SIST EN 61674:1998
(Main)Medical electrical equipment - Dosimeters with ionization chambers and/or semi-conductor detectors as used in X-ray diagnostic imaging
Medical electrical equipment - Dosimeters with ionization chambers and/or semi-conductor detectors as used in X-ray diagnostic imaging
Specifies the performance and some related constructional requirements of diagnostic dosimeters intended for the measurement of air Kerma, air Kerma length or air Kerma rate, in photon radiation fields used in radiography, including mammography, radioscopy and computed tomography (CT), for X-rays with generating potentials not greater than 150 kV.
Medizinische elektrische Geräte - Dosimeter mit Ionisationskammern und/oder Halbleiterdetektoren für den Einsatz an diagnostischen Röntgeneinrichtungen
Appareils électromédicaux - Dosimètres à chambres d'ionisation et/ou à détecteurs à semi-conducteurs utilisés en imagerie de diagnostic à rayonnement X
Spécifie les prescriptions de performance, et quelques prescriptions de construction associées, des dosimètres de radiodiagnostic destinés aux mesures du Kerma dans l'air, de la longueur de Kerma dans l'air ou du débit de Kerma dans l'air dans des champs de rayonnement de photons utilisés en radiographie, incluant la mammographie, la radioscopie et la tomodensitométrie, pour des rayonnements X dont le potentiel ne dépasse pas 150 kV.
Medical electrical equipment - Dosimeters with ionization chambers and/or semi-conductor detectors as used in x-ray diagnosis imaging (IEC 61674:1997)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61674:1998
01-september-1998
Medical electrical equipment - Dosimeters with ionization chambers and/or semi-
conductor detectors as used in x-ray diagnosis imaging (IEC 61674:1997)
Medical electrical equipment - Dosimeters with ionization chambers and/or semi-
conductor detectors as used in X-ray diagnostic imaging
Medizinische elektrische Geräte - Dosimeter mit Ionisationskammern und/oder
Halbleiterdetektoren für den Einsatz an diagnostischen Röntgeneinrichtungen
Appareils électromédicaux - Dosimètres à chambres d'ionisation et/ou à détecteurs à
semi-conducteurs utilisés en imagerie de diagnostic à rayonnement X
Ta slovenski standard je istoveten z: EN 61674:1997
ICS:
11.040.50 Radiografska oprema Radiographic equipment
17.240 Merjenje sevanja Radiation measurements
SIST EN 61674:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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NORME
CEI
INTERNATIONALE
IEC
61674
INTERNATIONAL
Première édition
STANDARD
First edition
1997-10
Appareils électromédicaux –
Dosimètres à chambres d'ionisation et/ou
à détecteurs à semi-conducteurs utilisés
en imagerie de diagnostic à rayonnement X
Medical electrical equipment –
Dosimeters with ionization chambers and/or
semi-conductor detectors as used in X-ray
diagnostic imaging
IEC 1997 Droits de reproduction réservés Copyright - all rights reserved
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CODE PRIX
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Pour prix, voir catalogue en vigueur
For price, see current catalogue
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61674 © IEC:1997 – 3 –
CONTENTS
Page
FOREWORD . 7
INTRODUCTION . 9
Clause
1 Scope and object . 11
1.1 Scope. 11
1.2 Object . 11
2 Normative references. 11
3 Terminology and definitions . 13
4 General requirements. 27
4.1 Performance requirements. 27
4.2 REFERENCE VALUES and STANDARD TEST VALUES . 27
4.3 General test conditions . 29
4.3.1 STANDARD TEST CONDITIONS. 29
4.3.2 Statistical fluctuations. 29
4.3.3 STABILIZATION TIME. 29
4.3.4 Adjustments during test . 29
4.3.5 Batteries. 29
4.4 Constructional requirements as related to performance . 29
4.4.1 Components. 29
4.4.2 Display. 31
4.4.3 Indication of battery condition . 31
4.4.4 Indication of polarizing voltage failure . 31
4.4.5 Over-ranging. 31
4.4.6 Indication of reset or other inactive condition . 33
4.4.7 MEASURING ASSEMBLIES with multiple DETECTOR ASSEMBLIES . 33
4.4.8 Radioactive STABILITY CHECK DEVICE. 33
4.5 Uncertainty of measurement . 35
5 Limits of PERFORMANCE CHARACTERISTICS . 35
