| |
UHV Pressure
Gauge Controller NGC2 (Vakuum Meß- und
Steuersystem NGC2
Paket)
AML's NGC2 UHV
Bayard-Alpert controller is a low-cost instrument which includes
facilities
for Pirani gauges, capacitance
manometers, relays, logging through a serial interface and a large
number
of safety features. Operation is very simple, so that casual users do
not
need to consult manuals.
AML's NGC2 UHV
BA controller has improved performance compared to PGC1 and PGC2, which
it replaces. In 98% of cases it is a direct, plug-in replacement. It
has
longer, brighter LED display. All functions and setup are available
from
the front panel. Two fans are fitted, used alternately and monitored
for
perpormance.
- 1U high full-width,
steel-cased instrument for easy rack-mounting. Operates on
100 to
240v, 50/60Hz lines without adjustment.
- Controls 1 BA gauge
plus 2 AML Pirani gauges plus a Capacitance Manometer simultaneously.
- Continuous measurement
range: 1 bar to 3 x 10-11 millibar.
- AML and approved
equivalent gaugeheads may be exchanged or lead lengths altered without
adjustment. Many other BA gauges are suitable
- Filament current
limit automatically set for filament material. Filament in use selected
from the front panel. Ion gauge is grounded when not
operating.
- Variable BA gauge
sensitivity.
- Reduced emission
current. Instrument advises optimum emission current at low
pressure.
- Automatic start
of BA gauge in pump-down.
- BA gauge interlock
by Pirani or external signal (contact closure).
- Electron-bombardment
degas program with independent adjustment of ramp, power and dwell
time.
Variable "quick" degas program with ramped start. Manual
degas.
Excessive or inappropriate degas is limited or inhibited.
- Pirani gauges may
be switched on or off from the front panel.
- Comprehensive temperature
management, with early indication of the need to replace a fan. Failure
of a single fan does not inhibit use.
|
- Bright green LED
display shows bargraph or numeric pressure, trend, diagnostics,
etc..
Display in mBar, Torr or Pascal. Permanent bargraph of Pirani
pressures.
- Simple, guided-setup
is re-entrant and divided by function. Setup can be
password-protected.
- Preset adjustable
bakeout program with control of temperature, time and overpressure
limit.
Integral K-thermocouple amplifier.
- Automatic control
of sublimation pump with countdown/cancellation of imminent firing.
- Integral, variable-sensitivity
leak detector with audio output on Pirani1 or ion gauge.
- 4 internal power
relays (5A, 240V) flexibly- assignable to gauges from the front
panel.
All external relay wiring is connected through a pluggable screw
terminal
block, which has a retaining safety shield.
- Non-volatile relay
setpoints with manual override and inhibit facility. Simple
setpoint
adjustment and interrogation while measuring pressure.
- RS232-compatible
interface for data-logging and control (cost - option).
- Recorder output
1.0 volt/decade on pluggable, 4-way screw terminal block with
capacitance
manometer and inhibit signals.
- Supplied with a
mains lead, relay and auxiliary connectors, spare fuse and brief user
manual.
- Cost-saving packages
including gauges, leads and extended warranty are available.
|
| Dimensions:
Net
weight: 3,5kg
Shipping weight:
5,0kg
Carton
dimensions: 60 x 40 x 13cm
|
 |
BAYARD
ALPERT GAUGE
| Types: |
AML
AIG17G is recommended. BA gauges
from many other manufacturers are suitable, without adjustment other
than
sensitivity. A list of tested and approved gauges is
available from
AML. The use of non-approved gauges and leads may result in unstable
emission
or non-compliance with EU legal requirements and is not covered by
AML's
warranty. |
| Range: |
From 1
x 10-3 to below 3 x
10-11 mB with a UHV gaugehead with tungsten
filaments. The low
limit is dependent on gaugehead, cable construction and length and
conditions
of use. The upper limit is determined by the acceptable life
of the
filament and may be extended by the use of thoria or yttria-coated
iridium
filaments. |
Accuracy and
Repeatability: |
Determined
principally by the gaugehead:
controller errors are much smaller. Emission at 0.5mA is
recommended.
Electrometer
logarithmic conformance <1%
within any decade from 0.1 mA to 10 pA, <5% to 1 mA and
<20% to 2
pA at 25ºC incoming air temperature. Slope
temperature compensation
<0.02% per degree Celsius. Differential linearity of
the 12- bit
A to D converter is less than 0.1 LSB. Emission current
initial accuracy
<2%, stability <1%. |
| Gauge Supplies: |
Grid:
+200 volts in emission, +500 volts
at <60 mA in degas.
