Pfeiffer Vacuum QMA 125 User manual

Operating Instructions
BG 805 988 BE (2004-04) 1
Quadrupole Analyzer
QMA 125

2BG 805 988 BE (2004-04) QMA125.oi
In all communications with Pfeiffer Vacuum, please specify the information given on
the product nameplate.
This document applies to QMA 125, with Faraday cup or 90°off-axis SEM and
Faraday cup and the ion sources described below.
We reserve the right to make technical changes without prior notice.
The QMA 125 analyzers are designed for gas analysis in the high vacuum and ultra
high vacuum range. They are parts of the Pfeiffer Vacuum quadrupole mass spec-
trometry system and may be used only in connection with system components
defined for this purpose. The instructions in this user’s guide and in those of the
accessories must be conscientiously followed.
Product Identification
Validity
Intended Use

BG 805 988 BE (2004-04) QMA125.oi 3
Contents
Product Identification 2
Validity 2
Intended Use 2
1 Safety 5
1.1 Symbols Used 5
1.2 Personnel Qualifications 5
1.3 General Safety Instructions 5
1.4 Liability and Warranty 6
1.5 Training 6
2 Description 7
2.1 System Structure 7
2.2 Ion Sources 7
2.2.1 Axial Beam Ion Source 8
2.2.2 Gas-Tight Ion Source 9
2.2.3 UHV Grid Ion Source 9
2.2.4 Crossbeam Ion Source 9
2.2.5 Cathode Materials 10
2.3 Mass Filter 10
2.4 Ion Detectors 11
2.4.1 Faraday Cup 11
2.4.2 C-SEM 11
2.4.3 SEM 217 Secondary Electron Multiplier With Discrete Dynodes 12
2.4.4 Ion Deflection Unit (For SEM 90° Operation) 13
3 Technical Data 14
4 Installation 16
4.1 Preparation 16
4.2 Installing the Analyzer 17
4.2.1 Mounting Orientation 17
4.3 EP 422 19
4.4 CP 400 19
4.4.1 Removing / Installing the SEM Connector Plate 19
4.5 Electrical Connections 19
5 Start Up 22
5.1 First Time operation 22
5.1.1 Operation With Faraday cup 22
5.1.2 Operation With the C-SEM or SEM 23
5.2 Settings 23
5.2.1 Axial Beam Ion Source (Also Applies to Gas-Tight Version) 24
5.2.2 Grid Ion Source 25
5.2.3 Crossbeam Ion Source 25
5.2.4 C-SEM 26
5.2.5 Analyzer With 90°Off-Axis SEM 26
5.2.6 DEGAS Mode 27
5.3 Operating - and Bakeout Temperatures 27
6 Maintenance 28
6.1 General 28
6.2 Removing and Cleaning the Ion Sources 29
6.2.1 Mounting Tool 30
6.2.2 Axial Beam Ion Source (Also Applies to Gas-Tight Version) 31
6.2.3 Grid Ion Source 32
6.2.4 Crossbeam Ion Source 33
6.3 Removing and Cleaning the Mass Filter 33
6.3.1 Analyzer With Faraday Cup 33
6.3.2 Analyzer With C-SEM 34
6.3.3 Analyzer With 90° SEM 35
6.3.4 Taking Apart the Mass Filter 36
6.3.5 Cleaning the Rod System 37
6.3.6 Cleaning the C-SEM 37
6.3.7 Cleaning the SEM 217 37
7 Repair 38
7.1 Replacing the Filament 39
7.1.1 Axial Beam Ion Source (Also Applies to Gas-Tight Version) 39

4BG 805 988 BE (2004-04) QMA125.oi
7.1.2 Grid Ion Source 39
7.1.3 Crossbeam Ion Source 40
7.2 Replacing the SEM 217 / C-SEM 41
7.2.1 SEM 217 41
7.2.2 C-SEM 42
7.3 Removing the Connector Housing 42
7.3.1 All Connector Housings Except the Housing for the SEM 217 42
7.3.2 Connector Housing for the 90° off-axis SEM 217 43
7.3.3 Connector Housing SEM 43
7.4 Checks to be Made After Maintenance Work on the Analyzer 43
8 Accessories 44
9 Spare Parts 44
10 Storage 44
11 Returning the Product 45
12 Disposal 45
13 Anhang 45
A: Literatur 45
B: Electrical Connections and Pin Assignment 46
Declaration of Contamination 50
For cross-references within this document, the symbol (→XY) is used, for cross-
references to further documents, listed under literature, the symbol (→[Z]).