5.1 RELATIVE INTRINSIC ERROR . 35
5.2 Repeatability. 35
5.2.1 Repeatability in the ATTENUATED BEAM. 37
UNATTENUATED BEAM
5.2.2 Repeatability in the . 37
5.3 RESOLUTION of reading. 37
5.4 STABILIZATION TIME . 37
5.5 Effect of pulsed radiation on AIR KERMA and AIR KERMA LENGTH measurements . 37
5.6 Reset on AIR KERMA and AIR KERMA LENGTH ranges . 39
5.7 Effects of LEAKAGE CURRENT. 39
5.7.1 On all AIR KERMA RATE ranges. . 39
5.7.2 On all AIR KERMA and AIR KERMA LENGTH ranges. 39
5.8 Stability. 39
5.8.1 Long term stability . 39
5.8.2 Accumulated dose stability . 39
5.9 Measurements with a radioactive STABILITY CHECK DEVICE. 41
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61674 © IEC:1997 – 5 –
Clause Page
6 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES . 41
6.1 Energy dependence of RESPONSE. 41
6.2 AIR KERMA RATE dependence of AIR KERMA and AIR KERMA LENGTH
measurements. 43
6.2.1 MEASURING ASSEMBLY . 43
6.2.2 IONIZATION CHAMBER – Recombination losses . 43
6.3 Dependence of DETECTOR RESPONSE on angle of incidence of radiation . 45
6.3.1 For non-CT DETECTORS. 45
6.3.2 For CT DETECTORS. 45
6.4 Operating voltage. 45
6.4.1 For mains-operated DOSIMETERS. 45
6.4.2 For battery-operated DOSIMETERS. 45
6.4.3 For mains rechargeable, battery-operated DOSIMETERS . 45
6.5 Air pressure. 47
6.6 Air pressure EQUILIBRATION TIME of the RADIATION DETECTOR . 47
6.7 Temperature and humidity . 47
6.8 Electromagnetic compatibility. 49
6.8.1 Electrostatic discharge. 49
6.8.2 Radiated electromagnetic fields . 49
6.8.3 Conducted disturbances induced by bursts and radio frequencies . 51
6.8.4 Voltage dips, short interruptions and voltage variations . 51
6.9 Field size. 51
6.10 EFFECTIVE LENGTH and spatial uniformity of RESPONSE of CT DOSIMETERS . 53
7 Marking. 53
7.1 DETECTOR ASSEMBLY . 53
7.2 MEASURING ASSEMBLY. 53
7.3 Radioactive STABILITY CHECK DEVICE . 55
8 ACCOMPANYING DOCUMENTS . 55
Tables
EFERENCE STANDARD TEST CONDITIONS
1R and . 57
2 Number of readings required to detect true differences Δ (95 % confidence level)
between two sets of instrument readings. 59
3RELATIVE INTRINSIC ERROR, I, for measurements in the ATTENUATED BEAM. 59
4RELATIVE INTRINSIC ERROR, I, for measurements in the UNATTENUATED BEAM and
in mammography. 61
5 Maximum values for the COEFFICIENT OF VARIATION, v . 61
max
6 Maximum values for the COEFFICIENT OF VARIATION, v . 61
max
7LIMITS OF VARIATION for the effects of INFLUENCE QUANTITIES . 63
Figure 1 – Limits on the RELATIVE INTRINSIC ERROR for AIR KERMA RATE measurements
in the ATTENUATED BEAM. 65
Annexes
A Bibliography . 67
B Index of defined terms . 69
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61674 © IEC:1997 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR
SEMI-CONDUCTOR DETECTORS AS USED
IN X-RAY DIAGNOSTIC IMAGING
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61674 has been prepared by subcommittee 62C: Equipment for
radiotherapy, nuclear medicine and radiation dosimetry, of IEC technical committee 62:
Electrical equipment in medical practice. The text of this standard is based on the following
documents:
FDIS Report on voting
62C/195/FDIS 62C/207/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annexes A and B are for information only.
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61674 © IEC:1997 – 9 –
INTRODUCTION
Diagnostic radiology is the largest contributor to man-made ionizing radiation to which the
public is exposed. The reduction in the exposure received by PATIENTS undergoing medical
radiological examinations or procedures has therefore become a central issue in recent years.
The PATIENT dose will be minimized when the X-ray producing equipment is correctly adjusted
for image quality and radiation output. These adjustments require that the routine
measurement of AIR KERMA, AIR KERMA LENGTH and/or AIR KERMA RATE be made accurately. The
equipment covered by this standard plays an essential part in achieving the required accuracy.
The DOSIMETERS used for adjustment and control measurements must be of satisfactory quality
and must therefore fulfil the special requirements laid down in this standard.
