ISO/DIS 22029

DRAFT INTERNATIONAL STANDARD
ISO/DIS 22029
ISO/TC 202 Secretariat: SAC
Voting begins on: Voting terminates on:
2020-01-13 2020-04-06
Microbeam analysis — EMSA/MAS standard file format for
spectral-data exchange

Analyse par microfaisceaux — Format de fichier standard EMSA/MAS pour échange de données

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Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 General considerations .................................................................................................................................................................................. 1

3 Format Description ............................................................................................................................................................................................ 2

3.1 General ........................................................................................................................................................................................................... 2

3.2 Required Keywords ............................................................................................................................................................................. 3

3.3 Spectral Data ............................................................................................................................................................................................. 4

3.4 Optional Keywords .............................................................................................................................................................................. 5

3.5 Ending A File ............................................................................................................................................................................................. 9

4 Example Of A Data File In The EMSA/MAS Spectral Format .................................................................................... 9

Bibliography .............................................................................................................................................................................................................................11

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

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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

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.

This third edition cancels and replaces the second edition (ISO 22029:2012), which has been technically

The original EMSA/MAS Standard File Format for Spectral Data Exchange was published in October

1991. Since then, advances in both microbeam analysis techniques and in PC technology have meant

that this original standard is not fully able to meet modern requirements. The members of ISO/TC 202

(the International Organization for Standardization Technical Committee for Microbeam Analysis)

propose this updated version. Every effort has been made to only make those changes that improve or

update the applicability of the standard, while minimizing incompatibility with the original version.

The remit of TC 202 does not include surface analysis techniques, which are addressed by TC 201, and

so references to these techniques have been removed from the original standard where necessary. The

original document also included examples of coding and telecommunications protocols. Since these are

now largely outdated, and not integral to the formatting of the data, these have also been removed.

It is noted that one of the originating societies (EMSA) has modified its name since the original document

was published. The society is now officially known as the “Microscopy Society of America”, or MSA, the

term “Electron” having been dropped to more fully indicate the work and interest of the membership of

Nine new optional user defined keywords have been added to this edition to improve the ability of

the standard to more fully describe the instrument and analysis conditions, while still maintaining

backward compatibility with data readers and writers conforming with earlier versions of the standard.

This International Standard presents a simple format for the exchange of digital spectral data that has

been designated as an EMSA/MAS standard. This format is readable by both humans and computers

and is suitable for transmission through various electronic networks, the phone system (with modems)

or on physical computer storage devices (such as removable media). The format is not tied to any one

computer, programming language or computer operating system. The adoption of a standard format

would enable different laboratories to freely exchange spectral data, and would help to standardize

data analysis software. If equipment manufacturers were to support a common format, the microscopy

and microanalysis community would avoid duplicated effort in writing data analysis software.

The virtues of a single standard data format have been admirably related by various authors , , , .

It would often be convenient, after visiting another laboratory to use a different type of microanalytical

spectrometer, to be able to return to one’s own laboratory to analyse the data, or for a laboratory to be

able to send a spectrum to another group at another location for analysis on their computer. A common

format would also enable test spectra to be transported between data acquisition systems, in order to

compare different data analysis routines, and would give users greater choice of analysis procedure,

Obviously, an ideal solution would be for the manufacturers to represent data in a standard format,

but they are unlikely to agree on this without some direction from their customers (the microanalysis

community). Therefore it is highly desirable for EMSA and MAS to proceed with the adoption of a

standard format. Such a format does not preclude any research group or manufacturer from having

their own, possibly proprietary, format. Spectral data can be stored internally in any format, as long as

there is an option to convert it to the external standard (and vice versa) for the purposes of exchange.

a) It should be capable of representing the data exactly (without altering the scientific content).

c) It must NOT be tied to any particular computer, programming language or operating system. It

should work on a large number of computers of all sizes, although we cannot guarantee that it will

e) It should be compatible with existing electronic communication networks and with the phone

system (using modems). Future networks will likely retain compatibility with these.

