AS 1929—1981
Australian Standard
NON-DESTRUCTIVE TESTING
GLOSSARY OF TERMS
The following scientific, industrial and governmental organizations and departments
were officially represented on the committee entrusted with the preparation of this
standard:
Australian Atomic Energy Commission
Australian Gas Association
Australian Institute for Non-destructive Testing
Australian Welding Institute
Bureau of Steel Manufacturers of Australia
Confederation of Australian Industry
Department of Defence
Department of Industrial Relations, N.S.W.
Department of Labour and Industry, Victoria
Department of Productivity
Electricity Supply Association of Australia
Institute of Australian Foundrymen (N.S.W. Division)
National Association of Testing Authorities
Railways of Australia Committee
Society of Automotive Engineers—Australasia
This standard, prepared by Committee MT/7, Non-destructive Testing of Metals and
Materials, was approved on behalf of the Council of the Standards Association of
Australia on 19 February 1981, and was published on 1 June 1981.
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to periodic review and are kept up to date by the issue of amendments or new editi ons as necessary. It is
important therefore that Standards users ensure that they are in possession of the latest editi on, and any
amendments thereto.
Full detail s of all Australi an Standards and related publications will be found in the Standards Australi a
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AS 1929—1981
Australian Standard
NON-DESTRUCTIVE TESTING
GLOSSARY OF TERMS
First publi shed (as AS B259 Pts 1-5) . . . . . . . . . 1968
AS 1929 fi rst published . . . . . . . . . . . . . . . . . . 1977
Second editi on . . . . . . . . . . . . . . . . . . . . . . . . 1981
PUBLISHED BY STANDARDS AUSTRALIA
(STANDARDS ASSOCIATION OF AUSTRALIA)
1 THE CRESCENT, HOMEBUSH, NSW 2140
ISBN 0 7262 2205 4
AS 1929—1981
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PREFACE
This edition of this standard was prepared by the Association’s Committee on Nondestructive Testing to replace the 1977 edition which was a revision of AS B259,
Parts 1 to 5—1968.
Some terms have been deleted because their meaning is not restricted to nondestructive testing. Known errors have been corrected and additional terms added. Of
significance are those related to radioactivity; in particular the rad, rem and roentgen
have been replaced by the SI units gray (Gy), sievert (Sv) and coulombs per kilogram
(C/kg) respectively. The numbers allocated to the terms for reference from the Index
have been deleted and the Index now gives only the relevant Section number, the terms
within the Sections being in alphabetical order.
AS B259, which was BS 3683, Parts 1 to 5, endorsed as the Australian standard, was
issued in separate parts. The committee decided that Australian industry would be best
served by the issue of one glossary which covered all the fields of non-destructive
testing. This standard accordingly reflects that decision.
During preparation of the standard, BS 3683, Parts 1 to 5, and the following
publications were considered:
ISO/R 947—
Explanations on the Significance of the Principal Radiographic
Addendum 1
Terms Used in ISO Recommendations
BS 3455
Glossary of Terms Used in Nuclear Science and Technology
ASTM E 268—1968 Terms Relating to Electromagnetic Testing.
The committee also considered a publication issued by the Aerospace Industries
Association (USA) ‘Glossary of Terms Frequently Used in Non-destructive Testing’.
Acknowledgement is made of the assistance obtained from these sources.
Terms which specifically relate to a particular field of testing have been placed in the
appropriate section, cross referencing being used where terms are related. General
physical terms which have widespread use and are not confined to non-destructive
testing have not been included.
CONTENTS
Page
GLOSSARY
Section 1. General Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section 2. Terms Used in Acoustic Testing . . . . . . . . . . . . . . . . . . .
Section 3. Terms Used in Electromagnetic Testing . . . . . . . . . . . . . .
Section 4. Terms Used in Magnetic Particle Testing . . . . . . . . . . . . .
Section 5. Terms Used in Penetrant Testing . . . . . . . . . . . . . . . . . . .
Section 6. Terms Used in Radiation Testing . . . . . . . . . . . . . . . . . . .
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3
AS 1929—1981
STANDARDS ASSOCIATION OF AUSTRALIA
Australian Standard
for
NON-DESTRUCTIVE TESTING—GLOSSARY OF TERMS
SECTION 1. GENERAL TERMS
Term
Defi niti on
acoustic testing
The method of non-destructive testing which uses acoustic energy usually within the
frequency range 1 MHz to 5 MHz.
defect
A discontinuity whose size, shape, orientation, location or properties make it detrimental
to the useful service of the product in which it occurs or which exceeds the accept/reject
criteria for the given design.
discontinuity
Any imperfection or interruption in the normal physical structure or configuration of a
product, such as cracks, laps, seams, inclusions, porosity, lamination or change in grain
structure.
eddy correct testing
The method in which eddy current flow is induced and monitored in the product under
test. Changes in current flow are subsequently analysed.
electromagnetic testing
The method of non-destructive testing which uses electromagnetic energy having
frequencies less than visible light. It covers eddy current, magnetic field, leakage field
pick-up and direct current conduction tests.
indication
A response or evidence of a response in non destructive testing that requires
interpretation to determine its significance.
magnetic particle testing
The method of non-destructive testing which involves the generation of a magnetic flux
within magnetic materials, used to detect surface or near surface discontinuities. Testing
also involves the application of suitable magnetic particles to the surface of the material
to give an indication of a discontinuity.
non-destructive testing
Testing of materials to detect internal, surface and concealed defects or discontinuities
using methods which do not damage or destroy the material under test.
penetrant testing
The method of non-destructive testing which involves the application of a penetrant to
materials to detect and locate discontinuities such as laps, folds, cracks, porosity and
fissures which are open to the surface. The method also involves the removal of excess
penetrant, and, if necessary, the application of a developer to produce a visible indication
of a discontinuity.
radiation testing
The method of non-destructive testing which uses X-rays or gamma rays in order to
produce a graphic record on sensitized film which indicates comparative soundness of the
material under test.
NOTE: A discontinuity may or may not aff ect the usefulness of the product.
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SECTION 2. TERMS USED IN ACOUSTIC TESTING
Term
Defi niti on
A-scan presentation
A form of display in rectangular coordinates, in which pulse amplitude is represented as
a displacement along one axis, and time is represented as a displacement along the other
axes (see Fig 2.1(a)).
NOTE: The A-scan display, as shown on the conventional cathode-ray tube, may be in one of the
forms il lustrated in Fig 2.1 (b).
Fig. 2.1 (a). SIMPLIFIED A-SCA N PR ES EN TATION
Unrectif ied
A-scan display
Rectif ied and
unfi lt ered
A-scan display
Rectif ied and
fi lt ered
A-scan display
Fig. 2.1 (b). FORMS OF A-SC AN DISP LAY
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Term
Defi niti on
acoustic absorption
The component of ultrasonic wave attenuation resulting from ultrasonic energy being
converted into heat energy.
The means of transferring ultrasonic energy between two media, generally between a
probe and material under test. In the case of two solids, a couplant is generally placed
between them to assist in the transfer of ultrasonic energy.
Any interface between two media of different acoustic impedance which will cause some
or all of the acoustic energy incident upon it to be reflected.
The number of oscillations per second experienced by a particle or point in a medium
caused by the passage of an acoustic wave through it.
The product of density and sound velocity. The property which determines acoustic
transmission across a boundary between two media.
The coupling of two media to provide optimum transfer of ultrasonic energy between
them.
The effect produced in a body by its geometry or by a discontinuity in it, whereby
ultrasonic energy, when travelling in a particular direction is prevented from reaching a
certain region within the body.
acoustic coupling
acoustic discontinuity
acoustic frequency
acoustic impedance
acoustic impedance matching
acoustic shadow
angle of beam spread
angle of divergence
The solid angle which contains the main lobe of an ultrasonic beam in the far zone (see
Fig 2.2).
N = Near zone
F = Far zone
θ = Angle of beam spread
D = Diameter of crystal
NOTE: Approximate beam spread can be
calculated fr om the foll owing formula:
where
D = diameter of crystal
λ =
K =
wavelength
constant for amplit ude reduction to
maximum at beam axis
For 50 percent reducti on (6 dB) =
For 90 percent reducti on (20 dB)
At extr eme edge of beam
K = 0.56
K = 1.08
K = 1.22
Fig. 2.2. SIMPLIFIED DIAG RA M OF BEA M SPR EA D
angle of incidence
angle of reflection
angle of refraction
The angle that the axis of an acoustic beam makes with the normal to a surface at the
point of incidence (see Fig. 2.3).
The angle that the axis of a reflected acoustic beam makes with the normal to a reflecting
surface at the point of incidence (see Fig. 2.3).
The angle between the axis of a refracted beam and the line normal to the boundary
between two media of different acoustic velocity (see Fig. 2.3).
αi = angle of incidence
αs = angle of reflection
αr = angle of refraction
The angle of refl ecti on (αs) will be equal to the angle of incidence
(αi), provided that no mode transformation has occurr ed.
In the case of the refr acted beam =
Fig. 2.3. BE HA VIOUR OF AN ULTRAS ONIC BEA M AT INTERFAC E
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Term
Defi niti on
angle probe
A contact probe by means of which ultrasonic waves can be introduced into a test object
so that the beam axis is at an angle, other than 0 degrees or 90 degrees, to the normal to
the contact plane.
A curve showing the relationship between the different areas of reflectors located at a
constant distance from a probe and the respective amplitudes of their indications.
The loss of acoustic energy within a medium due to scattering and absorption.