BG 805 988 BE (2004-04) QMA125.oi 5
1 Safety
DANGER
Information on preventing any kind of physical injury.
WARNING
Information on preventing extensive equipment and environmental damage.
Caution
Information on correct handling or use. Disregard can lead to malfunctions or mi-
nor equipment damage.
Skilled personnel
All work described in this document may only be carried out by persons who
have suitable technical training and the necessary experience or who have been
instructed by the operator of the product.
• Adhere to the applicable regulations and take the necessary precautions for the
process media used.
Consider possible reactions between the materials (→10, 15) and the pro-
cess media.
Consider possible reactions (e.g. explosion) of the process media due to the
heat generated by the product.
• Adhere to the forwarding regulations and prescriptions of the countries and
forwarding agencies concerned and attach the necessary warning labels in the
appropriate places.
• In case of toxic or explosive gases being measured by the QMA125, exhaust
gases have to be treated according to the regulations.
• Adhere to the applicable regulations and take the necessary precautions for all
work you are going to do and consider the safety instructions in this document.
• The instructions in the user’s guides of all system components must be con-
scientiously followed.
• Before beginning to work, find out whether any vacuum components are con-
taminated. Adhere to the relevant regulations and take the necessary precau-
tions when handling contaminated parts.
• Communicate the safety instructions to all other users.
1.1 Symbols Used
1.2 Personnel
Qualifications
1.3 General Safety
Instructions
Process media
Safety measures

6BG 805 988 BE (2004-04) QMA125.oi
Pfeiffer Vacuum assumes no liability and the warranty becomes null and void if the
operator or third parties
• disregard the information in this document
• use the product in a non-conforming manner
• make any kind of changes (modifications, alterations etc.) to the product
• use the product with accessories not listed in the corresponding product docu-
mentation.
The end-user assumes the responsibility in conjunction with the process media
used.
Caution
Caution: Inappropriate use
Inappropriate use leads to contamination and/or damage of the cath-
ode or the secondary electron multiplier.
Adhere to the instructions in this document in order to avoid damages
not covered by liability and warranty.
Training
Pfeiffer Vacuum offers application, operating and maintenance courses for the
best use of this product. Please contact your local Pfeiffer Vacuum representa-
tive.
1.4 Liability and Warranty
1.5 Training

BG 805 988 BE (2004-04) QMA125.oi 7
2 Description
A quadrupole analyzer consists of:
• Ion source
• Rod system (mass filter)
• Ion detector (cup)
• Connector housing
• Ion deflection unit 1)
EP controller
CC 125
SEM or
C-SEM
QMA 125
QME 125
EP 422
Controller
QMS 422
EP
Ion source Mass filter (90°-Ion-
deflection
unit) 1)
Faraday collector
Ion source
supply
IS 125 RF-generator
RF 125
High-
voltage
supply
HV 125
1) For optional SEM 90° operation
All the ion sources contain the following elements:
• One or two electron sources con-
sisting of a filament (1), a device to
accelerate (3), focus (2) and collect
the emitted electrons
• An appropriate ion optics system that
focusses the ions formed in the for-
mation chamber so that they enter
the mass filter (7)
1
2
3
7
The following types of ion sources are available:
• Axial beam-ion source
• Gas-tight model of the-axial beam ion source
• UHV grid-ion source
• Crossbeam-ion source
Ions are formed in collisions between the electrons emitted by the filament and the
molecules in the gas mixture being analyzed.
2.1 System Structure
2.2 Ion Sources
General

