduction without permission.

Language / scripts of material

Most of the material is written in English.

Finding aids

Listed to file level in the CERN Archives Database.

Description control [Top]

Archivist's note

Description prepared by Florent Perret.

Date(s) of description

Geneva, the 27th April 2004, Revised 2007.