1. 9 December 2011Eddy Jans 0 LHCb-VELO CO 2 cooling plans CO 2 - meeting Present VELO - physics running in 2012 - LongShutdown1 2013&2014 - physics running in 2015, 2016 and 2017 Upgraded VELO - cooling plant - cooling of VELOpix-modules

2. 9 December 2011Eddy Jans 1 CO 2 - meeting Present VELO Physics running in 2012 nothing foreseen, except that in January 2012 two chillers and two CO 2 pumps have to be serviced by Seicar and Nikhef, respectively. LongShutdown1 2013&2014 Very likely the LHCb beam pipe will be replaced. This alone has already serious consequences for the state of the VELO-detector: temperature and pressure regulation. Physics running in 2015, 2016 and 2017 Need to guarantee reliable (=continuous) cooling at the lowest possible temperature.

3. 9 December 2011Eddy Jans 2 CO 2 - meeting Upgraded VELO Contains very many (technical) challenges: data processing, data rates, data transfer, sensor technology, radiation hardness, mechanics, cooling, etc. At present Nikhef is involved in development of a VELOpix readout chip and expressed interest to get involved in the module layout and its cooling design  possibly need for an upgraded cooling plant and certainly for a new cooling pipe/module interface. The installation of the LHCb-Upgrade is scheduled for 2018. Whether or not an upgraded cooling plant will be necessary depends on the required operational temperature and the total heat produced. At present there are too many unknown factors to give a serious prediction.

4. 9 December 2011Eddy Jans 3 CO 2 - meeting One VELOpix-module will consist of 4 units with 3 pixel-chips each. Each chip is expected to dissipate  4 W. substrate made of CVD-diamond or TPG First successful attempts of direct metallization of the diamond. 1 2 3 456 78 9 10 11 12 Front-side Back-side

5. 9 December 2011Eddy Jans 4 Investigate different i.types of cooling pipe (Phynox, invar, s.s., microchannels, etc.) ii.ways of routing iii.ways of attachment (optimize the surface of contact) sensor chip substrate cooling pipe CO 2 - meeting The large temperature drop observed in the present cookie + hybrid setup, strongly suggests the need for a design in which the cooling pipe and module form an integrated unit.

6. However, this brings up the problem of where to choose the connection point between the cooling fluid supply line and the module. Remember: the modules are only separated from the beam vacuum by an RF-box of 0.3 mm. Some of the present ideas for the connection point: close to the module. Need to investigate the vicious influence of orbital welding or brazing on very nearby modules, at the flange of the VELO-vessel, outside the vessel. Many novel and interesting engineering aspects in the project, that could be designed, built and tested at Nikhef. Choice of technology (strips/pixel and what kind of module and cooling) is foreseen for end of 2013 / beginning of 2014, so in 2 years from now. 9 December 2011Eddy Jans 5 CO 2 - meeting