The acoustic energy loss between two points, in a given medium, separated by a given
distance.
area amplitude curve
attenuation
attenuation coefficient
attenuation factor
NOTE: Usually expressed in decibels per mill imetre (dB/mm).
attenuator
AV G (diagram)
automatic gain control (AG C)
back echo
back-wall echo
B-scan presentation
A device which may be incorporated in an ultrasonic test system which enables the
electrical signals received from an acoustic transducer to be decreased by a known value,
usually in decibels.
See DG S diagram
The means of automatically controlling the gain of the receiver amplifier in order to
maintain a constant test sensitivity over a limited range.
An ultrasonic pulse reflected from the boundary of a body normal to the beam axis.
A form of display, in rectangular coordinates, in which the travel time of an ultrasonic
pulse is represented as a displacement along one axis, and probe movement (generally
rectilinear) is represented as a displacement along the other axis. In the display, reflected
pulses are shown as bright marks on a dark background, or vice versa (see Fig. 2.4).
Fig. 2.4. SIMPLIFIED B-SC AN PR ES EN TATION
beam axis
beam index
beam path length
beam profile
beam spread
boundary echo
C-scan presentation
calibration block
compression wave
compression wave probe
corner effect
couplant
critical angle
cross-talk
crystal (ultrasonic)
The locus of points of maximum intensity in the far zone in a beam of acoustic energy,
and its projection back into the near zone (see Fig. 2.2).
The point on the surface of a body on which the beam axis is incident (of probe index).
Any distance measured along the beam axis.
The plot of the sound pressure distribution within the beam.
The solid angle which contains the main lobe of an ultrasonic beam in the far zone (see
also angle of beam spread).
An ultrasonic pulse reflected from the boundary of a body by the shortest beam path (not
necessarily by the shortest path).
The line-by-line presentation of data obtained so that discontinuities are shown in terms
of probe position at the moment of detection. The presentation is usually recorded on
paper or film, i.e. a two-dimensional presentation (see Fig. 2.5).
A piece of material of specified composition, heat treatment, geometric form and surface
finish, by means of which the performance characteristics of ultrasonic equipment can be
assessed and calibrated. (See also reference block.)
A form of wave motion in any medium in which the particle displacement is parallel to
the direction of propagation.
A probe for generating and/or receiving compression waves.
The reflection of acoustic energy after impinging successively on two or three orthogonal
surfaces.
A medium interposed between two solids to assist the transfer of acoustic energy.
The incident angle of an ultrasonic signal at which a specified reflected or refracted mode
ceases to exist (see Fig. 2.6).
Acoustic interference produced in the receiving transducer of a double transducer system
by energy generated by the transmitting transducer.
Portion of a single crystal or polycrystalline sintered ceramic having piezo-electric
properties, used for the generation and/or detection of ultrasonic energy.
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Term
Defi niti on
crystal backing
crystal mosaic
Material attached to the rear surface of a crystal to increase damping.
An assembly of ultrasonic crystals mounted in such a way that it tends to behave as
though it were a single crystal.
Fig. 2.5 SIMPLIFIED C-SCA N PRE SE NTATION
NOTE: In the above examples for a Perspex/steel interface at angles of incidence less than the fi rst
crit ical angle, two refracted modes coexist within the steel. At angles of incidence between the fi rst
crit ical angle and the second cri ti cal angle, only the refracted shear wave mode exists. At angles of
incidence greater than the second cri ti cal angle neit her refr acted mode exists.
Fig. 2.6 CRITICA L AN GLES FOR PE RS PE X/STEE L INTER FACE
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Term
Defi niti on
damping (probe construction)
dead zone
Limitation of the duration of oscillation of a transducer by mechanical means.
The unusable portion of a display trace adjacent to the initial pulse indication due to the
characteristics of the ultrasonic flaw detector an probe (see Fig. 2.7) (see also near zone,
far zone).
For theoretical calculati on of near zone length—
where
N = near zone length, in mil li metr es
D = diameter of crystal, in mill imetres
λ = wavelength, in mill imetres
Fig. 2.7. DISTANCE/AMPLITUDE CURVE SHOWING LOCATION OF ZONES IN
AN ULTRASONIC BEAM
decay method
decibel (dB)
The use of ultrasonic energy to assess the quality of a material or a bond by studying the
amplitudes of successive multiple echoes.
A comparative measure of two signal amplitudes, obtained by multiplying by ten the
common logarithm of the ratio of the power of the two signals:
or 20 log10
dB = 10 log10
where V1 and V2 are the signal amplitudes.
The following table relates to percentage of amplitude decibels:
dB
Positi ve
percent
Negati ve
percent
0
0.5
1.0
100
106
112
100
94.5
89
1.5
2.0
2.5
119
126
133
84
79
75
3.0
3.5
4.0
141
150
158
71
67
63
4.5
5.0
6.0
168
178
200
60
56
50
7.0
8.0
9.0
204
251
282
45
40
35
10.0
12.0
14.0
316
400
500
32
25
20
16.0
18.0
20.0
630
800
1000
16
12.6
10
30.0
40.0
50.0
3200
10 × 10 3
32 × 10 3
—
—
—
60.0
70.0
80.0
100 × 103
320 × 103
1 × 106
—
—
—
90.0
100.0
3.2 × 106
1 × 107
—
—
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Term
Defi niti on
defect
A discontinuity whose size, shape, orientation, location or properties make it detrimental
to the useful service of the product in which it occurs or which exceeds the accept/reject
criteria for the given design.
The time interval between the transmission of a pulse and the initiation of the time base
sweep.
The graphical presentation of the relative amplitudes of ultrasonic echoes received from
from ideal reflectors of different sizes and at different distances.
A system of discontinuity size estimation based on the use of DG S diagrams.
Reflection of ultrasonic energy from a rough surface in a manner such that the reflected
energy is detectable over a range of angles on either side of the theoretical angle of
(specular) reflection, i.e. reflection in a non-specular manner.
The relationship between the angle of incidence of the ultrasonic energy and the
amplitude of the resulting received echo.
Any imperfection or interruption in the normal physical structure or configuration of a
product, such as cracks, laps, seams, inclusions, porosity or laminations. A discontinuity
may or may not affect the usefulness of the product.
A curve showing the amplitude of ultrasonic indications from reflectors of equal size at
different distances in an ultrasonic transmitting medium.
That frequency at which the overall response of an ultrasonic pulse-echo flaw detection
system is a maximum.
delay
DG S diagram
distance-gain-size-diagram
DG S system
diffuse reflection
directional sensitivity
discontinuity
distance amplitude curve
dominant frequency
NOTE: The ‘system’ includes the probe as a tr ansmit ti ng element, the pulse propagati on path, the
probe as a receiving element, and electr onic instr umentati on associated with receiving, ampli fying
and displaying a received signal.
double crystal probe
double probe method
dynamic range
A probe incorporating two acoustically separated crystals in a single housing, one of
which acts as a transmitter of acoustic energy and the other as a receiver.
The use of one probe as a transmitter of acoustic energy, and a second probe as the
receiver.
The difference in amplitude, measured in dB, between the largest and smallest signals of
measurable height, which are capable of being simultaneously displayed in A-scan
presentation.
NOTE: In A-scan presentati on a signal of height 2 mm is often taken as the smallest measurable
signal. On this basis, if the largest measurable signal is of height 60 mm, and li nearit y of
amplif ication is maintained over the full height of the display, the dynamic range would be
20 log10 30 = 20 × 1.477 = 29.54 = 29.5 dB.
equivalent flat bottom hole
far zone
flow
focused probe
frequency
fundamental frequency
The flat bottomed hole of a diameter such that, at a similar depth in a similar material
to that of a discontinuity under evaluation, it most nearly provides equal reflectivity to
that of discontinuity under similar test conditions.
The region in an ultrasonic beam in which the intensity is inversely proportional to the
square of the distance (see Fig. 2.7).
See defect.
A probe constructed so that ultrasonic waves can be converged to a point or line focus.
See acoustic frequency.
The lowest acoustic frequency which will cause a condition of resonance to be
established in a given material of given thickness.
NOTE: This fr equency wil l be such that the wavelength in the given material is equal to twice the
given thickness.
gain
gain control
gap scanning
gate
ghost echo
grass
harmonic frequency
The amount by which the electrical signal from the ultrasonic transducer is amplified.
An instrument control which enables the gain of a receiver to be adjusted; gain controls
are usually calibrated in decibels.
A form of scanning in which the probe carrier follows the contour of the object under
test, but the probe, whilst not in direct contact with its surface, is coupled to it through
a layer or jet of liquid which is maintained between the surfaces of the probe and the
object.
A selected transit time range from which signals may be extracted for further processing.
The display of remanent reflections resulting from a previously transmitted pulse due to
the use of too high a pulse repetition frequency.
Background indications in A-scan presentation arising from material characteristics and/or
equipment noise.
Any acoustic frequency, higher than the fundamental frequency, which will cause a
condition of resonance to be established in a given material of given thickness.
NOTE: All simple mult iples of fundamental fr equency, i.e. 2, 3, 4, . . . . . . . . . . . . n times the
fundamental fr equency are harmonic frequencies.
horizontal linearity
immersion probe
The relationship between horizontal distances along the time base and actual distances
travelled by the acoustic beam.
A probe especially constructed for use fully immersed in a liquid.
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Term
Defi niti on
immersion testing
A testing method in which the product under test is wholly or partially immersed in a
liquid.
The use of a surface to redirect an ultrasonic beam.
A signal in A-scan presentation which indicates the instant at which the pulse is applied
to the transmitting crystal.
The boundary between two media of different acoustic impedance.
A device which will trigger or commence the display trace at a selected signal received
after the initial pulse. This facility is used in immersion testing.
A form of wave motion which is propagated in thin material, the velocity of which is
dependent on the product of frequency and material thickness.
Electronically generated pulses presented on a time-base sweep.