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61674 © IEC:1997 – 11 –
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR
SEMI-CONDUCTOR DETECTORS AS USED
IN X-RAY DIAGNOSTIC IMAGING
1 Scope and object
1.1 Scope
This International Standard specifies the performance and some related constructional
requirements of DIAGNOSTIC DOSIMETERS, as defined in 3.1, intended for the measurement
of AIR KERMA, AIR KERMA LENGTH or AIR KERMA RATE, in photon radiation fields used
in RADIOGRAPHY, including MAMMOGRAPHY, RADIOSCOPY and COMPUTED TOMOGRAPHY (CT), for
X-rays with generating potentials not greater than 150 kV.
This International Standard is applicable to the performance of DOSIMETERS with IONIZATION
CHAMBERS and/or SEMI-CONDUCTOR DETECTORS as used in X-ray diagnostic imaging.
1.2 Object
The object of this standard is:
1) to establish requirements for a satisfactory level of performance for DIAGNOSTIC DOSIMETERS,
and
2) to standardize the methods for the determination of compliance with this level of
performance.
This standard is not concerned with the safety aspects of DOSIMETERS DIAGNOSTIC
. The
DOSIMETERS covered by this standard are not intended for use in physical contact with the
PATIENT and, therefore, the requirements for electrical safety applying to them are contained in
IEC 61010-1.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. Members of
IEC and ISO maintain registers of currently valid International Standards.
IEC 60417: 1973, Graphical symbols for use on equipment – Index, survey and compilation of
the single sheets
IEC 60788: 1984, Medical radiology – Terminology
IEC 61000-4-1: 1992, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 1: Overview of immunity tests – Basic EMC publication
IEC 61000-4-2: 1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test – Basic EMC publication
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61674 © IEC:1997 – 13 –
IEC 61000-4-3: 1995, Electromagnetic compatibility (EMC) – Part 4:Testing and measurement
techniques – Section 3: Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4: 1995, Electromagnetic compatibility (EMC) – Part 4:Testing and measurement
techniques – Section 4: Electrical fast transient/burst immunity test – Basic EMC publication
IEC 61000-4-5: 1995, Electromagnetic compatibility (EMC) – Part 4:Testing and measurement
techniques – Section 5: Surge immunity tests
IEC 61000-4-6: 1996, Electromagnetic compatibility (EMC) – Part 4:Testing and measurement
techniques – Section 6: Immunity to conducted disturbances induced by radio frequency fields
IEC 61000-4-11: 1994, Electromagnetic compatibility (EMC) – Part 4:Testing and measurement
techniques – Section 11: Voltage dips, short interruptions and voltage variations immunity
test – Basic EMC publication
IEC 61187: 1993, Electrical and electronic measuring equipment – Documentation
IEC 61267: 1994, Medical diagnostic X-ray equipment – Radiation conditions for use in the
determination of characteristics
3 Terminology and definitions
In this standard the auxiliary verb:
– "shall" implies that compliance with a requirement is mandatory for compliance with the
standard;
– "may" implies that compliance with a requirement is permitted to be accomplished in a
particular manner for compliance with the standard.
The definitions given in this international standard are generally in agreement with those in:
– IEC 60788:1984, Medical radiology – Terminology
– ISO:1993, International vocabulary of basic and general terms in metrology, 2nd. ed.;
but some definitions have been given a more restricted meaning. Such special definitions shall
be regarded as applying only to this standard.
Terms not defined in this clause have the meanings defined in the above publications or are
assumed to be terms of general scientific usage. An alphabetical list of the defined terms is
given in annex B.
For the purpose of this international standard the following definitions apply:
3.1
(DIAGNOSTIC) DOSIMETER
Equipment which uses IONIZATION CHAMBERS and/or SEMI-CONDUCTOR DETECTORS for the
measurement of AIR KERMA, AIR KERMA LENGTH and/or AIR KERMA RATE in the beam of an X-ray
machine used for diagnostic medical radiological examinations.
A DIAGNOSTIC DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES which may or may not be an integral part of the
MEASURING ASSEMBLY;
–a MEASURING ASSEMBLY;
– one or more STABILITY CHECK DEVICES (optional).
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61674 © IEC:1997 – 15 –
3.1.1
DETECTOR ASSEMBLY
RADIATION DETECTOR and all other parts to which the RADIATION DETECTOR is permanently
attached, except the MEASURING ASSEMBLY.
NOTE – The DETECTOR ASSEMBLY normally includes:
– the RADIATION DETECTOR and the stem (or body) on which the RADIATION DETECTOR is permanently mounted
(or embedded);
– the electrical fitting and any permanently attached cable or pre-amplifier.
3.1.1.1.
