The Beam Gas Vertex profile monitoring station for HL-LHC

A new instrument is under development for the High Luminosity upgrade of the Large Hadron Collider at CERN (HL-LHC) to provide non-invasive transverse beam size measurements throughout the full acceleration cycle. The Beam Gas Vertex (BGV) monitor consists of a tank supplied with gas at very low pressure attached to the LHC beam pipe with a series of particle tracking stations located downstream outside vacuum. Inelastic collisions between the beam and the gas target produce secondary particles that are detected by the tracking stations. The beam size is measured from the spatial distribution of several thousand beam-gas interaction vertices, which are identified by means of reconstructed tracks. A demonstrator device, operated over several years, has proven the feasibility of the BGV concept and has motivated the development of a fully operational device for HL-LHC. The status of current design studies for the future instrument will be presented, with particular emphasis on potential tracking detector technologies, readout schemes, and expected performance.