The phenomenon whereby a wave of a given mode of propagation generates waves of
other modes of propagation by reflection or refraction.
An electronic device for processing signals from a gated portion of the presentation.
The repeated reflection of an ultrasonic pulse between surfaces or discontinuities in a
body.
The region in an ultrasonic beam subject to variation of intensity due to interference
effects. The length of the region is governed by frequency, probe diameter and material
characteristics (sec Fig. 2.7).
Acoustic or electrical interference arising from the amplifier, the probe or other sources.
A probe so constructed that the beam axis is normal to the incident surface.
The usable remaining gain expressed in decibels, when working at a given test sensitivity,
i.e. when displaying as a signal of given height an echo from a given reflector.
indirect scan
initial pulse indication
interface
interface triggering
interface gating
Lamb wave
marker
mode transformation
monitor
multiple echo
near zone
noise
normal probe
overall system gain
NOTE: This may not be the total apparent amplif ication remaining since the intr oducti on of
electr onic or probe noise to the display may li mit amplif ication to be used.
probe
probe index
probe shoe
pulse
pulse echo method
pulse envelope
pulse length
pulse duration
An electro-acoustic device used for generating and/or receiving ultrasonic waves.
The point on a shear wave or surface wave probe through which the axis of the emergent
beam passes.
Material interposed between a probe and test specimen to improve acoustic contact, to
resist wear or as part of the construction of an angle probe.
A short wave-train produced on each excitation of an electro-acoustic transducer.
A method by which a discontinuity is detected and evaluated by reflection of pulses.
The shape of the curve of transmitted pulse obtained when amplitude is plotted against
time (see Fig. 2.8).
The interval, expressed in cycles, in microseconds, or the distance expressed in
wavelength, between the leading and trailing edges of the pulse envelope, measured at
10 percent of the rise and fall of the envelope (see Fig. 2.8).
Fig. 2.8. PULSE ENV ELOP ES
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Term
Defi niti on
pulse repetition frequency
The number of times per second an electro-acoustic transducer is excited to produce a
pulse of acoustic energy (often referred to as ‘p.r.f.’)
The frequency distribution in a pulse as a function of energy (see Fig. 2.9).
pulse spectrum
Fig. 2.9. TYP ICAL SP EC TRUM OF PULSE GEN ER ATED BY A DA MPED
BA RIUM TITANA TE 5 MHz TRA NS DU CE R
Rayleigh wave
recognition envelope
reference block
reference echo
reference level
reference sensitivity
resolution
scale expansion
scanning
sensitivity
shear wave
shear wave probe
single probe
skip distance
See surface wave.
A group of echo signals obtained during a particular probe movement and from which the
shape of a discontinuity may be inferred.
A piece of material used as an aid to the interpretation of results (see also calibration
block).
An ultrasonic echo received from a known reflector.
The level at which amplitudes of indications are assessed.
Instrument settings relating to a reference echo of reproducible amplitude with which
other instrument settings relating to a discontinuity echo are compared.
The ability of an ultrasonic flaw detection system to give separate indications of
discontinuities having nearly the same range and/or lateral position with respect to the
beam axis.
The spreading of the time base interval to enable echoes from a selected range to be
displayed.
The procedure of searching for discontinuities by movement of acoustic wave probes over
the test surface which results in changes in the acoustic waves within the test object.
The characteristics of an ultrasonic instrument and probe combination which determine
the minimum usable input signal, i.e. the least input which after amplification and display
satisfies certain specified requirements such as signal height.
A form of wave motion in an elastic medium in which the particle displacement is normal
to the direction of propagation.
A probe for generating or receiving shear waves.
A probe incorporating one crystal acting as a transmitter and/or a receiver of ultrasonic
waves.
The distance between successive points of impingement of the beam axis on the entry
surface, after reflection from the opposite surface (see Fig. 2.10).
Fig. 2.10. SKIP DISTANC E
specular reflection
spurious echo
suppression
Reflection of an ultrasonic beam such that the angle of reflection is equal to the angle
of incidence.
An indication not obviously associated with a discontinuity or boundary.
The reduction of the dynamic range of a display by electronic means (see Fig. 2.11).
NOTES:
1. Suppression is commonly used to prevent small, unwanted received signals, e.g. grass’, from
being displayed and thus to improve the clarit y of the display of received signals of signifi cant
amplit ude. In such cases, it is oft en referr ed to as ‘reject’ or ‘grass-cutti ng’. In some cases the
type of suppression incorporated serves as a means of increasing the dif ference in displayed
heights of received signals of small amplit ude diff erences.
2. Suppression may be achieved in two ways as shown in Figs 2.11(b) and 2.11(c). It should be
noted that whil e both of these methods may be used as a means of ‘r eject’ or ‘grass-cutti ng’ only
the method of Fig. 2.11(b) wil l serve to magnif y the amplit ude diff erence of received signals.
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Fig. 2.11 (a). NO SUPPRESSION,
DISP LAYE D SIGNA LS LINE AR
Fig. 2.11 (b). SU PP RE SS ION
INTRODUC ED , DYN AMIC
RA NGE RE DU CE D AND
LINE AR ITY DE STROYE D
Suppression is achieved by changing
the amplif ier characteristics so that the
amplif ication applied to received
signals of small amplitude is less than
that applied to received signals of
larger amplitude.
Fig. 2.11 (c). SU PP RE SS ION
INTRODUC ED , DYN AMIC
RA NGE RE DU CE D BUT
DISP LAYE D SIGNA LS RE MAIN
LINE AR
Suppression is achieved by total
rejection fr om the display of received
signals below a predetermined
amplit ude.
Term
Defi niti on
surface wave
A wave propagated in the surface layer of an object and confined to a depth of
approximately one wavelength.
A probe for generating and/or receiving surface waves.
A method in which the quality of an object is assessed by the intensity of the ultrasonic
energy incident on a receiving probe after the energy has been transmitted through the
object.
A display generated in such a way that the distance along the horizontal axis is
proportional to time.
A device used to convert electrical energy into acoustic energy or vice versa.
Reduction of acoustic energy which occurs on transmission across a boundary between
two media.
The point on the time base which corresponds to the instant at which acoustic energy
enters the object under test.
A probe incorporating two acoustically separated crystals in a single housing, one of
which acts as a transmitter of ultrasonic waves and the other as a receiver.
The development of an interference pattern between a reflected wave and a reference
wave, to provide three-dimensional information.
Spectral analysis of a reflected wave.
An angle probe so constructed that the angle of the axis of the transmitted ultrasonic
beam can be varied in a known manner.
surface wave probe
through transmission method
time base
transducer
transfer loss
transmission point
twin probe
ultrasonic holography
ultrasonic spectroscopy
variable angle probe
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Term
Defi niti on
velocity of propagation
The common value of the phase and group velocities of an ultrasonic wave propagating
in a non-dispersive medium, i.e. any medium of thickness substantially greater than the
transmitted wavelength.
The relationship between the amplitudes of an indication in A-scan presentation and the
magnitude of the corresponding received signals.
An imaginary surface connecting all points of the same phase in a wave propagating in
a medium.
A series of pressure minima and maxima resulting from the superposition of waves of
different frequencies.
The distance in the direction of wave propagation, between successive wave fronts of
identical phase.
A succession of ultrasonic waves in a medium arising from a common source and
propagating along a common path.
A prism, usually of plastics material, placed in acoustic contact between a crystal and the
test object which causes ultrasonic waves to propagate at a known angle in that object.
A mechanical device incorporating one or more crystals mounted inside a liquid filled
flexible tyre.
A quantitative definition of the controllable variables which affect sensitivity, usually
reported by reference to the signal height from a reference block or calibration block and
related instrument settings.
vertical linearity
wave front
wave interference
wavelength
wave-train
wedge
wheel probe
working sensitivity
COPYRIGHT
AS 1929—1981
14
SECTION 3. TERMS USED IN ELECTROMAGNETIC TESTING
Term
Defi niti on
absolute coil
absolute coil system
A coil(s) that respond(s) to all electromagnetic properties of the product under test.
A coil assembly which measures changes in current flow independently of any reference
standard.
Unwanted signals produced as a result of variations in quality or dimensions which are
not associated with defects, or by signals resulting from variations in the method of
inspection such as different inspection speeds or misalignment of the coil assembly or
position in relation to the product under test.
An alternating current bridge method in which variations in the product under test are
sensed in terms of the bridge out-of-balance signal.
An injected signal which is adjusted to be equal in frequency and amplitude but opposite
in phase to a signal produced by the test.
An arrangement of one or more turns of a conductor.
A combination of primary and secondary coils.
A coil assembly which measures changes in current flow between two separate test
pieces.
For a body of uniform shape, the depth below the surface at which the current density is
one-third of its value at the surface. (Frequently used in eddy current testing to describe
the greatest depth at which eddy currents are sufficiently strong for the detection of
discontinuities).
A coil assembly used in eddy current testing in which two adjacent portions of a test
piece are compared.
The ability to distinguish between signals, usually between signals from discontinuities
which may differ in their nature.
The effect produced by the relative movement between the primary coil and the product
under test.
A local current induced in a conducting body by an applied alternating or varying
magnetic field.
The change in eddy current distribution caused by abrupt product dimensional change such
as the edge of a plane surface or the end of a rod or tube.
background noise
bridge unbalance method
bucking signal
coil
coil assembly
comparative coil system
depth of penetration
differential coil system
discrimination
drag effect
eddy current
edge-effect
end-effect
NOTE: The resulti ng distorted magnetic field may prohibit the detecti on of discontinuiti es at or
adjacent to these areas.
effective coil diameter
encircling coil
fill factor
gate
IACS
impedance
impedance analysis
impedance diagram
internal coil
lift-off effect
magnetic field
magnetic field strength
magnetic flux
magnetic flux density
The diameter of a theoretical cylindrical coil having the same electromagnetic effect as
the test coil.
