EXPERIMENTAL STUDY ON THE EFFECT OF THE FLOW CONDUCTANCE OF THE VACUUM MEASUREMENT STRUCTURE ON THE VACUUM MEASUREMENT

The interlayer vacuum is the main factor that affects the vacuum insulation performance of the cryogenic vessel.The result of vacuum measurement is not only related to the measurement accuracy of the vacuum gauge，but also to the flow conductance of the vacuum measurement structure.The vacuum measurement system was built and two different flow conductance of the vacuum measurement structure were designed.In the experiment，the actual situations of the vacuum measurement system were simulated in the high vacuum multilayer insulated cryogenic vessel.The vacuum under the two structures were measured and analyzed.The results show that the flow conductance of the vacuum measurement structure greatly affects its vacuum measurement.Large flow conductance of the structure can ensure better accuracy of the result measured by the vacuum gauge on this structure in shorter pumping time.The analysis results provide certain references to design，experiment and usage of the vacuum measurement system of the cryogenic vessel.