Abstract: Spacce traveling-wave tube (STWT) are used in a wide variety of areas, such as radar, space technology and electron accelerators. The vacuum is one of the basic conditions for the work of STWT. We use ultra -high vacuum exhaust station to obtain a microwave device with the ultimate vacuum better than 5 伊 10 -9Pa; The residual gases in a macro-wave device during thermal degassing was in-situ monitored with quadrupole mass spectrometer ( QMS ). The major residual gases, including but not limited to H2O, CO, and H2, was investigated. It is shown that 36 hours was economically for the baking exhaust time. The operating principle and method of vacuum leak detection using QMS are introduced, and the leak detection was conducted for macro-wave device experimentally. Satisfactory results were obtained and showed that QMS has so predominant advantage that no leak detector can get over. A test platform for measuring the vacuum of the microwave device has been established. After the STWT sealing off the exhaust equipment, sophisticated, storage and high and low temperature test process of vacuum was tested. When the STWT is sophisticated, the vacuum in the device is reduced by an order of magnitude. After 140h, the vacuum of the device rises to 5.0 伊 10-8 Pa under the ion pump. At this time, the vacuum remained basically unchanged after removing the ion pump. Finally, high and low temperature impact experiments were performed and stored at room temperature for 6 months, the vacuum of the STWT is kept in good. These results provide a good basis for analyzing the quality of the STWT.

Key words: STWT, ultra high vacuum, quadrupole mass spectrometer, residual gas, vacuum test