A coil assembly which surrounds the product under test.
A measure of the special relationship between the coil and the product under test. It is
the square of the ratio of the product diameter to the diameter of the encircling coil(s).
Alternatively it is the square of the ratio of the product bore or hole diameter to the
diameter of an internal probe.
A selected transit time range from which signals may be extracted for further processing.
The International Annealed Copper Standard, an international standard of electrical
conductivity.
The ratio of the r.m.s. electromotive force in a circuit to the r.m.s. current which is
produced thereby. (The impedance, which has resistive and reactive components,
determines the amplitude and phase of the current relative to a given applied alternating
voltage.)
Methods used to analyse changes in the resistance and reactance to the secondary or
search coil which enable geometrical and/or metallurgical conditions to be deduced.
A graph showing the reactive and resistive components of a coil as functions of, for
example, frequency, conductivity, permeability or dimensions.
A coil assembly which is surrounded by the product under test.
The change in impedance of a coil which takes place when it is moved away from the
product under test.
The space in the neighbourhood of an electric current or of a permanent magnet,
throughout which the forces due to the current or magnet can be detected.
The measured intensity of a magnetic field at a point, usually expressed in amperes per
metre (A/m).
The surface integral of the magnetic field intensity normal to the surface. The unit of
magnetic flux called the weber is the flux which, linking a circuit of one turn produces
in it an electromotive force of one volt as it is reduced to zero at a uniform rate in one
second.
The condition which arises when a magnetic flux of one weber is distributed uniformly
over an area of one square metre where the area is perpendicular to the direction of
magnetic flux. The unit is the tesla.
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Term
Defi niti on
magnetic saturation (a.c.)
The condition reached in a ferromagnetic material subjected to an a.c. magnetic field
when the incremental permeability reaches unity during part of each half cycle.
The condition reached in a ferromagnetic material subjected to a d.c. magnetic field when
the incremental permeability is equal to unity.
Instrumentation methods used to analyse signals from the secondary or search coil(s) after
the separation of individual interpretation of frequencies or frequency bands in the
modulating envelope of the carrier frequency signal.
A device used to signal changes in eddy current response which is outside specified limits
for the product under test. It also signals changes when the test equipment operates
outside prescribed limits.
An unwanted electrical signal in the test equipment which may interfere with the normal
response and processing of a desired signal.
That frequency which provides the highest signal-to-noise ratio obtainable for detecting
an individual property such as conductivity, crack or other discontinuity in the product
under test.
magnetic saturation (d.c.)
modulation analysis
monitor
noise
optimum frequency
NOTE: Each type of discontinuity in a given product may have it s own optimum fr equency.
paralysis
phase analysis
phase angle
The condition of an amplifier that is temporarily inoperative, e.g. arising from
overdriving.
An instrumentation method which uses phase angle changes to discriminate between
geometrical and/or metallurgical variations in the product under test.
The angular equivalent of the time displacement between corresponding points on two
sine waves of the same frequency.
NOTE: The phase angle is changed by variati ons in geometr ical and metallurgical condit ion of the
product under test.
phase shift
phase-sensitive system
phasing out
phasor
primary coil
probe coil
Q factor
recovery time
reference standard
reference piece
resolution
response time
search coil
secondary coil
shielded coil
A change in the phase relationship between two alternating quantities of the same
frequency.
A system in which the output signals are dependent on the phase relationship between an
input and a reference voltage.
The suppression of drag effects, and other unwanted signals by adjustment of the setting
of the phase of the reference voltage.
A representation of the amplitude and time relationships between alternating quantities.
The coil which induces alternating magnetic flux in the product under test.
A coil assembly which does not encircle the product under test.
The numerical ratio between the reactance and the resistance of the winding in a coil at
the operating frequency.
The time required for a test system to return to its original state after having received a
signal.
A portion of material of the same geometrical and metallurgical characteristics as the
product under test which may or may not contain natural or artificial discontinuities.
The clarity with which electrical signals may be separated from each other.
The time delay between the sensing of a discontinuity by a search coil and its indication.
Any type of eddy current coil or sensor.
The coil which detects the magnetic flux induced by the primary coil in the product under
test.
A coil fitted with a magnetic or non-magnetic shield in order to limit the distribution of
eddy current in the product under test.
NOTE: The coil assembly may be shielded both magneti call y and electrostatically.
signal-to-noise ratio
skin effect
suppression
surface coil
test speed
wobulation
The ratio of the amplitude of a signal arising from a discontinuity to the amplitude of the
average back-ground noise signal.
The phenomena wherein the depth of penetration of an alternating electric current into
a conductor decreases as the frequency of the current is increased. At very high
frequencies, the current flow is restricted to an extremely thin outer layer of the
conductor.
The action taken to ensure that unwanted signal are prevented or at least reduced.
A probe coil shaped to conform to the geometry of the product under test.
The relative movement between the coil assembly and the product under test.
An effect which produces variations in output signals which arise from variations in
dimensional clearance between an encircling coil and the surface of the product under
test.
COPYRIGHT
AS 1929—1981
16
SECTION 4. TERMS USED IN MAGNETIC PARTICLE TESTING
Term
Defi niti on
alternating current magnetization
background
Magnetization by the magnetic field induced when alternating current is flowing.
The general appearance of the test surface on which indications of discontinuities are
sought.
See contrast aid.
Near ultraviolet radiation (320 nm to 400 nm) used for exciting fluorescence.
A filter which suppresses visible light and ultraviolet radiation other than black light.
Local overheating of the component at the electrical contact area arising from high
resistance or from the generation of an arc.
The fluid in which magnetic particles are suspended to facilitate their application.
Magnetization which establishes a magnetic field around the periphery of a component.
The agglomeration of magnetic particles in a fluid, occasioned by an undesirable
contaminant.
A method of magnetization in which part or the whole of the component is encircled by
a current-carrying coil. (The use of the term is usually restricted to instances in which
the component does not form part of a continuous magnetic circuit for the flux
generated.)
Fluid containing coloured magnetic particles other than black.
A test for demagnetization carried out by placing the component in specified positions
in relation to a magnetic compass needle and ascertaining whether the consequent
deflection exceeds a specified maximum.
The electrodes between which the magnetizing current flows.
Metal pads, usually of copper braid, placed on electrodes to give good electrical contact,
thereby preventing damage to the test surface.
See sustained magnetization method.
The difference in reflectivity or coloration between the test surface and any
discontinuities indicated by the magnetic particle.
Any coating or film applied to a surface to improve contrast by providing more suitable
background.
That part of an electromagnetic circuit which is within the winding.
Magnetic particle testing equipment supplying alternating, rectified alternating or direct
current for magnetizing components by the current flow method.
A method of magnetizing by passing a current through a component via electrodes, i.e.
prods, contact heads or clamps. The current may be alternating, rectified alternating or
direct.
Magnetic particle testing equipment which is designed for the induced current flow
method.
The process whereby a magnetized body has its degree of magnetism substantially
reduced.
A coil carrying alternating current used for demagnetization.
A function of the length/diameter ratio of a given component which can be calculated for
components having the shape of ellipsoids of revolution but has to be measured
experimentally for other shape.
Indications that are not clearly defined, e.g. indications of sub-surface discontinuities.
An electric current flowing in one direction only and sensibly free from pulsation.
Magnetization by a magnetic field induced when direct current is flowing.
The application of magnetic particles without the use of a carrier fluid.
A factor depending on the magnetic permeability (µ) and on a factor N/4π (called the
demagnetization factor) where N is the constant of the proportionality.
A conductor by means of which a current passes into or out of the component under test.
Magnetization by a current flow of very brief duration.
Property of emitting light as the result of, and only during absorption of, radiation from
some other energy source.
A detecting medium consisting of a carrier fluid containing a dispersion of coated
magnetic particles which fluoresce under black light.
The condition which arises when a magnetic flux of one weber is distributed uniformly
over an area of one square metre where the area is perpendicular to the direction of
magnetic flux. The SI unit is the tesla.
A reference device used for checking the presence and/or the direction of a magnetic field
by placing the device in contact with the component under test.
The depth to which a magnetic flux is effective in a component.
background paint
black light
black-light filter
burning (arcing)
carrier fluid
circular magnetization
coagulation
coil method
coloured magnetic ink
compass test
contact heads
contact pads
continuous method
contrast
contrast aid
core
current flow equipment
current flow method
current induction equipment
demagnetization
demagnetizing coil
demagnetizing factor
diffuse indications
direct current (d.c.)
direct current magnetization
dry powder method
effective magnetic-permeability
(µef f)
electrode
flash magnetization
fluorescence
fluorescent magnetic ink
flux density
flux indicator
flux penetration
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Term
AS 1929—1981
Defi niti on
furring
Build-up of magnetic particle due to excessive magnetization of the component under
test.
induced current flow method
A method of magnetizing in which a current is induced in a ring component by the
influence of a fluctuating magnetic field which links the component.
longitudinal magnetization
Magnetization in which lines of flux in a component are essentially parallel to its
longitudinal axis.
magnetic circuit
The complete closed path followed by any group of lines of magnetic flux.
magnetic field
The space in the neighbourhood of an electric current or of a permanent magnet,
throughout which the forces due to the current or magnet can be detected.
magnetic field distribution
The distribution of field strength in a magnetic field.
magnetic field leakage
The loss of magnetic field strength due to discontinuities and changes in section in a
magnetic circuit.
magnetic field strength
The measured intensity of a magnetic field at a point, usually expressed in amperes per
metre (A/m).
magnetic flow equipment
Magnetic particle testing equipment consisting of an electromagnet or permanent
magnet in series with a magnetic yoke having an adjustable gap in which the whole or
part of the component is inserted.