RADIATION DETECTOR
Element which transduces AIR KERMA, AIR KERMA LENGTH or AIR KERMA RATE into a measurable
electrical signal. It may be either an IONIZATION CHAMBER or a SEMI-CONDUCTOR DETECTOR:
1) IONIZATION CHAMBER: Ionization detector consisting of a chamber filled with air, in which an
electric field insufficient to induce gas multiplication is provided for the collection, at the
electrodes, of charges associated with the ions and electrons produced in the sensitive
volume of the detector by ionizing radiation. The chamber is constructed in such a way as to
allow the air inside the measuring volume to communicate freely with the atmosphere so
that corrections to the RESPONSE for changes in air density need to be made.
2) VENTED CHAMBER: An IONIZATION CHAMBER constructed in such a way as to allow the air
inside the measuring volume to communicate freely with the atmosphere so that corrections
to the RESPONSE for changes in air density need to be made.
NOTE - Sealed chambers are not suitable, because the necessary wall thickness of a sealed chamber may cause
an unacceptable energy dependence of the RESPONSE and because the long term stability of sealed chambers is not
guaranteed.
3) SEMI-CONDUCTOR DETECTOR: Either a) and/or b):
a) semi-conductor device operating in the shorted junction mode that utilizes the production
and motion of excess free charge carriers in the semi-conductor for the detection and
measurement of incident ionizing radiation;
b) scintillator material optically coupled to a semi-conductor photodiode operating in the
shorted junction mode, in which assembly incident ionizing radiation is first converted to
light and then to an electrical signal.
3.1.2
MEASURING ASSEMBLY
Device to convert the output from the DETECTOR ASSEMBLY into a form suitable for the display of
the value(s) of AIR KERMA, AIR KERMA LENGTH or AIR KERMA RATE.
3.1.3
STABILITY CHECK DEVICE
Device, either separate or integral part of the DIAGNOSTIC DOSIMETER, which enables the
stability of the RESPONSE of the RADIATION DETECTOR and/or MEASURING ASSEMBLY to be
checked.
NOTE - The STABILITY CHECK DEVICE may be a purely electrical device, or a radiation source, or it may include both.
3.1.4
CT DOSIMETER
DIAGNOSTIC DOSIMETER which uses long narrow IONIZATION CHAMBERS and/or SEMI-CONDUCTOR
DETECTORS for the measurement of AIR KERMA integrated along the length of the DETECTOR
when the DETECTOR is exposed to a cross-sectional X-ray scan of a computed tomographic
machine.
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61674 © IEC:1997 – 17 –
A CT DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES;
–a MEASURING ASSEMBLY.
3.1.5
CT DETECTOR
RADIATION DETECTOR which is used for CT dosimetry.
3.2
INDICATED VALUE
Value of a quantity derived from the scale reading of an instrument together with any scale
factors indicated on the control panel of the instrument.
3.3
TRUE VALUE
Value of the physical quantity to be measured by an instrument.
3.4
CONVENTIONAL TRUE VALUE
The value used instead of the TRUE VALUE when calibrating or determining the performance of
an instrument, since in practice the TRUE VALUE is unknown and unknowable.
NOTE - The CONVENTIONAL TRUE VALUE will usually be the value determined by the STANDARD with which the
instrument under test is compared.
3.4.1
STANDARD
Instrument which defines, represents physically, maintains or reproduces the unit of
measurement of a quantity (or a multiple or sub-multiple of that unit) in order to transfer it to
other instruments by comparison.
3.5
MEASURED VALUE
Best estimate of the TRUE VALUE of a quantity, derived from the INDICATED VALUE of an
instrument together with the application of all relevant CORRECTION FACTORS.
3.5.1
ERROR OF MEASUREMENT
Difference between the MEASURED VALUE of a quantity and the TRUE VALUE of that quantity.
3.5.2
OVERALL UNCERTAINTY
Uncertainty associated with the MEASURED VALUE, i.e. representing the bounds within which the
ERROR OF MEASUREMENT is estimated to lie (see also 4.5).
3.5.3
EXPANDED UNCERTAINTY
Quantity defining the interval about the result of a measurement within which the values that
could reasonably be attributed to the measurand may be expected to lie with a higher degree of
confidence.
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61674 © IEC:1997 – 19 –
3.6
CORRECTION FACTOR
Dimensionless multiplier which corrects the INDICATED VALUE of an instrument from its value
when operated under particular conditions to its value when operated under stated REFERENCE
CONDITIONS.
3.7
INFLUENCE QUANTITY
Any external quantity that may affect the performance of an instrument (e.g. ambient
temperature, radiation quality, etc.).
