Veeco MS40, Operation And Maintenance Manual, Page: 119 / 169

Vacuum Instrument Corp.
2099 Ninth Avenue
Ronkonkoma, NY 11779
631.737.0900
Glossary Of Terms Used In
Leak Detection
1. Leak - In vacuum technology a hole, or porosity, in the wall of an
enclosure capable of passing gas from one side of the wall to the
other under action of a pressure or concentration differential existing
across the wall.
2.
Gross Leak - A leak that exhibits a leak rate in the range of 10
-4
to
1 std cc/sec or higher.
3.
Fine Leak - A leak that exhibits a leak rate in the range of 10
-5
to
10
-11
std cc/sec or lower.
4.
Leak Rate - In leak detection practice, leak rate is defined as the rate
of flow (in pressure-volume units per unit time) through a leak with
gas at a specified high pressure (usually atmospheric pressure) on the
inlet side and gas at a pressure on the exit side which is low enough
to have negligible effect on the rate of flow.
5.
Leak Detector - A device for detecting and locating leaks, and
indicating the magnitude thereof.
6.
Tracer Gas - A gas that, passing through a leak, can then be
detected by a specific leak detector and thus disclose the presence of
a leak. Also called search gas .
7.
Probe Gas - A tracer gas which issues from a more-or-less fine
orifice so as to impinge on a restricted test area.
8.
Pressure Testing - A leak detecting procedure in which tracer gas is
introduced under pressure into the enclosure under examination, and
detected as it is emitted from a leak.
9.
Soap Bubble Test - A type of pressure testing in which the tracer gas
is detected by bubbles formed in a layer of soap solution applied to
the surface of the test object.
1109-186-00 Rev. C a-i