magnetic flow method
A method of magnetization in which the component or portion of it closes the magnetic
circuit of an electromagnet or permanent magnet.
magnetic flux
The surface integral of the magnetic field intensity normal to the surface. The unit of
magnetic flux called the weber is the flux which, linking a circuit of one turn, produces
in it an electromotive force of one volt as it is reduced to zero at a uniform rate in one
second.
magnetic flux density
The condition which arises when a magnetic flux of one weber is distributed uniformly
over an area of one square metre where the area is perpendicular to the direction of
magnetic flux. The SI unit is the tesla.
magnetic ink
A detecting medium consisting essentially of magnetic particles in a carrier fluid.
magnetic leakage field
The magnetic field, external to a component and in proximity to a discontinuity, which
is detectable by magnetic particles.
magnetic particle testing equipment Equipment providing, essentially, current or flux for the purpose of magnetic particle
testing, and usually, facilities for holding components of varying dimensions, and for
adjusting and reading the magnetizing current.
magnetic permeability (µ)
The ratio of the magnetic induction to the external magnetic field causing the induction.
magnetic poles
The points in a magnet which are the apparent seat of the external magnetic field.
magnetic powder
Magnetic particles in dry powder form, of suitable shape and size.
magnetic saturation
The stage at which any increase in the magnetic field applied to a magnetized
component fails to show any significant increase in the magnetic flux in that
component.
magnetic writing
Unwanted indications arising from random local magnetization.
magnetization
The process of rendering ferromagnetic materials capable of attracting or repelling other
ferromagnetic materials.
particle content
The apparent volume ratio of magnetic particles to carrier fluid in magnetic ink.
peak current
The maximum instantaneous value of the direct or periodic current obtained during
excitation. Usually, with a d.c battery source or with three-phase full wave rectified a.c
it will be approximately that indicated by the ammeter. With a.c or full wave rectified
a.c it will be √2 × the r.m.s current. With half-wave rectified a.c it will be
approximately 2√2 × the r.m.s current.
NOTE: Ammeters fit ted to half- wave equipment are usually calibrated to take account of the
doubli ng factor (× 2) and therefore indicate equivalent r.m.s values.
prods
profile pole pieces
residual magnetism
residual magnetization method
settling time
split coil
surface field
sustained magnetization method
Sutherland flask
Hand-held electrode attached to wander cables to transmit the magnetizing current from
the source to the component under test.
Pole pieces consisting of separately adjustable magnetic elements for taking up irregular
contours.
The magnetism remaining in a component when, after initial magnetization, the
magnetizing force is reduced to zero.
Magnetic particle testing in which the indicating medium is applied after removal of
the magnetizing force.
The time allowed for settlement of magnetic particles in a sample of magnetic ink prior
to the assessment of particle content.
A single or multi-turn coil constructed with plug connections to allow it to be opened
for positioning over components having no free ends for normal coil access.
The magnetic field at the surface of the component under test.
A method of magnetic particle testing in which the indicating medium is applied during
magnetization.
A flask wed for measuring the apparent proportion of solids separating under gravity
from a known volume of magnetic ink. The ungraduated upper portion, shaped like an
COPYRIGHT
AS 1929—1981
Term
threading bar method
threading coil method
yoke
18
Defi niti on
inverted pear, is constricted at the top to receive a stopper and blended at the bottom into
a graduated tube of small uniform section.
A method of magnetization in which a current-carrying bar, cable or tube is passed
through a bore or aperture in a component under test.
A method of magnetization in which a current carrying cable is threaded, one or more
times, through a bore or aperture in a component under test.
That piece of ferro-magnetic material of an electro-magnet, not surrounded by windings,
forming a fixed part of the magnetic circuit and serving to complete that circuit.
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SECTION 5. TERMS USED IN PENETRANT TESTING
Term
Defi niti on
background
The general appearance of the test surface on which indications of discontinuities are
sought.
Coloration remaining after incomplete removal of dye penetrant from the test surface.
Fluorescence remaining after incomplete removal of a fluorescent penetrant from the test
surface.
Near ultraviolet radiation (320 nm to 400 nm) used for exciting fluorescence.
A filter which suppresses visible light and ultraviolet radiation other than black light.
A fluid which acts as a carrier for active additives.
Fluids employed to remove oil and grease from components.
A dry powder, or an aqueous or solvent suspension of powder which assists in
withdrawing a penetrant retained in discontinuities to enhance the discontinuity
indication.
The time between the application of the developer and subsequent viewing.
The loss of fluid as a result of carry-over.
A penetrating fluid containing a dye which is visible under normal light (see also
penetrant).
Fluids which when mixed with a particular type of penetrant forms an emulsion thus
rendering the penetrant water washable.
Property of emitting light as the result of, and only during absorption of, radiation from
some other energy source.
A penetrant used to reveal surface discontinuities which become visible when irradiated
with black light.
A fluid which is capable of being drawn into surface discontinuities by capilary action
and which remains there after excess penetrant has been removed from the test surface.
Any means employed to remove excess penetrant.
The time during which the penetrant is in contact with the test surface.
Penetrant which must be treated with an emulsifying agent to render it water washable.
The time in which the penetrant on the component is in contact with the emulsifier.
An emulsifying agent applied to a non-water washable penetrant in the post-emulsifiable
penetrant method.
The extinction of fluorescence by means other than the removal of the exciting radiation,
e.g. the action of strong oxidizing agents or changes in temperature or concentration.
Test pieces containing controlled artificial discontinuities or natural discontinuities, used
for checking the efficiency of the penetrant testing method and materials.
A penetrant which must be removed by a suitable solvent.
An intentionally cracked test panel having separate areas for the application of different
penetrants so that a direct comparison can be obtained.
A penetrant with suitable emulsifying agents incorporated to render it directly water
washable.
background coloration
background fluorescence
black light
black-light filter
carrier fluid
degreasing fluids
developer
development time
drag-out
dye penetrant
emulsifier
fluorescence
fluorescent penetrants
penetrant
penetrant removal
penetration time
post-emulsifiable penetrant
post-emulsification time
post-emulsifier
quenching of fluorescence
reference pieces
solvent removable penetrant
standard cracked test panel
water washable penetrant
COPYRIGHT
AS 1929—1981
20
SECTION 6. TERMS USED IN RADIATION TESTING
Term
Defi niti on
absorbed dose (D)
The quantity of radiation or energy absorbed and is the quotient of dE by dm, where dE
is the energy imparted by ionizing radiation to the matter in a volume element and dm
is the mass of the matter in that element, i.e. D –
absorption
activity
source strength
anode
attenuation
autoradiography
back scatter
beam angle
beam divergence
The SI unit of absorbed dose is the gray (Gy).
The reduction in intensity of a beam of radiation during its passage through matter due
to photo-electric absorption and pair production only (see also attenuation).
The number of radioactive disintegrations of a given source occurring per unit time.
The SI unit is the becquerel (Bq).
The positive electrode of an X-ray tube carrying the target from which X-rays are emitted
(see Fig. 6.7).
The reduction in intensity when a beam of ionising radiation passes through matter.
Production of an image by the photographic recording of natural radiation.
That part of the scattered X-radiation or gamma radiation which is transmitted at an angle
of more than 90 degrees in relation to the direction of the incident beam.
The angle between the central axis of the radiation beam and the plane of the
radiographic film (see Fig. 6.1).
The angle of the beam of radiation as it emerges from the X-ray tube or gamma-ray
exposure container (see Fig. 6.1).
Fig.
6.1. BE AM DIVER GE NC E AND BE AM AN GLE
becquerel (Bq)
The SI unit of activity, equal to one disintegration per second.
NOTE: The becquerel replaces the curi e (Ci).
1 curie (Ci) = 3.7 × 1010 becquerel (Bq)
= 37 gigabecquerel (GBq).
betatron
blocking medium
broad beam
build-up factor
cassette
cathode
characteristic curve
sensitometric curve
characteristic radiation
cine-radiography
collimation
constant potential circuit
continuous spectrum
A source of high energy X-rays in which electrons are accelerated in a circular orbit by
means of magnetic induction.
A material used adjacent to a product during radiography to reduce the effect of scattered
radiation, and/or minimize the effect on section differences on radiographic exposure.
An uncollimated beam containing scattered radiation as well as the primary beam.
The ratio of the intensity of the total radiation reaching a point to the intensity of the
primary radiation reaching the same point.
A light-tight container for holding a radiographic film during exposure.
The negative electrode of an X-ray tube carrying the filament and focusing cup (see
Fig. 6.7).
A curve showing the relation between the logarithm to the base 10 of the relative exposure
and the photographic density of a film (see Fig. 6.2). Film A is said to be faster than
film B. The gradient of film B is greater than that of film A and this is indicative of
greater contrast, i.e. it produces a greater density range for the same difference in
exposure.
X-radiation consisting of discrete wavelengths which are characteristic of the emitting
material (see Fig. 6.3).
The production of a series of radiographs which can be viewed rapidly in sequence, thus
creating an illusion of continuity.
The production of a near parallel beam of radiation by use of a slit or aperture in an
absorbing material.
A circuit which is arranged to supply a substantially constant potential across an X-ray
tube.
The plot of the relation between wave length and relative intensity of a beam of X-rays
(see Fig. 6.3)
COPYRIGHT
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AS 1929—1981
Fig. 6.2 CHA RA CTER ISTIC (SEN SITOMETRIC) CU RV ES
Fig. 6.3 CONTINU OUS SPE CTRU M AND CH AR AC TERISTIC RA DIATION
Term
Defi niti on
contrast indicator
A radiographic arrangement whereby variations in densities in a radiograph can be
assessed against known values.
