Microchannel Cooling techniques at LHCb

The thermal management of the LHCb Vertex Detector Upgrade will be provided by evaporative carbon dioxide circulating in micro-channels or thin tubes. The main plan is to use micro-channels embedded in silicon due to its excellent cooling performance, no thermal expansion coefficient mismatch with electronics and minimal material budget. However, two back-up alternatives are also being investigated: stainless steel tubes embedded in ceramics and titanium 3D printing. The latest prototyping results concerning all cooling substrates alternatives will be described in this proceedings.