Measuring High Vacuum
Measurement of high vacuum is done using a nonabsolute gauge that measures a pressure-related property of the vacuum, for example, its thermal conductivity. See, for example, Pacey. These gauges must be calibrated. The gauges capable of measuring the lowest pressures are magnetic gauges based upon the pressure dependence of the current in a spontaneous gas discharge in intersecting electric and magnetic fields.
Read more about this topic: Ultra-high Vacuum
Famous quotes containing the words measuring, high and/or vacuum:
“We recognize caste in dogs because we rank ourselves by the familiar dog system, a ladderlike social arrangement wherein one individual outranks all others, the next outranks all but the first, and so on down the hierarchy. But the cat system is more like a wheel, with a high-ranking cat at the hub and the others arranged around the rim, all reluctantly acknowledging the superiority of the despot but not necessarily measuring themselves against one another.”
—Elizabeth Marshall Thomas. “Strong and Sensitive Cats,” Atlantic Monthly (July 1994)
“What you have said
I will consider; what you have to say
I will with patience hear, and find a time
Both meet to hear and answer such high things.”
—William Shakespeare (1564–1616)
“If it were possible to have a life absolutely free from every feeling of sin, what a terrifying vacuum it would be!”
—Cesare Pavese (1908–1950)