At about half past nine CET this morning, for the first time since the Large Hadron Collider (LHC) started up after two years of maintenance and repairs, the accelerator delivered proton-proton collisions to the LHC experiments ALICE, ATLAS, CMS and…

The Tracker is a subdetector that is located closest to the collision point of the LHC’s particle beams inside the CMS detector. It must face an onslaught of billions of particles flying through it each second of operation. To mitigate the effects…

CMS has many different safety systems installed in the underground experimental area. These are designed to protect the detector and all the associated electronics as well as the cavern itself. In case of fire, the last line of defence is the High…

From the CMS experimental site at Cessy, France, located at Point 5 on the LHC ring ————— After a well-deserved Christmas break, work has resumed at Point 5 at an unabated pace. With an extremely busy 2013 behind us, all teams are now focusing their…

The first part of the CMS endcap calorimetry, as seen by particles coming from interactions in the centre of the detector, is the "ECAL Preshower" or "ES" for short. "ES−" and "ES+" are used to distinguish the two ends of this subsystem. The ES is…

The central hadron calorimeter (HCAL) of CMS consists of the barrel (HB), the endcap (HE), and the outer (HO) regions. The HO consists of one or two scintillator layers and uses the metal of the magnet system as an absorber. So far, the HO has been…

A fourth station –– called RE4 –– will be added to the CMS endcap muon system during the ongoing LHC Long Shutdown (LS1). The CMS muon system consists of three different sub-detectors: RPCs (Resistive Plate Chambers), DT (Drift Tubes) and CSC (…

CERN’s surveyors conduct diverse measurements to ensure, for example, accurate positioning of magnets, detectors and other equipment. They do so using techniques such as laser tracking and 3D scanning. Two weeks ago, the surveyors were busy…

Two new wheels of the Resistive Plate Chambers (RPCs) of the muon system are being installed during the LHC’s first Long Shutdown (LS1). These will add to the six lateral wheels in the (outer) endcaps, which currently make up the RPC system with six…

From the CMS experimental site at Cessy, France, located at Point 5 on the LHC ring ————— The past two weeks have seen several pivotal steps taken towards achieving some of the key goals for CMS during the LHC’s first Long Shutdown (LS1). On 21…