Radiography in Modern Industry - Kodak

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Figure 7: Top: Rod-anode tube used in the examination of a plug weld. Bottom: Rodanodetube with a 360° beam used to examine a circumferential weld in a single exposure.Flash X-Ray MachinesFlash x-ray machines are designed to give extremely short (microsecond), extremely intensebursts of x-radiation. They are intended for the radiography of objects in rapid motion or the studyof transient events (See "High Speed Radiography"). The high-voltage generators of these unitsgive a very short pulse of high voltage, commonly obtained by discharging a condenser acrossthe primary of the high-voltage transformer. The x-ray tubes themselves usually do not have afilament. Rather, the cathode is so designed that a high electrical field "pulls" electrons from themetal of the cathode by a process known as field emission, or cold emission. Momentary electroncurrents of hundreds or even thousands of amperes--far beyond the capacity of a heatedfilament--can be obtained by this process.High-Voltage EquipmentThe betatron may be considered as a high-voltage transformer, in which the secondary consistsof electrons circulating in a doughnut-shaped vacuum tube placed between the poles of analternating current electromagnet that forms the primary. The circulating electrons, accelerated tohigh speed by the changing magnetic field of the primary, are caused to impinge on a targetwithin the accelerating tube.In the linear accelerator, the electrons are accelerated to high velocities by means of a highfrequencyelectrical wave that travels along the tube through which the electrons travel.Both the betatron and the linear accelerator are used for the generation of x-radiation in themultimillion-volt range.Radiography in Modern Industry 14
Table I - Typical X-ray Machines and Their ApplicationsMaximumvoltage (kV)ScreensApplications and Approximate Thickness Limits50 None Thin sections of most metals; moderate thickness of graphite andberyllium; small electronic components; wood, plastics, etc.1503004001000None or leadfoilFluorescentLead foilFluorescentLead foilFluorescentLead foilFluorescent5-inch aluminum or equivalent. (See Table IV)1-inch steel or equivalent.1 1 / 2 -inch steel or equivalent. (See Table IV)3-inch steel or equivalent.4-inch steel or equivalent.3 1 / 2 -inch steel or equivalent.4 1 / 2 -inch steel or equivalent.5-inch steel or equivalent.8-inch steel or equivalent.2000 Lead foil 8-inch steel or equivalent.8 to 25 MeVLead foilFluorescent16-inch steel or equivalent.20-inch steel or equivalent.In the high-voltage electrostatic generator, the high voltage is supplied by static negative chargesmechanically conveyed to an insulating electrode by a moving belt. Electrostatic generators areused for machines in the 1- and 2-million-volt range.No attempt is made here to discuss in detail the various forms of electrical generating equipment.The essential fact is that electrons must be accelerated to very great velocities in order that theirdeceleration, when they strike the target, may produce x-radiation.In developing suitable exposure techniques, it is important to know the voltage applied to the x-ray tube. It is common practice for manufacturers of x-ray equipment to calibrate their machinesat the factory. Thus, the operator may know the voltage across the x-ray tube from the readingsof the volt-meter connected to the primary winding of the high-voltage transformer.Application of Various Types of X-Ray ApparatusThe various x-ray machines commercially available may be roughly classified according to theirmaximum voltage. The choice among the various classes will depend on the type of work to bedone. Table I lists voltage ranges and applications of typical x-ray machines. The voltage rangesare approximate since the exact voltage limits of machines vary from one manufacturer toanother. It should be emphasized that a table like the one table I can serve only as the roughestsort of guide, since x-ray machines differ in their specifications, and radiographic tasks differ intheir requirements.X-ray machines may be either fixed or mobile, depending on the specific uses for which they areintended. When the material to be radiographed is portable, the x-ray machine is usuallypermanently located in a room protected against the escape of x-radiation. The x-ray tube itself isfrequently mounted on a stand allowing considerable freedom of movement. For the examinationRadiography in Modern Industry 15
Page 1 and 2: RadiographyinModernIndustry
Page 3 and 4: RadiographyinModernIndustryFOURTH E
Page 5 and 6: ContentsIntroduction...............