8BG 805 988 BE (2004-04) QMA125.oi
All the ion sources suited for use in the QMA 125 analyzer feature the following:
• The voltage between the formation chamber and the mass analyzer entry ap-
erture (ground) is higher than that between the formation chamber and the fila-
ment. This arrangement also results in the filament being at a positive potential
with reference to ground. To assure that the ions in the mass filter can be de-
celerated to the required low energy of several eV, the axis potential of the
mass filter may only be a few volts lower than that of the formation chamber.
This type of arrangement is advantageous from two points of view:
• No electrons are emitted into the environment where they could cause interfer-
ence to other units.
• The ions pass through the deleterious transitional fields between the grounded
entry aperture and the mass filter fast enough to minimize the effect of these
fields.
The illustration shows the basic design
of an axial beam ion source.
The acceleration voltage between the
filament emitting the electrons (1) and
the ionization chamber through which
the electrons flow (4) is ≈100 V. The
Wehnelt electrode (ground potential)
directs the electron flow in the ionization
chamber. In the formation chamber the
electrons collide with the gas molecules
present, forming ions. The formation
chamber is at 150 V. The grounded
entry aperture extracts the ions thus
formed and directs them into the mass
filter.
Three types of filament are available:
• Rhenium (Re), tungsten (W) and
yttria oxide iridium (YOx-Ir).
1
4
2
5
3
This type of ion source supplies ions with narrow energy distribution and low ve-
locity components perpendicular to the axis, which achieves good resolution and
high sensitivity with that particular mass filter. This is a result of the strong collima-
tion of the electron beam. The disadvantage of this arrangement is the high elec-
tron space charge which can cause non linear behavior at pressures in the
10−5mbar range. Lower emission is indicated if this should be avoided.
The relatively open design of this ion source guarantees low error of measurement
caused by self-degassing and surface reactions.
2.2.1 Axial Beam Ion Source

BG 805 988 BE (2004-04) QMA125.oi 9
The design of the gas-tight ion source corresponds closely to that of the axial beam
ion source. In the gas-tight source the grid is placed over a smaller aperture to
allow entry of the electrons. The gas to be analyzed is fed directly into the ion
source formation chamber (4) via a metal capillary at ground potential (6) and an
insulating intermediate piece (5). Two ceramic rings (7) and a disk (3) are used as
the sealing elements. Conductance is ≈1 l/s. The filament is outside the sealed
chamber in an area of high conductance where it interferes little with the gas to be
analyzed.
4
3
56
7
The open design of this ion source is
especially suited for residual gas analy-
sis in ultra high vacuum.
The selection of the construction materi-
als used, its design and the degassing
possibilities it offers through electron
bombardment result in very low outgas-
sing and desorption rates during opera-
tion.
The electrons emitted by the ring ca-
thode (2) are accelerated to the grid (1).
The ions formed through collisions with
electrons inside the grid area are ex-
tracted through the grounded mass filter
entry aperture and into the mass filter
through the central aperture opening.
The filament is divided into two parts
with a center contact.
The filament is made of tungsten (W).
2
1
The cross beam ion source has two filaments that can be operated one at a time as
required. They allow the direct entry of molecular beams perpendicular and parallel
to the system axis. It is highly linear. Compared to the axial beam ion source, how-
ever, its sensitivity is lower.
2.2.2 Gas-Tight Ion Source
2.2.3 UHV Grid Ion Source
2.2.4 Crossbeam Ion Source

10 BG 805 988 BE (2004-04) QMA125.oi
The electrons emitted by one of the two
filaments (1) are accelerated into the
formation chamber (2) perpenticular to
the system axis. The emitted electrons
are collimated by the Wehnelt electrode
(3) mounted on the filament block and
connected to the filament at one end.
The extraction aperture (4) generates a
weak electrical field in the formation
chamber which is used to extract the
ions. The lens (5) focusses the ions into
the rod system. The design of the ion
source does not allow it to be operated
at fixed voltages applied to the extrac-
tion aperture and the ion optics i.e. the
applied voltages must be continuously
adjustable (→25).
Three types of filaments are available:
• Rhenium (Re), tungsten (W) and
yttria oxide iridium (YOx-Ir).
2
3
1
4
5
The ion sources can be equipped with cathodes (filaments) which are best suited
for the planned application. Certain cathode materials are not available for all
source types (→44).
In contrast to tungsten, rhenium does not form any stable carbides, since no CO2
cycle as known with W takes place. In addition, Re is not embrittled by recrys-
tallization.
The vapor pressure of Re is approximately 50 times higher than that of W, and the
filament life is accordingly shorter. Getter effects may occur due to the evaporation.
Tungsten is used when the higher vapor pressure of Re is undesirable, when a
long filament life is required, or when the advantages of Re are not important to the
application.
Since yttria oxide iridium does not form oxides, it is quite insensitive to air inrushes.
The emission temperature of yttria oxide iridium filaments is lower than that of Re
and W filaments. Reactions with residual gas are weaker because the ion source
temperature remains low.
The contamination may be stronger in the presence of substances with a low vapor
pressure.
The mass filter consists of four cylindrical rods. They must be precisely aligned for
proper functioning (mass separation, stability, and sensitivity). An adjustable radio
frequency voltage and a superposed DC voltage proportional to it are applied to the
rod system. The trajectories of the ions in the electrical field inside the rod system
are dependent on the m/e (mass/charge) ratio of the particular ion. Only ions of one
specific m/e ration reach the detector while all other ions are filtered out.
2.2.5 Cathode Materials
Rhenium (Re)
Tungsten (W)
Yttria oxide Iridium (YO
x
-Ir)
2.3 Mass Filter

