For a leak detector to give
reliable, repeatable results it is essential that it always performs at its
optimum. The Spectron 600 incorporates several features designed to make it the
most accurate leak detector available.
Auto Tune Alert
Auto
Tune Alert
The Auto Tune Alert reminds
the user to tune the unit every 50 hours of use. Alternatively, the user can
select Automatic Auto Tune, and every time the unit is switched on it performs
an automatic tuning cycle as part of the start-up process. During the tuning
cycle, voltages applied to the mass spectrometer are adjusted and optimized for
peak sensitivity and performance.
Calibration Check
When testing components with a
specified maximum leak rate or if the unit is in use for extended periods, it
is advisable to periodically check that it is calibrated to the internal
reference leak. Pressing the CAL CHECK button does this. The unit then performs
an independent calibration check without forcing an automatic re-tune cycle.
The operator can then decide whether to accept, re-calibrate or re-tune.
Competitive models
automatically re-tune, giving no option to view the calibration value, which
creates uncertainty with respect to prior tests.
One-button Auto Tune and
Calibration
If the operator decides to
re-tune the unit, he/she presses the TUNE button. The calibrator valve opens to
the mass spectrometer and the anode, filament DC, focus plates, grid and repeller
voltages are automatically tuned. The calibrator valve closes and the amplifier
offset and system background is recorded. The calibrator valve opens, the
variables are subtracted and the amplifier gain adjusted to the temperature
compensated calibrator value.
Internal Calibrator
The Spectron 600 has a
built-in helium 4 calibrated leak, which delivers a specified leak in the range
1 x 10-8 to 3 x 10-8 mbar ls-1 air equivalent.
Because leak rates change ± 3.3% ºC-1, the reference leak is
temperature compensated and (to aid compliance with ISO-9000 and quality
control procedures) it is traceable to NIST (US national standards
organization, National Institute of Standards and Technology).
We recommend that the leak is
re-calibrated once a year and there is quick disconnect for changing
re-certified calibrators.
Mass Spectrometer
Two
identical magnetic fields (90° sectors) are used in the Spectron 600’s mass
spectrometer to make sure that only helium ions reach the ion collector. This
is a unique feature, which gives the Spectron 600 a resolution (the ability of
a mass spectrometer to separate ions of different mass/ charge ratios), of 14 -
almost twice that of competing models.