EN 14784-1:2005

SLOVENSKI STANDARD
01-november-2005
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Non-destructive testing - Industrial computed radiography with storage phosphor imaging
plates - Part 1: Classification of systems
Zerstörungsfreie Prüfung - Industrielle Computer-Radiographie mit Phosphor-
Speicherfolien - Teil 1: Klassifizierung der Systeme
Essais non destructifs - Radiographie industrielle numérisée avec des plaques-images
au phosphore - Partie 1 : Classification des systemes
Ta slovenski standard je istoveten z: EN 14784-1:2005
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14784-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2005
ICS 19.100
English Version
Non-destructive testing - Industrial computed radiography with
storage phosphor imaging plates - Part 1: Classification of
systems
Essais non destructifs - Radiographie industrielle Zerstörungsfreie Prüfung - Industrielle Computer-
numérisée avec des plaques-images au phosphore - Partie Radiographie mit Phosphor-Speicherfolien - Teil 1:
1 : Classification des systèmes Klassifizierung der Systeme
This European Standard was approved by CEN on 1 July 2005.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14784-1:2005: E
worldwide for CEN national Members.

Contents
Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Personnel qualification .6
5 CR quality indicators.6
6 Procedure for quantitative measurement of image quality parameters .8
7 CR System Classification and Interpretation of Results .15
Annex A (informative) Example for I measurement .18
IPx
Annex B (informative) Example of CR test phantom .22
Annex C (informative) Guidance for application of various tests and test methods .25
Bibliography .27