f) The format should support spectra of interest to the microanalysis community (such as XEDS,

EELS, AES) and should be flexible enough to accommodate future data sets not yet specified.

g) Each file should contain enough information to uniquely identify the type and origin of the spectral

h) Where possible, the format should be compatible with various commercial data plotting or analysis

i) The proposed format need not be the most efficient storage mechanism. Its primary goals, stated

above, will generally prevent storage efficiency. If anything, this format will err on the side of

The format originally employed by the Electron Microscopy and Microanalysis Public Domain Library

(EMMPDL) at Argonne has the virtue of simplicity, but is too rigid for general use. A recent revision

corrected some inadequacies, but a more serious re-examination is in order. The format proposed by a

previous EMSA task force addresses many of the problems, but is thought by some microscopists to

be too complicated for everyday use. The VAMAS format, whose description runs to 60 pages, is also

too complex for our perceived purpose. A format, named JCAMP-DX, used by the infrared-spectroscopy

community is specific and detailed, but is somewhat off target for the spectroscopies of interest to

The format proposed here follows JCAMP-DX in many ways but is less complicated and has features

tailored to X-ray, energy-loss and Auger spectroscopies. We circulated a preliminary version of this

proposal to several manufacturers of XEDS systems and have received back comments and suggestions,

The companion problem of a standard format for digital-image storage is similar to that of spectral

data but is sufficiently different to warrant its own standard. Whereas most spectra are sufficiently

compact that they can be stored in a human-readable form, image data are usually so extensive as to

require storage of “raw” binary numbers. There exist formats for image storage that are in widespread

use. One of these (probably TIFF) should be endorsed by EMSA and MAS, allowing the microanalysis

community to take advantage of the large amount of commercial and public-domain software already

The general structure of the data file format can be summarized as a simple sequential text file. It

begins with a series of header lines which serve to define the characteristics of the spectrum. These

header lines are identified by unique keyword fields which occupy the first 15 positions of each line,

followed by a data field. These are described in detail below. After the header lines, a keyword indicates

the start of data, and the data then follow on successive lines in a manner which is defined explicitly

within the header. Finally, after all the data are presented, an end-of-data keyword indicates that the

Successive lines beginning with EMSA/MAS-defined keywords, some of which are required and some

In general, each line of the file either contains a keyword and its associated value or spectral data. All

header lines are readily identified as they each begin with “#” in the first character field or column. This

symbol demarks the start of a 13 character keyword field, providing descriptive information about the

data followed by an associated value. EMSA/MAS-defined keywords (whose definition may be changed

only by EMSA/MAS) begin with a single # and occupy the first 13 columns (characters) of each header

line. The keyword itself consists of at most 12 characters, which directly follow the #. Shorter

keywords may be employed, and any remaining spaces following the defined keyword may be filled

with descriptive text such as unit designation for ease of legibility when the file is printed (see example

in Table 1). If a position in the keyword field is not used, it must be filled with a space character. The

keywords are not case-sensitive, so that #Xunits is interpreted as being the same as #XUNITS.

The 14th and 15th character positions (columns) in each header line are occupied by keyword/value

field separators, which consist of a colon followed by a space. The value associated with each keyword

starts in column 16 and may be either textual or numeric as defined by the keyword. Each line of the

file may contain no more than 79 characters (for compatibility with the largest number of computers

and computer networks, and for general legibility on standard-width CRT screens). Since the keyword

and its separator occupies the first 15 positions, this means that all remaining information following

the keyword is limited to a maximum of 64 (79 − 15) character positions. The end-of-line indicator is a

The only characters allowed in the file, except where explicitly stated, are the space (ASCII character

32), carriage return (ASCII character 13) and linefeed (ASCII character 10) characters, plus the printable

Horizontal TAB characters are NOT permitted in this file format as a substitute for spaces or commas.

Examples of keywords, separators and data can be found in Table 1, and are further