The LHCb VELO upgrade

The upgrade of the LHCb experiment, planned for 2019, will transform the experiment in a trigger-less system reading out the full detector at the maximum 40 MHz event rate. This will enable the detector to run at instantaneous luminosities of 2×10³³ cm^-2s^-1 and probe physics beyond the Standard Model in the heavy flavour sector with unprecedented precision. The Vertex Locator (VELO) is the silicon detector surrounding the interaction region. The current detector will be replaced with a pixel system designed to accumulate an integrated luminosity of 50 fb^-1 and equipped with data driven readout. The heat generated will be removed by bi-phase CO2 coolant circulating in microchannels within 400 um thick silicon substrates. Additional advantages of the microchannel cooling are a perfect CTE match with the silicon ASICs and a reduced material budget. The upgraded VELO will provide robust pattern recognition and fast reconstruction to the software trigger. In this document the current status of the VELO upgrade will be described and latest results from operation of irradiated sensor assemblies will be presented.