An X-ray tube in which the source of the bombarding electrons is a heated filament in
the cathode.
The SI unit of exposure. It replaces the roentgen (R).
1 R=2.58 × 10 C/kg.
See becquerel.
The process by which the eye adapts itself to a lower level of ambient illumination when
entering a darkened room.
Decrease of activity due to radioactive disintegration.
Coolidge tube
coulomb per kilogram (C/kg)
curie
dark adaptation
decay (radioactive)
NOTE: The rate of decay is usually expressed in terms of half- li fe activit y (see also half -l if e).
decay curve
defect sensitivity
densitometer
density (photographic)
development (photographic)
dichroic fog
diffraction
diffraction mottle
discontinuity sensitivity
The activity of a radioactive source, measured in becquerels, plotted against time.
The minimum size of a discontinuity, considered to be a defect, which can be detected
under specified conditions.
An instrument for measuring light transmission and/or reflection density of film, plate or
paper.
The degree of blackening of a radiographic film expressed as the logarithm to base 10
of the opacity of the film, that is, ratio of intensity of incident light to the intensity of
transmitted or reflected light.
The conversion of a latent image into a visible image.
Fog arising from the deposition of a very thin layer of finely divided silver on an
emulsions which, when examined in white light, appears in two colours, red by
transmission and green by reflection.
The phenomenon of the preferential scattering of a beam of radiation in certain directions
arising from the interference between waves scattered by different elements of volume
in the medium.
A mottle superimposed on a radiographic image due to the diffraction of incident
radiation.
The capability of a radiograph to display the image of a particular discontinuity.
NOTE: This property is usually expressed quantit atively as the minimum size of a disconti nuit y
which can be seen under specifi ed condit ions.
COPYRIGHT
AS 1929—1981
22
Term
Defi niti on
dose
A general term denoting the quantity of radiation or energy absorbed.
NOTE: For the purpose of this standard the word ‘dose’, when used alone is a convenient synonym
for dose equivalent.
dose equivalent (H)
dose rate
The product of ‘absorbed dose’ (D), quality factor (Q) and any other relevant modifying
factors (N), i.e. H = DQ N. The SI unit for dose equivalent is the sievert (Sv).
A monitoring device used for measuring or evaluating the absorbed dose, exposure, or
similar radiation quantity.
The rate at which radiation is delivered.
dose rate meter
dual-focus tube
dynamic range
An instrument for measuring radiation dose rate.
An X-ray tube with a choice of two different sizes of focal spot.
The difference between the two extremes of correct exposure (see also exposure latitude).
dosimeter
NOTE: The term has a slightly dif ferent meaning in relati on to healt h physics.
NOTE: The dynamic range is set by the minimum acceptable gradient and by the maximum readable
densit y.
electron radiography
equalizing filter
equilibrium half-value layer
(or terminal)
equivalent sensitivity (of an IQI)
exposure container
exposure chart
exposure fog
exposure latitude
A method of radiography in which a beam of electrons passes through a test object and
is recorded on film. Alternatively, a beam of X-rays is incident on the test object and the
electrons emitted from the surface are recorded on film.
A device to equalize the intensity across the primary X-ray beam.
The greatest thickness of materials required to reduce the intensity of a polychromatic
beam of radiation, passing through an absorber, by a factor of two.
Is the equated value of sensitivity of the radiograph when measured by another type of
image quality indicator.
A device for housing radioisotopes which provides protection against radiation and
permits controlled exposure of radiation.
A chart on which is plotted one or more curves which indicate exposures for specified
product thicknesses.
Fog arising from any unwanted exposure of a film, to ionizing radiation or light, at any
time between manufacture and final fixing.
The exposure latitude relates the ability of a film to accommodate variations in density
occurring as a result of differences in thickness.
NOTES:
1. Fig 6.4 refers to the characteri stic curve of a fil m the dynamic range a of which is set by the
minimum acceptable gradient A and the maximum readable fi lm densit y B.
2. The useful range of eff ecti ve exposure for the test object is assumed to be b, the extremiti es of
which are determined by the thickest and thinnest secti ons
The exposure lati tude is given by the ratio—
Expressed logari thmicall y this is equal to a – b = c.
a = Dynamic range
b = Useful range of effective exposure
c = Exposure latit ude
Fig. 6.4. EXP OS UR E LATITUD E
COPYRIGHT
23
AS 1929—1981
Term
Defi niti on
filament
film badge
The source of electrons in a Coolidge type cathode tube (see Fig. 6.6).
A film contained within a special holder worn by personnel in order to assess the
radiation to which the wearer has been exposed.
A flexible transparent or translucent support for the photographic emulsion.
The time required for the first stage of fixing during which the unsensitized silver halide
is removed as indicated by the disappearance of the whiteness of the film.
The property of a film to record differences in density in relation to radiation intensity.
It depends on the gradient of the characteristic curve at a given density (see Fig. 6.2).
The operations necessary to transform a latent image into a permanent visible image.
A measure of the exposure required to produce a given density on a photographic
emulsion under any given set of conditions (see Fig. 6.2).
See inherent unsharpness.
A layer of absorptive material interposed in the path of radiation in order to reduce
selectively the intensity of the lower energy radiation.
The chemical removal of unexposed silver halides from emulsion after development.
Radiography for the purpose of examining transient effects, such as moving objects in
which the radiation intensity is relatively high and the exposure time is relatively short.
A suitably mounted layer of material which fluoresces in the visible region of the
spectrum under the action of X-rays or gamma rays.
Photography of a fluoroscopic image.
A support base to which is attached thin lead foil coated with a fluorescent material.
The process by which a single screen containing fluorescent material is irradiated with
X-rays or gamma rays giving a pattern of visible light corresponding to the intensity of
incident radiation.
The area on the surface of the anode of an X-ray tube on which the electron stream
impinges and from which the primary beam of X-rays is emitted.
A general term used to denote any increase in the density of a film arising from unwanted
chemical reactions during manufacture, storage or processing.
Rectification which allows current to flow during each half cycle of an alternating supply.
Electromagnetic radiation emitted in the process of nuclear transition or particle
annihilation.
Radiography using a gamma-ray source.
A quantity of matter emitting gamma-radiation which is suitable for radiography (see
sealed source).
Unsharpness caused by penumbra geometrically related to a finite source size and sourceto-film distance.
The slope of a characteristic film curve at a specified density (see Fig. 6.2).
A visual effect due to the random distribution of groups of silver grains in the fixed
emulsion layer.
The SI unit of absorbed dose of ionising radiation, equal to the joule per kilogram (J/kg).
film base
film clearing time
film contrast
film processing
film speed
film unsharpness
filter
fixing
flash radiography
fluorescent screen
fluorography
fluorometallic screen
fluoroscopy
focal spot
fog
full-wave rectification
gamma radiation (or rays)
gamma radiography
gamma ray source
geometric unsharpness
gradient (Gd)
graininess
gray (Gy)
NOTE: The gray replaces the rad (rad).
I Gy = 100 rad.
half-life
half-value layer (HVL )
The time required for the activity of a radio-nuclide to be halved.
The thickness of a specified substance which, when introduced into the path of a given
beam of radiation, reduces the intensity of radiation by a factor of two (see Fig. 6.5).
NOTE: Half -value layer may be used as an indication of the quali ty of the beam or of the opacity
of the substance.
half-wave rectification
hard radiation
hardener
image definition
image forming radiation
image intensifier
See also initial half-value layer and equilibrium half-value layer.
Rectification which allows current to flow only during alternate half cycles of an
alternating supply.
Radiation of relatively high penetrating power.
A substance used to harden the gelatine in the emulsion on a radiographic film during
fixing.
The sharpness of delineation of image details in a radiograph. Generally used
qualitatively.
Radiation which is incident on the absorber and continues unaltered in energy and in
direction after passing through the absorber.
A device used when taking radiographs to render variations in X-ray intensity directly
visible.
NOTE: A higher degree of screen bri ghtness is obtained by converti ng the X-r ay photons fall ing on
the primary fluorescent screen into li ght; this in turn excit es an adjacent photoelectri c layer to emit
electr ons which are accelerated at a potenti al of approximately 20 kV to 30 kV and focused on the
fi nal viewing screen (see Fig. 6.6).
COPYRIGHT
AS 1929—1981
24
Fig. 6.5 HALF VALUE LAY ER
Fig. 6.6. IMAGE INTENS IFIER
Term
Defi niti on
image quality indicator (IQI)
A device used for judging, from the appearance of its image in a radiograph, the overall
quality of that radiograph.
The filtration of an X-ray beam by any parts of the tube or tube shield.
Image spread caused by electron or light scatter through emulsion grains in the radiographic film.
That thickness of material required to reduce the initial intensity of radiation passing
through an absorber by a factor of two.
The ratio of the exposure time required without intensifying screens to that when screens
are used, other conditions being the same.
A layer of material, which, when placed in close contact with a photographic emulsion,
adds to the radiographic effect of the incident radiation by reducing exposure time.
Radiation which produces ions.
inherent filtration
inherent unsharpness
(film or intrinsic)
initial half-value layer
intensifying factor
intensifying screen
ionizing radiation
NOTE: Ionizing radiation may be fast moving parti cles such as alpha or beta rays or be
electr omagneti c radiation such as X-ray or gamma rays.
COPYRIGHT
25
AS 1929—1981
Term
Defi niti on
IQI sensitivity
The sensitivity of a radiograph quantified in terms of the smallest IQI element seen on
the radiograph.
NOTES:
1. IQI sensiti vity is usually expressed in terms of a part icular crit ical dimension of the IQI used.
2. IQI sensiti vity should not be confused wit h disconti nuit y sensit ivit y.
latent image
line focus
linear accelerator
linac
masking
metal intensifying screen
(metal screen)
A change produced in the emulsion of a film, paper or plate by exposure to radiation and
capable of being converted into a visible image by development.