Filament: +50
volt bias, <12 volts
at <4.2 A (Tungsten) <2.6 A (Yttria) with
filament power limited
at > 30 watts. |
Full
Specifications of AIG17G Bayard-Alpert
Gauge here
CAPACITANCE
MANOMETER ( CM )
Capacitance
Manometers of any manufacture
having a +10 volt full-scale output at 1, 10, 100 or 1000 Torr or
millibar
and which are self-powered are suitable. Pressure indication
can
be in units different to the full-scale units defined for the
Capacitance
Manometer.
PIRANI
GAUGES.
AML types PVU2
and PVB2. A constant-voltage
bridge circuit reduces contamination at high pressures. AML
Pirani
gaugeheads may be exchanged or extension leads may be connected without
adjustments being necessary.
Details see here
GENERAL
| Pressure
Display: |
Scientific
notation with a 2-digit mantissa
for all gauges. Bargraph displays may be selected. |
| Operating Temperature: |
5º
to 35º Celsius for specified
performance. Incoming air temperature is measured and displayed and
operation
is inhibited at >40?C. |
| Supply
Voltage: |
100 V
to 240 V nominal at 48 to 65 Hz,
without adjustment. |
| Power
Consumption: |
<20
watts idling, <75watts
in emission. |
| EMC Compliance: |
Compliance
with EU EMC Directive 89/336/EEC
can only be guaranteed if AML BA gauge leads and screened Pirani gauges
are used. |
AML
pursues a policy of continuous product
improvement and reserves the right to make detail changes to
specifications
without consultation. Unless otherwise stated all specifications are
typical
and at 25º Celsius, after 1 hour operation. E and OE.
IMPROVED BAYARD-ALPERT
GAUGEHEADS AND LEADS FOR UHV.
MODELS
AIG17P, AI17G AND
AIGLx
AIG17P
AIG17G
AIGL3 and AIGL3P
Bayard-Alpert
Gaugeheads and leads for
Ultrahigh Vacuum.
AML BA gauges
and leads are widely acknowledged
as the best available in the industry. New-product
introductions
and enhancements confirm and extend this lead. The use of AML
double-screened
BA gauge leads is essential to ensure that AML Pressure Gauge
Controller
installations comply with EU EMC Directive.
- AIG17G
is a nude UHV Bayard-Alpert
gauge intended for electron-bombardment degas. It has an individual
glass
compression seal around each feedthrough pin. These glass seals are
more
economical and robust than ceramic, resulting in a less expensive and
more
rugged gaugehead, with the central collector pin inherently guarded
against
leakage currents by the grounded bulk of the flange. Twin tungsten
filaments
are standard. AML have improved the construction and method
of attachment
of the Molybdenum grid. The grid has a closed-end, light, rigid
structure,
resulting in high sensitivity. The X-Ray-induced electron desorption
current
at the collector is minimised by geometry and screening. The connector
pins are gold-plated, shrouded and polarized. Sensitivity is 19 per
millibar
for nitrogen. Sensitivity for other gases is tabulated
overleaf.
X-Ray asymptote is 3 x 10-11 millibar. Maximum bakeout temperature is
250°C.
Mounting flange is NW35CF.
- AIG17P
incorporates a Pirani gauge
on the same flange as the BA gauge. To use the Pirani gauge it must be
connected to the PGC with an AIGL3P lead. The use of this combination
gauge
leads to significant cost-saving and eliminates a port on the vacuum
chamber.
|
- FIL17is a replacement twin-tungsten
filament assembly. The assembly is held by Allen set screws
in socket receptacles and a key and replacement screws are provided.
- FIL18 is a
twin thoriated iridium filament which is
working at lower temperatures than tungsten filaments.
- FIL19
is a twin yttria-coated iridium filament assembly. Yttria is a safe and
equivalent alternative to the toxic and radioactive thoria formerly
used.
- AIGL3
is a 250°C-bakeable 3-metre
lead for use with AIG17G and similar ionisation gauges connected to AML
controllers. AIGL6 and AIGL9 are 6 and 9 metre versions. AML use
gold-plated
connectors exclusively: these are essential for reliable long-term
measurement
of the ion current after baking. The cable is rated for the worst-case
operating conditions of 50 watt degas with a new tungsten filament
during
a 200°C bake. This product uses an entirely PTFE-insulated
custom cable
and incorporates an overall electrical screen and fully screened and
guarded
collector with >1x1015? insulation. The connector housing is
machined from
PEEK and the cable clamp is a bright nickel-plated casting.