Foreword
This European Standard (EN 14784-1:2005) has been prepared by Technical Committee CEN/TC 138 “Non-
destructive testing”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2006, and conflicting national standards shall be withdrawn
at the latest by February 2006.
EN 14784 comprises a series of European Standards for industrial computed radiography with storage
phosphor imaging plates which is made up of the following:
EN 14784-1 Non-destructive testing – Industrial computed radiography with storage phosphor imaging plates
– Part 1: Classification of systems
EN 14784-2 Non-destructive testing – Industrial computed radiography with storage phosphor imaging plates
– Part 2: General principles for testing of metallic materials using X-rays and gamma rays
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
1 Scope
This European Standard specifies fundamental parameters of computed radiography systems with the aim of
enabling satisfactory and repeatable results to be obtained economically. The techniques are based both on
fundamental theory and test measurements. This document specifies the performance of computed
radiography (CR) systems and the measurement of the corresponding parameters for the system scanner and
storage phosphor imaging plate (IP). It describes the classification of these systems in combination with
specified metal screens for industrial radiography. It is intended to ensure that the quality of images - as far as
this is influenced by the scanner-IP system - is in conformity with the requirements of Part 2 of this document.
The document relates to the requirements of film radiography defined in EN 584-1 and ISO 11699-1.
This European Standard defines system tests at different levels. More complicated tests are described, which
allow the determination of exact system parameters. They can be used to classify the systems of different
suppliers and make them comparable for users. These tests are specified as manufacturer tests. Some of
them require special tools, which are usually not available in user laboratories. Therefore, simpler user tests
are also described, which are designed for a fast test of the quality of CR systems and long term stability.
There are several factors affecting the quality of a CR image including geometrical un-sharpness, signal/noise
ratio, scatter and contrast sensitivity. There are several additional factors (e.g. scanning parameters), which
affect the accurate reading of images on exposed IPs using an optical scanner.
The quality factors can be determined most accurately by the manufacturer tests as described in this
document. Individual test targets, which are recommended for practical user tests, are described for quality
assurance. These tests can be carried out either separately or by the use of the CR Phantom (Annex B). This
CR Phantom incorporates many of the basic quality assessment methods and those associated with the
correct functioning of a CR system, including the scanner, for reading exposed plates and in correctly erasing
IPs for future use of each plate.
The CR System classes in this document do not refer to any particular manufacturers Imaging Plates. A CR
system class results from the use of a particular imaging plate together with the exposure conditions –
particularly total exposure – the scanner type and the scanning parameters.
2 Normative references
The following referenced documents are indispensable for the application of this European standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 462-5, Non-destructive testing ― Image quality of radiographs ― Part 5: Image quality indicators (duplex
wire type), determination of image unsharpness value.
EN 584-1, Non destructive testing ― Industrial radiographic film ― Part 1: Classification of film systems for
industrial radiography.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply:
3.1
computed radiography system (CR system)
complete system of a storage phosphor imaging plate (IP) and corresponding read-out unit (scanner or
reader) and system software, which converts the information of the IP into a digital image
3.2
computed radiography system class
particular group of storage phosphor imaging plate systems, which is characterised by a SNR (Signal-to-Noise
Ratio) range shown in Table 1 and by a certain basic spatial resolution value (e.g. derived from duplex wire
IQI) in a specified exposure range.
3.3
CEN speed S
CEN
defines the speed of CR systems and is calculated from the reciprocal dose value, measured in Grays, which
is necessary to obtain a specified minimum SNR of a CR system
3.4
signal-to-noise ratio (SNR)
quotient of mean value of the linearised signal intensity and standard deviation of the noise at this signal
intensity. The SNR depends on the radiation dose and the CR system properties.
3.5
modulation transfer function (MTF)
normalised Magnitude of the Fourier-transform (FT) of the differentiated edge spread function (ESF) of the
linearised PSL (photo stimulated luminescence) intensity, measured perpendicular to a sharp edge. MTF
describes the contrast transmission as a function of the object size. MTF characterises the un-sharpness of
the CR system in dependence on the scanning system and IP-type.
3.6
CR phantom
device containing an arrangement of test targets to evaluate the quality of a CR system - as well as monitoring
the quality of the chosen system
3.7
laser beam jitter
lack of smooth movement of the plate laser-scanning device, causing lines in the image consisting of a series
of steps
3.8
scanner slippage
slipping of an IP in a scanner transport system resulting in fluctuation of intensity of horizontal image lines
3.9
aliasing
pre-sampled high spatial frequency signals beyond the Nyquist frequency (given by the pixel distance)
reflected back into the image at lower spatial frequencies
3.10
gain/amplification
opto-electrical gain setting of the scanning system
3.11
linearised signal intensity
numerical signal value of a picture element (pixel) of the digital image, which is proportional to the radiation
dose. The linearised signal intensity is zero, if the radiation dose is zero.
3.12
basic spatial resolution
read-out value of un-sharpness measured with duplex wire IQI according to EN 462-5 divided by 2 as effective
pixel size of CR system
4 Personnel qualification
It is assumed that industrial computed radiography is performed by qualified and capable personnel. In order
to prove this qualification, it is recommended to certify the personnel according to EN 473 or ISO 9712.
5 CR quality indicators
5.1 Description of CR quality indicators for user and manufacturer tests
5.1.1 General
The following is a description of CR quality indicators, which will be identified by reference to this document.
5.1.2 Contrast sensitivity quality indicator
The description of the selected contrast sensitivity targets corresponds to ASTM E1647-98a (see for details
Annex B.4).
5.1.3 Duplex wire quality indicator
The description of the duplex wire quality indicator corresponds to EN 462-5. The IQI shall be positioned at a
5°angle to the direction of the scanned lines (fast scan direction) or the perpendicular direction (slow scan
direction).
5.1.4 Converging line pair quality indicator
The target consist of 5 converging strips of lead (0,03 mm thickness) which can be used for spatial resolution
test by reading the limit of recognisable line pairs. It shall cover a range from 1,5 to 20 line pairs per mm
(lp/mm). Two quality indicators shall be used, one in direction of the scanned lines and the other one in the
perpendicular direction.
5.1.5 Linearity quality indicators
Rulers of high absorbing materials are located on the perimeter of the scanned range. Two quality indicators
shall be used, one in direction of the scanned lines and the other in the perpendicular direction. The scaling
shall be at least in mm.
5.1.6 T-target
This CR quality indicator consists of a thin plate of brass or copper (≤ 0,5 mm thick) with sharp edges. This
plate is manufactured in a T-shape with 5 mm wide segments. The T should have a size of at least
50 mm × 70 mm. It shall be aligned perpendicular and parallel respectively to the direction of the scanned
lines (see Figure B.1).
5.1.7 Scanner slipping quality indicator
It consists of a homogenous strip of aluminium of 0,5 mm thickness. It has a shape of a rectangle (see
Figure B.1) and shall be aligned perpendicular and parallel respectively to the direction of the scanned lines.
5.1.8 Shading quality indicator
Different shading quality indicators may be used.
One type is based on the homogeneous exposure of an imaging plate (IP) with a thin Al-plate (0,5 mm to
1,0 mm) above the IP. The exposure shall be made with low energy radiation (50 keV to 100 keV).
Another type is the shading quality indicator of the CR-test phantom (see Annex B).
5.1.9 Central beam alignment quality indicator (BAM-snail)
The alignment qualit
...