INFICON UL1000 Helium leak detector - Manual (Page 9)

General Information
9
iina
70
e 0
1
.f
m
te
chn
ica
l ha
nd
boo
k
(1
40
8)
Auto zero
Measurement and automatic adaptation to the helium background.
This function determines the internal ZERO level of the unit which is then deducted
from the currently measured leak rate signal. This function is enabled by pressing
the Start key provided the UL1000 or UL1000 Fab have run at least 20 s in "Standby"
mode or in "Ventilation" mode.
If the before suppressed helium background further decreases and only the display
limit appears, the ZERO-level will be adjusted automatically
Menu
The menu allows the user to program the UL1000 and UL1000 Fab according to his
requirements. The menu has a tree architecture.
Default
Status of the UL1000 and UL1000 Fab when supplied by the factory.
GROSS
GROSS is a measurement mode which allows high inlet pressure (1 to 15 mbar).
The smallest detectable leak rate is 1x10
-6
mbar l/s.
FINE
FINE is the medium measurement mode with inlet pressure between 2 and 0,4 mbar.
Detection limit is 1x10
-10
mbar l/s.
ULTRA
ULTRA is the most sensitive measuring range with inlet pressures below 0,4 mbar.
The minimum detectable leak rate is 5x10
-12
mbar l/s.
Foreline pressure
Pressure in the foreline between Turbo pump and scroll pump.
Minimum detectable leak rate
The smallest leak rate the UL1000 and UL1000 Fab is able to detect
(
 5x10 -12
mbar l/s).
Internal helium background
The existing helium partial pressure in the measurement system. The level of the
internal helium background is measured in the Stand-by mode and subtracted from
the measured signal.
Measure Measurement mode
The UL1000 and UL1000 Fab measures the leak rate of the test sample.