BG 805 988 BE (2004-04) QMA125.oi 11
ro
y
x
z
–(U + V cos ωt)
+ (U + V cos ωt)
Field axis
The ion detector can be a simple Faraday cup or, for sensitive measurements, a
SEM (Secondary Electron Multiplier) or a C-SEM (Continuous Dynode Secondary
Electron Multiplier).
The ions impinging on the Faraday cup produce an electrical current which is
measured directly by the electrometer preamplifier.
The SEM and C-SEM have the function of considerably amplifying that electron
current.
Two types of SEM are available:
• C-SEM with integrated deflection system
• SEM with 17 discrete stages and 90° deflection system
Both SEM versions also contain a Faraday cup, and operation can be changed to it
whenever necessary during operation.
The only type of minor errors that occur with this detector are system-related. Its
disadvantage is its low sensitivity. This requires high amplification which limits the
response speed. In the simplest version the electrometer amplifier is connected
directly, meaning that the ion current is conducted directly into the amplifier.
The C-SEM is a bent glass tube, the inside surface of which has a defined, low
electrical conductance. If a voltage is applied between the two ends of the tube, a
current is generated that causes a constant voltage drop, making the surface a
type of continuous dynode. The principle of operation is similar to that of the SEM
with discrete dynodes and chain of resistance (→12).
An advantage of the C-SEM compared to the discrete SEM is that it is largely not
sensitive to repeated ventings as long as certain precautionary measures are
taken. Its disadvantage is its high sensitivity to current overload.(→26).
2.4 Ion Detectors
General
2.4.1 Faraday Cup
2.4.2 C-SEM
Design Principle

12 BG 805 988 BE (2004-04) QMA125.oi
If an ion, electron, photon or fast neutral
particle hits the entry channel of the C-SEM,
electrons are released from its surface.
These are accelerated by the electrical field
and, because of the bend in the tube, hit the
surface again further on where they release
secondary electrons. This process is re-
peated several times causing cascade-type
in-crease in the number of electrons down to
the positive end of the C-SEM. Thus the C-
SEM reacts to the impingement of a single
particle with a charge pulse that can contain
up to 108electrons. The gain is exponential
and thus a very steep function of the voltage
applied, as long as that gain is under 107.
Above this, saturation effects occur which
are chiefly caused by space charges that
limit the gain produced by the C-SEM to
approx. 108. The C-SEM used is chosen for
increased linearity and long lifetime at the
cost of extremely high gain.
HV
+−
Mass filter
Faraday-cup
Electrometer
This detector features very high gain and
fast response time.
The ions impinging on the first "dynode"
(conversion dynode) release electrons from
its surface. These are accelerated to the
next dynode (D2) where they release addi-
tional secondary electrons. When the yield
is higher than 1, the number of electrons
increases in a cascade up to dynode 17.
After dynode 17, the electrons hit the cup.
The electron current thus produced is
measured by the electrometer preamplifier.
Because the current measured by the SEM
is several powers of ten higher than that
measured by a Faraday cup under the same
conditions, a lower amplifier sensitivity
setting can be used when working with the
SEM. In this latter case, the amplifiers re-
sponse time will be considerably faster.
SEM
D1
D2
D3
D4
D16
D17
R1
R2
R3
R4
R16
R17
R18
+
Electrometer
0 … –3kV
C
C
–
+
Mass filter
HV–
Cup
Connection
plate
Principle of Operation
2.4.3 SEM 217 Secondary
Electron Multiplier With
Discrete Dynodes