3.8
INSTRUMENT PARAMETER
Any internal property of an instrument that may affect the performance of this instrument.
3.9
REFERENCE VALUE
Particular value of an INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) chosen for the purpose
of reference, i.e. the value of an INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) at which the
CORRECTION FACTOR for dependence on that INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) is
unity.
3.9.1
REFERENCE CONDITIONS
Conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
REFERENCE VALUES.
3.10
STANDARD TEST VALUES
Value(s), or range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER which are
permitted when carrying out calibrations or tests on another INFLUENCE QUANTITY or INSTRUMENT
PARAMETER.
3.10.1
STANDARD TEST CONDITIONS
Conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
STANDARD TEST VALUES.
3.11
INTRINSIC ERROR
Deviation of the MEASURED VALUE (i.e. the INDICATED VALUE, corrected to REFERENCE
CONDITIONS) from the CONVENTIONAL TRUE VALUE under STANDARD TEST CONDITIONS.
3.11.1
RELATIVE INTRINSIC ERROR
Ratio of the INTRINSIC ERROR to the CONVENTIONAL TRUE VALUE.
3.12
PERFORMANCE CHARACTERISTIC
One of the quantities used to define the performance of an instrument (e.g. RESPONSE,
LEAKAGE CURRENT).
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61674 © IEC:1997 – 21 –
3.12.1
RESPONSE
Quotient of the INDICATED VALUE by the CONVENTIONAL TRUE VALUE.
3.12.2
RESOLUTION OF THE DISPLAY
Smallest change of scale reading to which a numerical value can be assigned without further
interpolation:
– for an analogue display, the RESOLUTION is the smallest fraction of a scale interval that can
be determined by an observer under specified conditions;
– for a digital display, the RESOLUTION is the smallest significant increment of the reading.
3.12.3
EQUILIBRATION TIME
Time taken for a scale reading to reach and remain within a specified deviation from its final
steady value, after a sudden change in an INFLUENCE QUANTITY has been applied to the
instrument.
3.12.4
RESPONSE TIME
The time taken for a scale reading to reach and remain within a specified deviation from its
final steady value, after a sudden change in the quantity being measured.
3.12.5
STABILIZATION TIME
Time taken for a stated PERFORMANCE CHARACTERISTIC to reach and remain within a specified
deviation from its final steady value, after the DOSIMETER has been switched on (and, if the
RADIATION DETECTOR is an IONIZATION CHAMBER, after the polarizing voltage has been applied).
3.12.6
LEAKAGE CURRENT
Any current in the signal path arising in the DETECTOR and/or MEASURING ASSEMBLY which is not
produced by ionization in the RADIATION DETECTOR.
3.13
VARIATION
Relative difference, Δy/y, between the values of a PERFORMANCE CHARACTERISTIC, y, when one
INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) successively assumes two specified values,
the other INFLUENCE QUANTITIES (and INSTRUMENT PARAMETERS) being kept constant at the
STANDARD TEST VALUES (unless other values are specified).
3.14
LIMITS OF VARIATION
Maximum VARIATION of a PERFORMANCE CHARACTERISTIC, y, permitted by this standard. If LIMITS
OF VARIATION are stated as ±L %, the VARIATION, Δy/y, expressed as a percentage, shall remain
in the range from –L % to +L %.
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61674 © IEC:1997 – 23 –
3.15
EFFECTIVE RANGE (of INDICATED VALUES)
Range of INDICATED VALUES for which an instrument complies with a stated performance, the
maximum (minimum) EFFECTIVE INDICATED VALUE is the highest (lowest) in this range.
The concept of EFFECTIVE RANGE may also be applied to scale readings and to related
quantities that are not directly indicated by the instrument, for example the input signal.
NOTE 1 – The EFFECTIVE RANGE of INDICATED VALUES is referred to as EFFECTIVE RANGE in this standard.
NOTE 2 – For CT DOSIMETERS the EFFECTIVE RANGE of AIR KERMA LENGTH need not be stated as the largest range of
AIR KERMA LENGTH values that it is possible to measure with the equipment. Rather, it may be restricted to the range
which is of practical interest to the USER, e.g. 1μGy·m to 2mGy·m.
3.16
RATED RANGE (of USE)
Range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER within which the
instrument will operate within the LIMITS OF VARIATION. Its limits are the maximum and minimum
RATED values.
NOTE - The RATED RANGE of USE is referred to as RATED RANGE in this standard.
3.16.1
MINIMUM RATED RANGE
The least range of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER within which the
in
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