- AIGL3P
has an additional connector
incorporating calibration adjustments for the integral Pirani gauge on
AIG17P.
|
AIGL3
and
AIG17G |
 |
AIGLP
and
AIG17P |
 |
Recommended
Operating condition
|
Emission |
Degas |
| Collector |
+0V |
+0V |
| Grid |
+200V |
+500V |
| Filament bias |
+50V |
+0V |
| Maximum Emission
Current |
10mA |
100mA Tungsten
60mAThoriated |
These
bias conditions produce
sensitivity shown in the table below.
Sensitivity,
S, mBar-1
| H2O |
19 |
| O2 |
21 |
| H2 |
6.2 |
| He |
2.4 |
| Ar |
21 |
| N2 |
19 |
| CO |
19 |
| CO2 |
27 |
| Ne |
5.4 |
| CH4 |
27 |
Divide
S by 100 for Pa-1;
multiply by 1.33 for Torr-1.
Filament
Types
| Filament power varies over
the useful life of a filament, due to gradual erosion of bare tungsten
or loss of the oxide coating. In general, yttria-coated iridium
filaments
require about one quarter the power of tungsten at mid-life. Thoria is
radioactive, toxic and no longer recommended. Yttria has similar
properties
and runs less than 50°C hotter in normal emission. Yttria also
has
better adhesion and consequently longer life. Oxide-coated filaments
adsorb
water in storage and may require more power initially to evaporate it. |
The
filament power supply must be capable
of providing high currents to develop adequate power in the low
resistance
of a cold filament and sufficient voltage to compensate for drops in a
long, hot cable. A power-limited supply of 40 watts capable of
providing
up to 12 volts and up to 4 amps will drive any AIG17G gauge operating
under
any conditions, (including degassing during bakeout at 250°C)
with
an AIGL9 lead. AML BA gauge controllers exceed these requirements and
include
comprehensive filament protection features. |
PIRANI
GAUGEHEADS FOR ULTRAHIGH VACUUM
MODELS
PVU PVB
Aml produce a
range of Pirani gaugeheads
to complement their Pressure Gauge Controllers.
All models include an
integral lead for
convenience and economy in installation
Pirani Gauges
Pirani gauges
detect the cooling effect
of residual gas molecules on a heated filament. The rate of heat
transfer
to the gas is related to pressure and causes a change in the electrical
resistance of the filament or the amount of power required to maintain
it at constant temperature. The filament is normally connected in a
bridge
circuit.
General
Features of AML Pirani Gauges
- AML
Pirani gaugeheads are intended for use
in constant-voltage bridge circuits, which reduces the filament
temperature
and the rate of filament corrosion or contamination at high pressures.
- Range: 1
bar to 1 x 10-3 millibars.
- May be
interchanged between any AML PGC series
or equivalent controllers without re-calibration. Extension
cables
do not affect the calibration.
- Supplied
calibrated for vertical installation
in dry nitrogen. Internal calibration adjustments enable them
to
be used with other orientations and gases.
- Materials
exposed to the vacuum are stainless
steel, nickel-cobalt-iron, glass and tungsten.
Features
of specific AML Pirani Gauges
- PVU2 is a
low-cost non-bakeable gaugehead
with an integral 3-metre lead and connector. The feedthroughs
use
matched glass-to-metal seals which have better life and leak
performance
than the epoxy or compression seals used on other low-cost Pirani
gaugeheads.
The standard flange is NW16KF.
- PVB2 is a
UHV-compatible stainless-steel Pirani
gauge with an integral 3-metre lead and connector which can be baked at
250ºC. The standard flange is
NW16CF.
- PVX10 is
a 10 metre extension cable for use
with PVU2 or PVB2. These cables extend the Kelvin sensing of
AML
PGCs, so that the extension does not affect the calibration.
GAUGEHEAD DIMENSIONS / ORDERING INFORMATION
Gauges are
supplied calibrated for dry
nitrogen. Calibration instructions are supplied with all
gauges.
AML Pirani gauges are intended for use with AML Pressure gauge
controllers
and 1U-high controllers manufactured by AML for other
vendors. Such
controllers may be identified by the AML copyright marks on the printed
circuit boards.
For new
installations the use of combination
gauges will save cost and reduce the number of ports required.
|