BG 805 988 BE (2004-04) QMA125.oi 13
The detection capability of the SEM is a
function of the number of electrons re-
leased from the conversion dynode per
impinging ion. The total gain, in contrast, is
determined chiefly by the secondary elec-
tron rate of the individual dynodes. Both
these rates are to a large extent a function
of the dynode surface structure. The en-
ergy is mainly determined by the applied
operating voltage and the kinetic energy of
the impinging particle. Thus the gain can
be adjusted within a wide range according
to the applied voltage. Some characteris-
tics of the impinging particles (charge,
mass, chemical nature) also have an influ-
ence on the conversion rate. 200100 Dynode voltage (V)
Gain
103
104
105
106
107
108
109
The main disadvantage of the SEM is that its function is highly dependent on qual-
ity of the dynode surfaces, which can change during operation by a number of
factors.
Not only ions impinging on the conversion dynode release electrons, but also fast
neutral particles, excited neutral particles and photons. These particles are not held
back by the mass filter, and would cause background noise at the detector, which
would considerably reduce its detection capability. To separate these out, the ions
exiting the mass filter are deflected 90° to the conversion dynode while the other
particles continue on straight ahead. The remaining background noise is then
chiefly due to the SEM dark current.
The deflection capacitor (2a, 2b) is at-
tached to the tube (5) with cylinder head
screws (4), and the tube is attached to
the flange (3) with hex screws (6). At the
other end the mass filter (1), with its out-
side cover, is attached. There are
threaded connections (7) at the output of
the deflector capacitor (2a, 2b) to which
the shielding tube for the SEM is at-
tached. This tube (5) contains two
square apertures that must be closed
with a springloaded cover.
1
4
3
5
6
2b
2a 7
7
For the detection of positive ions, the smaller deflection plate (2a) is placed on
negative potential (deflection) while the larger plate (2b) is on ground potential.
If the measurement is to be made in Faraday mode, connect the amplifier to the
outer deflection plate (central connector). The deflection voltage is disconnected.
2.4.4 Ion Deflection Unit
(For SEM 90° Operation)

14 BG 805 988 BE (2004-04) QMA125.oi
3 Technical Data
Admissible overpressure (absolute) ≤2 bar (absolute)
Operating pressure
with Faraday
with SEM ≤1×10−4mbar
≤1×10−5mbar
Lowest detectable partial pressure
without SEM
C-SEM
with 90° off-axis SEM and ion
counter electronics
3×10−11 mbar
5×10−14 mbar
5×10−14 mbar
Sensitivity for Argon 1)
without SEM
C-SEM
with 90° off-axis SEM
2×10−4A/mbar
>100 A/mbar
>1000 A/mbar
For bakeout temperatures >150 °C, the connector housing has to be
removed.
with SEM 90° without SEM C-SEM
with connector housing
without connector housing ≤150 °C
≤400 °C
≤150 °C
≤300 °C
≤150 °C
≤300 °C
without SEM
with SEM 90°
C-SEM
300 °C2)
150 °C2)
100 °C2)
Axial beam "Gas-tight" Grid Crossbeam
Emission current
Degas
Filaments
quantity
material3)
0.1 …1 mA
1
Re, W, YOx-Ir
0.1 …1 mA
1
Re, W, YOx-Ir
0.1 …1 mA
2 …20 mA
2
W
0.1 …1 mA
2
Re, W, YOx-Ir
1) At IE =1 mA, unit resolution, axial ion source and QME 125-1
2) Caution: Connector housing ≤150 °C
3) material: Re = rhenium, W = tungsten, YOX-Ir = yttria oxide iridium
Overpressure
Vacuum
Sensitivity
Bakeout Temperatures
Operating Tempertures
Ion Sources

