Terminology - Agilent Technologies 947 Betriebs- Und Servicehandbuch

Models 947, 948 and 960 Leak Detectors Operations and Service Manual
G.3 Terminology
The following terminology has application throughout this manual:
Flow
atm cc/sec
std cc/sec
Rate-of-Rise
Conversions
Numerical
Notation-Exponential System
G-2
One cubic centimeter of gas per second at a pressure differential
of one standard atmosphere (760 Torr at 0 °C).
One cubic centimeter of gas per second at ambient atmospheric
pressure and temperature (used interchangeably with atm cc/sec
because the difference is insignificant for leak testing purposes).
In vacuum systems this is defined as the rate of increase of
absolute pressure per unit time, with the vacuum pump isolated
from the system, and is the sum of actual inleakage and internal
outgassing. Rate of rise is usually expressed in Torr or microns
(milliTorr) per hour. The flow rate should be expressed in
Torr-liters/second.
1 std cc/sec* 0.76 Torr-liter/sec
1 Torr-liter sec*
1 std cc/sec9.7 x 10
1 µCFHpractically 10
*for practical purposes, equal
Most leak rates of commercial significance are very small fractions
of atm cc/sec. Therefore negative powers of ten are used as a
convenient system of numerical shorthand.
Table G-1 shows the relationship of exponents and
multipliers (to the base 10) to the arithmetic form, and the
equivalent result.
n
Multiplier x 10
2
1 x 10 =
1
1 x 10 =
0
1 x 10 =
-1
1 x 10 =
-2
1 x 10 =
-3
5 x 10 =
-7
5 x 10 =
-9
5 x 10 = 5 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10
1.3 std cc/sec
4
micron cubic feet per hour or
5
practically 10 micron CFH (µCFH)
−5
std cc/sec
Table G-1 Decimal Notation
Arithmetic Form
1 x 10 x 10
1 x 10
1
1 x 1/10
1 x 1/10 x 1/10
5 x 1/10 x 1/10 x 1/10
5 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10 x 1/10
Result
= 100
= 10
= 1
= .1
= .01
= .005
= .0000005
= .000000005