Scans of the Physics Debris Absorbers (TCL) at the 4TeV LHC

At the Large Hadron Collider (LHC), dedicated physics debris collimators (TCL) protect the machine from the collision products at the high-luminosity experiments. These collimators reduce the risk of quenches of superconducting magnets by cleaning physics debris losses. One TCL is installed per beam in IR1 and IR5. Several measurements have been performed in 2012 at 4TeV, with peak luminosity values up to 6:3 1033 cm􀀀2 s􀀀1 to address the need of these devices and optimize their settings. They consist in opening the collimator from its nominal setting to an \open" setting, and observing the evolution of the losses measured by the Beam Loss Monitors (BLMs) downstream. All the 2012 measurements are analysed here, including asymmetric measurement with only one jaw. The evolution of the losses as a function of the collimator setting are presented, as well as the loss proles and the ratio of the losses with TCL in over TCL out.