BG 805 988 BE (2004-04) QMA125.oi 15
Dimensions
rod diameter
rod system, length
field radius
Material
rods
holder
Installation opening
ø6 mm
100 mm
ø2.6 mm
stainless steel
glass ceramic
≈ø30 mm
C-SEM SEM 90°
Gain typ. at >2500 V
Admissible current
Sensitivity 4)
Number of stages
Dynode material
Voltage divider MΩ/ stage
106
10-6 A
1×10−4A/mbar
>106
10-5 A
1×10−4A/mbar
17
Cu/Be
1
QMA 125 with SEM 90° off - axis
112 157.5
ø74
DN 40 CF-F
53 *
QMA 125 with
C-SEM
QMA 125
ø74
107 123.5 *
DN 40 CF-F
147
309
DN 63 CF-F
105 (140) 53.5
105
ø60
*
ø74
*Axial beam ion source 30.5 mm
Grid ion source 29 mm
Cross beam ion source 18.6 mm (10 mm to the middle of the sensitive volume)
Gas-tight ion source 30.5 mm (10 mm to the gas connection)
Housing, flanges stainless steel
Feedthroughs ceramic
without SEM 900 g
with SEM 90° 8400 g
C-SEM 3700 g
4) For axial beam ion source, QME 125-1, unit resolution
Mass Filter
C-SEM, SEM 90°
Dimensions
Materials
Weights

16 BG 805 988 BE (2004-04) QMA125.oi
4 Installation
DANGER
Caution: hazardous electrical voltages
Hazardous voltages up to 600 V are applied to the QMA 125.
Make sure the QMA, the vacuum chamber, and the whole system are
always correctly connected to ground.
If accidental contact to the QMA is possible when the vacuum system
is opened, additional protective measures have to be taken, for in-
stance:
• Mechanical protection against accidental contact
• Forced disconnection of the QMS 422 from the mains power
source through door contact.
DANGER
Caution: hazardous electrical voltages
Under unfavorable conditions (arcs, plasma, vacuum problems), volt-
ages up to 600 V can be fed to other equipment in the vacuum cham-
ber (e.g. gauges).
If there is a possibility that such pieces of equipment become sources
of shock hazard (consider also the conductors and connected equip-
ment!) they must be arranged or protected in such a way that any risk
of accidental contact, arcs, or flow of charged particles is excluded.
DANGER
Caution: hazardous external voltages
Under unfavorable conditions (arcs, plasma, vacuum problems), volt-
ages of other equipment installed in the vacuum system (e.g. ioni-
zation gauges, plasma sources, electron beam evaporators etc.) can
be supplied to the QMA 125. Open connectors, connected equipment
and cables are potential sources of shock hazard.
If there are such potential sources of shock hazard in the vacuum
system, protective measures have to be taken (layout, grounding,
shielding etc.) to prevent such influences.
• 2.5 mm2if mechanically protected (according to
DIN VDE 110 T540)
• 4.0 mm2if not mechanically protected
Consider the specific standards of your system.
DANGER
Danger: hazardous gases
Process gases can be detrimental to health.
Before admitting the process gas, check that the connection is leak
tight.
Make sure the exhaust system is suited for the admitted gases.
4.1 Preparation

BG 805 988 BE (2004-04) QMA125.oi 17
Caution
Caution: vacuum component
Dirt and damages impair the function of the vacuum component.
When handling vacuum components, take appropriate measures to
ensure cleanliness and prevent damages.
Caution
Caution: dirt sensitive area
Touching the product or parts thereof with bare hands increases the
desorption rate.
Always wear clean, lint-free gloves and use clean tools when working
in this area.
The analyzer comes supplied with the requested ion source and is ready for op-
eration.
The analyzer can be installed at any angle required by the user's vacuum chamber.
Note, however, that the position chosen must fulfill vacuum and measurement
technological requirements. For example, for a true, reliable residual gas meas-
urement the analyzer should not be connected via a narrow-diameter tube to the
vacuum chamber under study.
Each QMA 125 analyzer is supplied with a bracket which allows the QME125
mass filter electronics to be mounted to the QMA connection flange (→[1]).
Analyzers without SEM's have a
DN 40 (35) KF flange. They are supplied
in a Plexiglas tube to protect them from
mechanical damage.
Flange
Connector housing Protection tube
Store the transport safety devices and re-install them before trans-
porting the product.
When inserting the analyzer through the vacuum chamber flange,
take care that the wiring is not damaged (danger of short circuit).
4.2 Installing the Analyzer
4.2.1 Mounting Orientation
Analyzer Without SEM

