You are here: Home / Infrastructures / Res. Infrastructure
Compact Muon Solenoid (CMS)
Hosting Legal Entity
European Organization for Nuclear Research
Geneva 23, PO: 1211 (Switzerland)
Type Of RI
Coordinating Country
Current Status:
Operational since 2009
Being upgraded since 2013 to 2014
Scientific Description
The Large Hadron Collider (LHC) at CERN collides protons with eight times the energy of the most powerful accelerators built up to now.
Some of the collision energy is turned into mass, creating new particles which are observed in the Compact Muon Solenoid (CMS) particle detector. Like a cylindrical onion, the different layers of the CMS detector measure the different particles. CMS data is analyzed by about three thousand scientists around the world to build up a picture of what happened at the heart of the collisions.
This will help to answer questions such as: What is the universe really made of and what forces act within it? And what gives everything substance? Such research increases our basic understanding of physics and may also spark new technologies that change the world we live in. In 2012, CMS (along with the ATLAS experiment at LHC) discovered a new particle, a Higgs boson, which plays a fundamental role in our Universe.

RI Keywords
CERN, Particle physics, High-energy collisions, LHC
RI Category
High Energy Physics Facilities
Scientific Domain
Physics, Astronomy, Astrophysics and Mathematics
ESFRI Domain
Physical Sciences and Engineering
CMS detector

Detectors consist of layers of material that exploit the different properties of particles to catch and measure the energy and momentum of each one. CMS has: - a high performance system to detect and measure muons, - a high resolution method to detect and measure electrons and photons (an electromagnetic calorimeter), - a high quality central tracking system to give accurate momentum measurements, and a quasi-hermetic hadron calorimeter, designed to entirely surround the collision and prevent particles from escaping. A strong magnet allows to accurately measure very high momentum particles. The magnet is the “Solenoid” in Compact Muon Solenoid (CMS). The solenoid is a coil of superconducting wire with an overall length of 13m and a diameter of 7m, and a magnetic field about 100,000 times stronger than that of the Earth. It is the largest magnet of its type ever constructed. CMS was designed in fifteen separate sections or “slices” that were built on the surface and lowered down ready-made into the cavern. This slicing, along with the careful design of cabling and piping, also ensures that the sections can be fully opened and closed with minimum disruption, and each piece remains accessible within the cavern.

Date of last update: 07/08/2018