641 B
641 B
For the He flow to the flight tube or other components we have a flow meter mounted to the back side of the KB mirrors.
This is a Q-Flow from Voegtlin without calibration. The scale is given in millimeters.
A rough calibration with N2 yields for the flow rate:
When used with He gas this has to be multiplied with a factor of 1.25 (at 20 deg C and atmospheric pressure). With a reading of 120 mm the corresponding gas flow is 22 L/min of He.