An elongated, rectangular focus so angled that the effective focus size, as viewed along
the beam axis, is smaller and approximately square, thereby permitting increased total
area loading of the target for a given effective focus size.
A straight-line particle accelerator used for the production of high energy X-rays.
The application of material which limits the area of irradiation to the region undergoing
radiographic examination.
An intensifying screen of metal foil (usually lead) which emits secondary radiation under
the influence of X-rays or gamma rays.
NOTE: Metal screens also minimize the amount of scattered radiation reaching the fil m from the
test object.
microradiography
movement unsharpness
neutron radiography
object-to-film distance
panoramic radiography
penumbra
penetrameter
pressure mark
quality factor (QF)
rad
radioactivity
radiograph
radiographic contrast
radiographic exposure
radiographic film
radiographic paper
radiographic viewer
radiography
radiology
Radiography of relatively thin sections in such a way that the resulting image is enlarged,
or is capable of being enlarged, to reveal microstructure.
Unsharpness caused by uncoordinated relative movement between radiation source, object
and film during an exposure.
The use of a beam of neutrons to examine an object by producing a graphical record or
image on sensitized film or on other recording or indicating media.
The distance from the source side of the test object to the film surface, i.e. inclusive of
object thickness.
Radiography using a centrally located source to simultaneously produce a continuous or
overlapping image or a series of discrete images on radiographic film or paper.
Blurring of a radiographic image resulting from the fact that the radiation is not from a
point source.
See image quality indicator.
A mark produced by pressure on a film which after developing results in areas of either
increased or decreased density.
A factor intended to allow for the effect on biological response of the microscopic
distribution of absorbed energy when received in small doses. Appropriate values of QF
are given below:
X-rays, λ-rays and electrons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Neutrons, protons and singly-charged particles of rest mass greater than
one atomic mass unit of unknown energy . . . . . . . . . . . . . . . . . . . . . . . . 10
Alpha particles and multiple-charged particles (and particles of unknown
charge) of unknown energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
See gray.
The property of certain nuclides of—
(a) spontaneously emitting gamma radiation;
(b) undergoing spontaneous fission;
(c) spontaneously emitting X-radiation following orbital electron capture.
A photographic image produced by ionizing radiation on a film or paper after passing
through a material (see also neutron radiograph).
The relative density or brightness between adjacent areas on an illuminated radiograph
or fluorescent screen image.
The subjection of a recording medium to radiation for the purpose of producing a latent
image. Radiographic exposure is commonly expressed in terms of milliampere minutes,
and giga becquerel minutes.
A photographic film which is usually coated on both sides with an emulsion designed for
use with X-rays and gamma rays.
Photographic type paper suitable for the production of radiographs.
Equipment incorporating a suitable area of diffuse illumination for viewing radiographs.
the brightness of the illuminated area being appropriate to the density of the radiograph.
The use of radiant energy in the form of neutrons, protons, electrons, X-rays or gamma
rays for non-destructive testing of opaque objects, in order to produce graphical records
on sensitized film.
The science and application of X-rays, gamma rays, and other penetrating ionizing
radiation.
COPYRIGHT
AS 1929—1981
26
Term
Defi niti on
radioisotope
radion uclide
reciprocity failure
An isotope which undergoes spontaneous disintegration with the emission of ionizing
radiation.
The departure from the reciprocity law of any given emulsion under specified conditions,
e.g. when salt screens are used.
A law which states that, all other conditions remaining constant, the time of exposure
required to produce a given photographic density is inversely proportional to the intensity
of the radiation.
Any method by which unidirectional voltage can be obtained from an alternating supply.
See sievert.
A net-like structure appearing in an emulsion of a radiographic film as a result of
buckling caused by difference in temperature between processing baths, or rinsing water.
A complete or partial reversal of the tones of a radiograph, generally produced by
excessive radiographic exposure.
An X-ray tube in which the target is situated near the outer end of a long tubular anode.
See coulomb per kilogram.
A source of filtered light of colour or waveband chosen to give insignificant fogging of
a particular film type at intensity levels necessary for handling and processing films in
a dark room.
An intensifying screen consisting of a substance which fluoresces in the visible or
ultraviolet region of the spectrum under the action of radiation.
Secondary radiation which is emitted in all directions.
Unsharpness caused by the use of intensifying screens or a fluorescent viewing screen.
It may result from the scatter of light by the crystals of the fluorescent layer and poor
contact between screens and films.
A radioactive source bonded or encapsulated to prevent the escape of the radioactive
material under the conditions of use for which it was designed.
The limiting amount of detail which can be seen on a radiograph. It can also be regarded
as the smallest discontinuity which can be detected under given conditions.
See characteristic curve.
The SI unit of absorbed radiation dose in biological matter equal to the absorbed dose in
grays multiplied by the quality factor (QF) of the radiation (see also dose equivalent).
reciprocity law
Bunsen-Roscoe law
rectification
rem
reticulation
reversal
rod-anode tube
roentgen
safelight
salt intensifying screen
scattered radiation
screen unsharpness
sealed source
sensitivity
sensitometric curve
sievert (Sv)
NOTE: The sievert replaces the rem.
soft-radiation
source
source shift radiography
source size (effective)
1 Sv = 100 rem.
Radiation of restively low penetrating power.
The origin of radiation.
A method for determining the depth of a discontinuity by the use of two offset sources.
The apparent dimensions as viewed along the beam axis of that portion of the source
from which ionizing radiation is emitted.
NOTE: For the purpose of calculati ng geometr ic unsharpness, the eff ecti ve dimensions must always
be taken.
source-to film-distance (SFD)
specific activity
spectral sensitivity
step wedge
stereo-radiography
subject contrast
survey meter
target
The distance from the source of primary radiation to a film set for a radiographic
exposure.
The activity per unit mass of radio nuclide (see also activity).
The variation in radiation dose with X-ray energy to produce a given film density.
A block of material in the form of a series of steps usually used for the preparation of
exposure charts.
The production of a pair of radiographs suitable for stereoscopic viewing.
The difference in radiation intensity between adjacent areas in a test object arising from
differences in attenuation characterises of those areas.
See dose rate meter.
The metal insert in the anode of an X-ray tube on which the electron beam impinges (see
Fig. 6.7).
Fig. 6.7. DIAGRAMMATIC VIEW OF PRINCIPAL COMPONENTS OF AN X-RAY
TUBE
COPYRIGHT
27
AS 1929—1981
Term
Defi niti on
tenth value layer (TVL)
The thickness of a specified substance which when introduced into a beam of radiation,
reduce the value of a specified radiation quantity by a factor of ten.
The radiography of a predetermined layer of material.
The current passing between the cathode and anode during the operation of an X-ray
tube.
A device, normally fixed to a tube shield or head, to limit the extent of the emergent
X-ray beam.
The potential difference between the anode and the cathode of an X-ray tube during
operation.
Loss of image definition (see also film unsharpness, geometric unsharpness, movement
unsharpness and screen unsharpness.)
A high voltage generator for producing X-rays usually with energies of 1 MeV to 4 MeV.
Penetrating electromagnetic radiation other than annihilation radiation originating in the
extra-nuclear part of the atom and having wavelengths much shorter than visible light.
A photographic film which is usually coated on both sides with an emulsion designed for
use with X-rays and gamma rays.
White paper coated on one side with emulsion, suitable for some purposes as an
alternative to X-ray film.
Radiography using a photoconductive plate instead of radiographic film or paper.
