ISO 14291:2012

INTERNATIONAL ISO
STANDARD 14291
First edition
2012-07-15
Vacuum gauges — Definitions and
specifications for quadrupole mass
spectrometers
Manomètres à vide — Définitions et spécifications des spectromètres
de masse quadripolaires
Reference number
©
ISO 2012
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ii © ISO 2012 – All rights reserved

Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Terms and definitions . 1
2.1 Definitions of components. 1
2.2 Definitions of physical parameters . 5
3 Symbols and abbreviated terms . 8
4 Principle of QMS . 9
5 Specifications for a QMS to be provided by manufacturers . 9
5.1 Mass range . 9
5.2 Type of ion source . 9
5.3 Type of ion detector . 9
5.4 Mass resolution .10
5.5 Mass number stability .10
5.6 Sensitivity .10
5.7 Linear response range .10
5.8 Minimum detectable partial pressure .10
5.9 Minimum detectable concentration .10
5.10 Maximum operational pressure .10
5.11 Scanning parameter .10
5.12 Signal output . 11
5.13 Potentials . 11
5.14 Detector specifications . 11
5.15 Set point . 11
5.16 Maximum bake-out temperature . 11
5.17 Nominal operating conditions. 11
5.18 Warm-up time . 11
5.19 Filament material . 11
5.20 Electron emission current . 11
5.21 Filament exchange . 11
5.22 Detector exchange . 11
5.23 Fitting to chamber .12
5.24 Mounting orientation .12
5.25 Dimensions .12
5.26 Internal volume .12
5.27 Mass of sensor head and electronic unit .12
5.28 Input power of electronic unit .12
5.29 Cable .12
5.30 Software .12
5.31 Interface .12
5.32 Storage and transportation condition.12
6 Optional specifications for QMS to be provided by manufacturers .13
6.1 Mass resolution .13
6.2 Fragmentation or cracking pattern .13
6.3 Temperature coefficient of sensitivity .13
6.4 QMS sensor cleaning .13
6.5 Degassing .13
6.6 Degassing power .13
6.7 Photographs .13
6.8 Inspection record .13
6.9 Outgassing rate .13
Bibliography .14
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14291 was prepared by Technical Committee ISO/TC 112, Vacuum technology.
iv © ISO 2012 – All rights reserved

Introduction
Quadrupole mass spectrometers (QMSs) are nowadays used not only for leak detection and residual gas
analysis in vacuum but also as instruments to provide quantitative analysis in processes and control processes
such as physical and chemical vapor deposition, and etch processes.
Total pressure, composition of the gas mixture, QMS settings, environment conditions, etc., have a significant
influence on the measured signal, its uncertainty and interpretation. For this reason, it is not possible to calibrate
QMS for all its possible applications. Instead, it has either to be calibrated for the particular conditions of use
or for a standardized condition.
There is also some need for standardization in order to enable QMS users to compare devices of different
manufacturers and to use the QMS properly.
In continuation of efforts of TC 112 during the 1990s, this International Standard takes a first step towards
establishment of a standardized calibration procedure for QMS by defining the terms and parameters.
INTERNATIONAL STANDARD ISO 14291:2012(E)
Vacuum gauges — Definitions and specifications for
quadrupole mass spectrometers
1 Scope
This International Standard defines terms relevant to quadrupole mass spectrometers (QMSs) and specifies
the parameters required for specification by QMS manufacturers necessary for proper calibration and for
maintaining the quality of partial pressure measurement.
This International Standard applies to QMSs with an ion source of the electron impact ionization type. Such
QMSs are designed for the measurement of atomic mass-to-charge ratios m/z typically <300. QMSs with other
ion sources, such as those of the chemical ionization, photoionization, and field ionization types, as well as the
measurements of m/z above 300, which are mainly used to specify organic materials, lie outside the scope of
this International Standard.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 Definitions of components
2.1.1
quadrupole mass spectrometer
QMS
mass spectrometer in which ions are injected axially into a quadrupole lens consisting of a system of four
electrodes, usually rods, to which radio frequency and d.c. electric fields in a critical ratio are applied, so that
only ions with a certain mass/charge ratio emerge
[2]
[SOURCE: ISO 3529-3:1981, 3.5.2.2]
Note 1 to entry Such a QMS consists of a sensor head and electronic unit.
2.1.2
sensor head
analyser tube
sensor
sensor unit
sensing head
gauge head
equipment consisting of an ion source, quadrupole mass filter, and ion detector in one enclosure
2.1.3
ion source
part of the QMS in which ions of gas molecules and atoms are produced
Note 1 to entry For the production of positive ions, the ion source generally uses an electron impact ionization process.
2.1.3.1
open ion source
ion source with a high conductance to the surrounding vacuum environment, often designed as an open grid structure
Note 1 to entry All of the operational components of this ionization hardware are exposed to the same vacuum region.
2.1.3.2
closed ion source
enclosed ion source
differential pressure ion source
ion source that uses a nearly sealed container to ionize the gas to be analysed with openings only for passing;
sample gas; energetic electrons (for impact ionization); and exciting ions
Note 1 to entry This type of ion source permits ionization at pressures that are higher than the mass filter and detector.
It should be used in a sample pressure reduction system with a high vacuum pump on the mass filter.
2.1.3.3
molecular beam ion source
crossed beam ion source
ion source that
...