18 BG 805 988 BE (2004-04) QMA125.oi
This analyzer has a DN 63 CF flange (flange 2). It has to be operated in the
T-shaped housing, unless there is no SEM required for the application.
It is supplied under vacuum in a sealed protection tube, which should not be re-
moved until shortly before the analyzer is installed.
Protection tubeHousingConnector housing 1
Flange 1
Flange 3
SEM
Flange 2
Connector housing 2
Store the transport
safety devices and
re-install them be-
fore transporting
the product.
This system is mounted on a
DN 63 CF (1) flange. Its housing is a
reduction piece with a DN 40 CF
flange (2). The analyzer can be
mounted using flange 1 or 2.
Flange 2Flange 1
Protection tube
Store the transport safety devices and re-install them before trans-
porting the product.
With this analyzer the test gas is ad-
mitted to the ion source via a separate
gas transfer line. Usually this line is not
attached to the analyzer until the ana-
lyzer has been properly installed. The-
refore, when setting up your equip-
ment, be sure to leave yourself access
to the analyzer for connecting the line.
When making the connection, be sure
to use an insulator sleeve.
The gas line must be electrically insulated from the ion source to main-
tain the proper operating conditions for the source.
Store the transport safety devices and re-install them before trans-
porting the product.
Analyzer With 90° SEM
Analyzer With C-SEM
Analyzer With Gas-Tight Ion
Source

BG 805 988 BE (2004-04) QMA125.oi 19
Connect the electrometer preamplifier EP 422 to the Faraday cup connector
EP (FARAD) on the QMA if applicable (→2).
Mount the second electrometer preamplifier EP 422 to the SEM cup connector
EP (SEM) if applicable (→2).
Install the ion counter preamplifier CP 400 if applicable (→2).
Before installing the CP 400 remove the SEM connector plate of the QMA or the
cover if it is equipped with a SEM connector plate.
Turn the equipment off and disconnect the EP 422 and cables from the connector
plate.
• Remove the two big screws.
• Remove the protective tube.
• Remove the three screws.
• Unfasten the three hex socket
screws (size 1.5 mm) by ½ turn.
• Detach the cable lug of the yel-
low/green ground conductor from the
flange.
• Detach the connector plate.
• Unscrew the three studs using
a suitable pin.
The details of the electrical connections between the analyzer QMA125 and the
QME 125 depend on the analyzer being used and the application for which it is
intended. The following table gives all feasible configurations.
DANGER
Caution: hazardous electrical voltages
The voltages under the connector plates are extremely hazardous.
Before installing the cables mount all protective tubes.
4.3 EP 422
4.4 CP 400
4.4.1 Removing / Installing the
SEM Connector Plate
4.5 Electrical Connections
Mounting the Protective Tubes

20 BG 805 988 BE (2004-04) QMA125.oi
Cable Length [m] Ordering number.
1 Connection QMS - QME 3 BG448167-T
2 Extension QMS - QME 10 BG448197-T
3 Extension QMS - QME 20 BG448170-T
4 RF/ion source (QMA) 0.17 mounted on QME 125
5 Electrometer supply 0.6 mounted on EP 422
8 High voltage 0.3 BG448083-T
9 High voltage 0.7 BG548996-T
10 Protection ground 0.3 mounted on QME 125
Analyzer with Faraday cup
(Faraday operation) Analyzer with C-SEM (SEM operation)
QMS
QME
QME 125
HV– QMA
1 2 3
4
5
EP
EP 422
10
1)
QMS
QME
QME 125
HV–
EP
QMA
1 2 3
4
HV- 8
EP 422 5
10
1)
SEM operation Faraday operation
EP
HV–
QMS
QME
QME 125
HV– QMA
1 2 3
4
9
EP 422
HV+
5
10
1)
Shorting
connector
Shorting
connector
EP
HV+
HV–
QMS
QME
QME 125
HV– QMA
1 2 3
4
EP 422
5
10
1)
Shorting
connector
Shorting
connector
1) Ground connection at the clamping ring of the QME125 (→[1]).
Identifying the Cables
Analyzer With Faraday Cup
and With C-SEM
Analyzer With 90° SEM