tomography
tube current
tube diaphragm
tube voltage
unsharpness
Van der Graff generator
X-radiation (or X-rays)
X-ray film
X-ray paper
xero-radiography
COPYRIGHT
AS 1929—1981
28
INDEX
A-scan presentation, 2
absolute coil, 3
absolute coil system, 3
absorbed dose, 6
absorption, 6
acoustic-absorption, 2
acoustic-coupling, 2
acoustic-discontinuity, 2
acoustic-frequency, 2
acoustic-impedance, 2
acoustic-impedance matching, 2
acoustic-shadow, 2
acoustic testing, 1
activity, 6
alternating-current magnetization, 4
angle of beam spread (angle of divergence), 2
angle of incidence, 2
angle of reflection, 2
angle of refraction, 2
angle probe, 2
anode, 6
area amplitude curve, 2
attenuation, 2, 6
attenuation coefficient (attenuation factor), 2
attenuator, 2
automatic gain control (AGC), 2
autoradiography, 6
AVG (diagram)—see DGS diagram, 2
B-scan presentation, 2
back echo, 2
background, 4, 5
background coloration, 5
background fluorescence, 5
background noise, 3
background paint—see contrast aid, 4
back scatter, 6
back-wall echo, 2
beam angle, 6
beam axis, 2
beam divergence, 6
beam index, 2
beam path length, 2
beam profile, 2
beam spread, 2
becquerel, 6
betatron, 6
black light, 4, 5
black-light filter, 4, 5
blocking medium, 6
boundary echo, 2
bridge unbalance method, 3
broad beam, 6
build-up factor, 6
bucking signal, 3
burning (arcing), 4
C-scan presentation, 2
calibration block, 2
carrier fluid, 4, 5
cassette, 6
cathode, 6
characteristic curve (sensitometric curve), 6
characteristic radiation, 6
cine-radiography, 6
circular magnetization, 4
coagulation, 4
coil, 3
coil assembly, 3
coil method, 4
collimation, 6
coloured magnetic ink, 4
comparative coil system, 3
compass test, 4
compression wave, 2
compression wave probe, 2
constant potential circuit, 6
contact heads, 4
contact pads, 4
continuous method—see sustained
magnetization method, 4
continuous spectrum, 6
contrast, 4
contrast aid, 4
contrast indicator, 6
Coolidge tube, 6
core, 4
corner effect, 2
coulomb per kilogram, 6
couplant, 2
critical angle, 2
cross talk, 2
crystal—(ultrasonic), 2
crystal backing, 2
crystal mosaic, 2
curie, 6
current flow equipment, 4
current flow method, 4
current induction equipment, 4
damping (probe construction), 2
dark adaptation, 6
dead zone, 2
decay method, 2
decay (radioactive), 6
decay curve, 6
decibel (dB), 2
defect, 1, 2
defect sensitivity, 6
degreasing fluids, 5
delay, 2
demagnetization, 4
demagnetizing coil, 4
demagnetizing factor, 4
densitometer, 6
density (photographic), 6
depth of penetration, 3
developer, 5
development (photographic), 6
development time, 5
DGS diagram (distance-gain-size-diagram), 2
DGS system, 2
dichroic fog, 6
differential coil system, 3
diffraction, 6
diffraction mottle, 6
diffuse indications, 4
diffuse reflection, 2
direct current (d.c.(, 4
direct current magnetization, 4
discontinuity, 1, 2
discrimination, 3
directional sensitivity, 2
distance amplitude curve, 2
dominant frequency, 2
dose, 6
dosemeter, 6
dose equivalent, 6
dose rate, 6
dose rate meter (survey meter), 6
double crystal probe, 2
double probe method, 2
drag effect, 3
drag-out, 5
dry powder method, 4
dryout time, 4
dual-focus tube, 6
dye penetrant, 5
dynamic range, 2, 6
echo (back-, boundary-, ghost-, multiple-,
reference-, spurious-), 2
eddy current, 3
eddy current testing, 1
edge-effect (end-effect_, 3
effective coil diameter, 3
effective magnetic permeability (µeff), 4
electromagnetic testing, 1
electron radiography, 6
electrode, 4
emulsification time, 5
emulsifier, 5
encircling coil, 3
equalising filter, 6
equivalent flat bottom hole, 2
equivalent sensitivity (of an image quality
indicator), 6
exposure chart, 6
exposure container (gamma ray source), 6
exposure fog, 6
exposure latitude, 6
far zone, 2
filament, 6
fill factor, 3
film badge, 6
film base, 6
film clearing time, 6
film contrast, 6
film processing, 6
film speed, 6
film unsharpness—see inherent unsharpness, 6
film viewer (radiographic viewer), 6
filter, 6
fixing, 6
flash magnetization, 4
flash radiography, 6
flaw—see defect, 2
fluorescence, 4, 5
fluorescent magnetic ink, 4
fluorescent penetrants, 5
fluorescent screen, 6
fluorography, 6
fluorometallic screen, 6
fluoroscopy, 6
flux density, 3
flux indicator, 4
flux penetration, 4
focal spot, 6
focused probe, 2
fog (dichroic, exposure, inherent), 6
frequency—see acoustic frequency, 2
fundamental frequency, 2, 2
furring, 4
gain, 2
gain control, 2
gamma radiation (or rays), 6
gamma radiography, 6
gamma ray source, 6
gap scanning, 2
gate, 2. 3
geometric unsharpness, 6
ghost echo, 2
gradient, 6
graininess, 6
grain size, 6
grass, 2
gray, 6
half-life, 6
half-value layer, 6
hard radiation, 6
hardener, 6
harmonic frequency, 2
horizontal linearity, 2
29
IACS, 3
image definition, 6
image intensifier, 6
image quality indicator (IQI), 6
immersion probe, 2
immersion testing, 2
impedance, 3
impedance analysis, 3
impedance diagram, 3
indication, 1, 2
indirect scan, 2
induced current flow method, 4
inherent filtration, 6
inherent fog, 6
initial pulse indication, 2
intensifying factor, 6
intensifying screen, 6
interface, 2
interface triggering (interface gating), 2
internal coil, 3
ionizing radiation, 6
IQI sensitivity, 6
Lamb wave, 2
latent image, 6
lift-off effect, 3
line focus, 6
linear accelerator (linac), 6
longitudinal magnetization, 4
magnetic circuit, 4
magnetic field, 3, 4
magnetic field distribution, 4
magnetic field leakage, 4
magnetic field strength, 3, 4
magnetic flow equipment, 4
magnetic flow method, 4
magnetic flux, 3, 4
magnetic flux density, 3, 4
magnetic ink, 4
magnetic leakage field, 4
magnetic particle testing, 1
magnetic particle testing equipment, 4
magnetic permeability (µ), 4
magnetic poles, 4
magnetic powder, 4
magnetic saturation, 4
magnetic saturation (a.c.), 3
magnetic saturation (d.c.), 3
magnetic writing, 4
magnetization, 4
marker, 2
masking, 6
metal intensifying screen (metal screen), 6
microradiography, 6
mode transformation, 2
modulation analysis, 3
monitor, 3, 2
movement unsharpness, 6
multiple echo, 2
near zone, 2
neutron radiography, 6
noise, 2, 3
non-destructive testing, 1
non-screen type film, 6
normal probe, 2
object-to-film distance, 6
optimum frequency, 3
overall system gain, 2
over development, 6
panoramic radiography, 6
paralysis, 3
particle content, 4
peak current, 4
penetrant, 5
penetrant removal, 5
penetrant station, 5
penetrant testing, 1
penetration time, 5
penumbra, 6
penetrometer—see under quality indicator, 6
phase analysis, 3
phase angle, 3
phase shift, 3
phase sensitive system, 3
phasing out, 3
phasor, 3
post-emulsifiable penetrant, 5
post-emulsifier, 5
potter bucky diaphragm, 6
pressure mark, 6
primary coil, 3
primary radiation, 6
probe, angle-, compression wave-, focused-,
immersion-, normal-, shear wave-, single-,
surface wave-, variable angle-), 2
probe coil, 3
probe index, 2
probe shoe, 2
prods, 4
profile pole pieces, 4
pulse, 2
pulse echo method, 2
pulse envelope, 2
pulse length (pulse duration), 2
pulse repetition frequency, 2
pulse spectrum, 2
Q factor, 3
quenching of fluorescence, 5
rad-see gray, 6
radiation (gamma-, hard-, ionizing-, primary-,
scattered-, secondary-, X-), 6
radiation testing, 1
radioactivity, 6
radiograph, 6
radiographic contrast, 6
radiographic film, 6
radiographic paper, 6
radiographic projection method, 6
radiography, 6
radioisotope (radionuclide), 6
radiology, 6
range of correct exposure, 6
Rayleigh wave—see surface wave, 2
reciprocity failure, 6
reciprocity law (Bunsen-Roscoe law), 6
recognition envelope, 2
recovery time, 3
rectification, 6
full wave-, half-wave-, 6
reference block, 2
reference level, 2
reference pieces, 5
reference sensitivity, 2
reverence standard (reference piece), 3
rem—see sievert, 6
replenisher, 6
residual magnetism, 4
residual magnetization method, 4
resolution, 3, 6
resolution (ultrasonic), 2
response time, 3
reticulation, 6
reversal, 6
rod-anode tube, 6
roentgen—see coulomb per kilogram (c/kg), 6
safelight, 6
salt screen, 6
secondary radiation, 6
scale expansion, 2
scanning, 2
scattered radiation, 6
scintillation, 6
scintillation counter, 6
AS 1929—1981
screen (intensifying-, fluorometallic-, metal
intensifying-, salt-), 6
screen-type film, 6
screen unsharpness, 6
sealed source, 6
search coil, 3
secondary coil, 3
secondary radiation, 6
sensitivity, 2, 6
sensitivity (acoustic), working-, reference-, 2,
sensitivity (radiation) (defect-, discontinuity-,
equivalent-, IQI-, spectral-), 6
sensitometric curve—see characteristic curve
6
settling time, 4
shear wave, 2
shear wave probe, 2
shielded coil, 3
sievert, 6
signal-to-noise ratio, 3
single probe, 2
skin effect, 3
skip distance, 2
‘soft’ radiation, 6
solvent removable penetrant, 5
source, 6
source shift radiography, 6
source size (effective), 6
source strength (gamma rays), 6
source-to-film distance (SFD), 6
specific activity, 6
spectral sensitivity, 6
specular reflection, 2
split coil, 4
spurious echo, 2
standard crack test panel, 5
step wedge, 6
stereo-radiography, 6
stop bath, 6
subject contrast, 6
suppression, 2, 3
surface coil, 3
surface field, 4
surface wave, 2
surface wave probe, 2
survey meter—see dose rate meter, 6
sustained magnetization method, 4
Sutherland flask, 4
target, 6
tenth value thickness, 6
test speed, 3
threading bar method, 4
threading coil method, 4
through transmission method, 2
time base, 2
tomography, 6
transducer, 2
transfer loss, 2
transmission point, 2
tube current, 6
tube diaphragm, 6
tube head, 6
tube shield, 6
tube window, 6
twin probe, 2
ultrasonic holography, 2
ultrasonic spectroscopy, 2
under-development, 6
unsharpness (film-, geometric-, movement-,
screen-), 6
useful density range, 6
Van der graaf generator, 6
variable angle probe, 2
velocity of propagation, 2
vertical linearity, 2
AS 1929—1981
water-washable penetrant method, 5
wave,
Raleigh, shear, surface, 2
wave-train, 2
wave-front, 2
wave-interference, 2
wavelength, 2
30
wedge, 2
wheel probe, 2
wobulation, 3
working sensitivity, 2
X-radiation (or X-rays), 6
X-ray film, 6
X-ray paper, 6
xero-radiography, 6
yoke, 4
zone (dead-, far-, near-), 2