Hello there. I am struggling with some gas flow calculations that, I think, should be quite basic. However, I think that I miss the knowledge background for it. I have a setup that I am showing in the attached file but here are more details: -I have a vacuum chamber pumped with a turbo pump to a few 10-5 mbar. -A gas ligne brings a noble gas into the chamber. -The gas is delivered through a micro-pipette. -The micro-pipette diameter is 100um where the gas leaves the nozzle for the chamber and this diameter is slowly increasing until it is 2mm at the other side of the micro-pipette where it is connected to the gas line. -On the gas line, just before the ligne goes into the vacuum chamber, there is a manometer. I would like to calculate the gas flow rate from the pressure measured on the manometer but I don't know how to proceed because it can be very different depending on the flow type etc. and I don't know how to determine the flow type. Does someone has any idea how I should do? Any reference book would be very welcome too. Thanks in advence.