Fig. 5: Vacuum sensitive array (VSA)-assisted Brillouin system for ETT vacuum distribution measurement.
From: High-spatiotemporal-resolution distributed Brillouin sensing with transient acoustic wave
a Conceptional illustration. The sensing system configuration is the same as that of the TABS. The VSA, consisting of vacuum sensitive units (VSUs) in series, is deployed along the ETT line. b The working mechanism of distributed vacuum sensing. c Digital photograph of the VSA installation along the evacuated tube. Measured BGS distribution in d top and e side views when vacuum degree is 14% (air pressure = -14 kPa). f The BFS variations of the 12 VSUs. The g vacuum sensitivity and h measurement uncertainty of each VSU. i The response to dynamic vacuum variation of the first and last VSUs. j Vacuum measurement range under the VSU with different inner air pressure
