In ultra-high empty pocket metrology, faith was a criminal offense.
The turbomolecular pumps had pulled the annular cavity beneath the five-hundred-ton Harmonic Core down to one-hundredth of a Torr.
The Bourdon dials were pegged, and the digital Pirani gauges showed a stable empty pocket.
To an inexperienced engineer, a stable gauge reading was proof of success.
To Giles Croft, a stable gauge reading proved only that the roughing pumps were currently running faster than the surrounding leak rate.
Outgassing from rubber grease, water vapor evaporating off steel surfaces, or tiny porous channels through the pipe rim could easily mask a fatal flaw.
The only acceptable proof of a hermetic seal was helium mass spectrometry.
Giles stood on the lower gallery beside a portable, shock-mounted stainless-steel cabinet containing a magnetic-sector mass spectrometer.