Page 7 and 8: Chapter 1: The Radiographic Process
Page 9 and 10: Intensifying ScreensX-ray and other
Page 11 and 12: makes it a very suitable material f
Page 13: Figure 6: Typical voltage waveforms
Page 17 and 18: The wavelengths (or energies of rad
Page 19 and 20: Table III - Industrial Gamma-Ray So
Page 21 and 22: 1. The source of light should be sm
Page 23 and 24: B and H in the Figure 13 show the e
Page 25 and 26: Figure 14: Geometric construction f
Page 27 and 28: Figure 17: Pinhole pictures of the
Page 29 and 30: The kilovoltage applied to the x-ra
Page 31 and 32: Figure 21: Schematic diagram of som
Page 33 and 34: kind of material radiographed, the
Page 35 and 36: instance, the kilovoltage may be fi
Page 37 and 38: The technique need not be limited t
Page 39 and 40: Chapter 5: Radiographic ScreensWhen
Page 41 and 42: Contact between the film and the le
Page 43 and 44: Figure 29: The number of electrons
Page 45 and 46: lead foil screens ran be retained w
Page 47 and 48: Figure 33: The sharpness of the rad
Page 49 and 50: Figure 34: Low density (right) is a
Page 51 and 52: such as a wall or floor, on the fil
Page 53 and 54: from this source. Since scatter als
Page 55 and 56: A filter reduces excessive subject
Page 57 and 58: Definite rules as to filter thickne
Page 59 and 60: 0.010-inch front screen of value be
Page 61 and 62: Example: Suppose that with a given
Page 63 and 64: If the milliamperage remains consta
Page 65 and 66:
espectively. In other words, a cons
Page 67 and 68:
Any given exposure chart applies to
Page 69 and 70:
Figure 46: Typical gamma-ray exposu
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where the slope of the characterist
Page 73 and 74:
Figure 49: Characteristic curves of
Page 75 and 76:
Figure 51: Characteristic curve of
Page 77 and 78:
Nomogram MethodsIn Figure 54, the s
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Figure 56: Transparent overlay posi
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Figure 58: Overlay positioned so as
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The problem of radiographing a part
Page 85 and 86:
Figure 62: System of lines drawn on
Page 87 and 88:
Chapter 8: Radiographic Image Quali
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Film contrast refers to the slope (
Page 91 and 92:
Hole Type PenetrametersThe common p
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of the same thickness as the specim
Page 95 and 96:
Chapter 9: Industrial X-ray FilmsMo
Page 97 and 98:
Figure 70 indicates the direction t
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the lead letters on a radiation-abs
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Therefore, protection requirements
Page 103 and 104:
5. Avoid pressure damage caused by
Page 105 and 106:
Paddles or plunger-type agitators a
Page 107 and 108:
slow, and the development time reco
Page 109 and 110:
ubbles make their way to the surfac
Page 111 and 112:
When development is complete, the f
Page 113 and 114:
soften considerably with prolonged
Page 115 and 116:
Figure 77: The roller transport sys
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Rapid Access to Processed Radiograp
Page 119 and 120:
Figure 78: Film-feeding procedures
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Chapter 11: Process ControlUsers of
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3. Age of the developer replenisher
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Figure 80: Control chart below for
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DiscussionDensitometric data and pr
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Figure 82: Plan of a manual x-ray p
Page 131 and 132:
Figure 83: A schematic diagram of a
Page 133 and 134:
loading-bench activities are carrie
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KODAK Quinone-Thiosulfate Intensifi
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Methylene-Blue MethodTwo variations
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KODAK Hypo Test Solution HT-2Avoird
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In summary, use of the test papers
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narrow angle would be very thick, e
Page 145 and 146:
When radiation passes through a spe
Page 147 and 148:
Figure 89: Demonstration of the eff
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Figure 90: The amount of gamma radi
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The radiograph exposed in the right
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To illustrate, let us assume that t
Page 155 and 156:
Figure 95: High-speed x-ray picture
Page 157 and 158:
Figure 97: Two methods of neutron r
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Duplicating RadiographsSimultaneous
Page 161 and 162:
Sometimes, as when sets of referenc
Page 163 and 164:
PhotofluorographyIn photofluorograp
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discontinuities or of segregation i
Page 167 and 168:
from the camera or by reaching down
Page 169 and 170:
Figure 106: Schematic diagram of th
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valuable technique, for instance, i
Page 173 and 174:
The position of the spots is determ
Page 175 and 176:
Powder Diffraction File, Internatio
Page 177 and 178:
Processing TechniquesRadiographs on
Page 179 and 180:
Since this formula applies only to
Page 181 and 182:
such that it does not distort the i
Page 183 and 184:
Figure 113: A: Representation of a
Page 185 and 186:
Figure 115: Characteristic curve of
Page 187 and 188:
film fairly well. If high densities
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Density = 1.5 Density = 2.5Film Rel
Page 191 and 192:
In most industrial radiography, the
Page 193 and 194:
e noted here. Although the average
Page 195 and 196:
Chapter 17: Film Graininess; Signal
Page 197 and 198:
The ratio of signal to noise has a
Page 199 and 200:
Chapter 18: The Photographic Latent
Page 201 and 202:
Thus, the change that makes an expo
Page 203 and 204:
Figure 130: Stages in the developme
Page 205 and 206:
electrons by successive Compton int
Page 207 and 208:
Development is essentially a chemic
Page 209 and 210:
Chapter 19: ProtectionOne of the mo
Page 211 and 212:
duct is brought into the x-ray room
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Radiography in Modern Industry - Kodak

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