Radiography in Modern Industry - Kodak

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usually requires somewhat more arithmetic but no equipment other than a diagram similar toFigure 54 and a ruler or straightedge.Graphical solutions of either type are often sufficiently accurate for the purposes of practicalindustrial radiography.Overlay MethodsAn example of a transparent overlay is shown in the Figure 50. The numbers on the horizontalline are exposure values. They can be taken, for example to be milliampere-minutes, milliampereseconds,curie-minutes, curie-hours, or an exposure factor. Further, all numbers on the line canbe multiplied by the same value, without affecting the use of the device. For instance, multiplyingby 10 makes the scale go from 10 to 10,000 (rather than from 1 to 1,000) of whatever exposureunit is convenient. Note that the overlay must be made to fit the characteristic curves with which itis to be used, since it is essential for the horizontal scales of both characteristic curves andoverlay to agree.The use of the overlay will be demonstrated by solving again some of the same problems used asillustrations in the foregoing section. Note that the vertical lines on the overlay must be parallel tothe vertical lines on the graph paper of the characteristic curve, and the horizontal line must beparallel to the horizontal lines on the graph paper.Example 1: Suppose a radiograph made on Film Z with an exposure of 12 mA-min has a densityof 0.8 in the region of maximum interest. It is desired to increase the density to 2.0 for the sake ofthe increased contrast there available.Locate the intersection of the line for the original density of 0.8 with the characteristic curve ofFilm Z (Point A in Figure 51). Superimpose the transparent overlay on the curve, so that thevertical line for the original exposure--12 mA-min--passes through point A and the horizontal lineoverlies the line for the desired final density of 2.0. The new exposure, 50 mA-min, is read at theintersection of the characteristic curve with the horizontal line of the overlay (Point B in Figure51).The method of solution would be the same if the new density were lower rather than higher thanthe old. The vertical line corresponding to the old exposure would pass through the characteristiccurve at the point of the old density. The horizontal line of the overlay would pass through thedesired new density. The new exposure would be read at the intersection of the characteristiccurve and the horizontal line of the overlay.Radiography in Modern Industry 74
Figure 51: Characteristic curve of Film Z. Transparent overlay of the figure abovepositioned for the graphical solution of Example 1.Example 2: Film X has a higher contrast at D = 2.0 than Film Z and also has a finer grain.Suppose that, for these reasons, it is desired to make the aforementioned radiograph on Film Xwith a density of 2.0 in the same region of maximum interest.Superimpose the overlay on the characteristic curve so that the horizontal line coincides with thehorizontal line for a density of 2.0, and position the overlay from left to right so that the curve forFilm Z cuts the line at the original exposure of 50 mA-min (Point C in Figure 52). Read the newexposure of 97.5 mA-min at the point at which the curve for Film X cuts the horizontal line (PointD in Figure 52).Figure 52: Characteristic curves of Films X and Z. Transparent overlay positioned for thegraphical solution of Example 2.Radiography in Modern Industry 75
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RadiographyinModernIndustry
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RadiographyinModernIndustryFOURTH E
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ContentsIntroduction...............
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Chapter 1: The Radiographic Process
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Intensifying ScreensX-ray and other
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makes it a very suitable material f
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Figure 6: Typical voltage waveforms
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Table I - Typical X-ray Machines an
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The wavelengths (or energies of rad
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Table III - Industrial Gamma-Ray So
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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
Page 71 and 72: where the slope of the characterist
Page 73: Figure 49: Characteristic curves of
Page 77 and 78: Nomogram MethodsIn Figure 54, the s
Page 79 and 80: Figure 56: Transparent overlay posi
Page 81 and 82: Figure 58: Overlay positioned so as
Page 83 and 84: 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
Page 89 and 90: Film contrast refers to the slope (
Page 91 and 92: Hole Type PenetrametersThe common p
Page 93 and 94: 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
Page 99 and 100: the lead letters on a radiation-abs
Page 101 and 102: 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
Page 117 and 118: Rapid Access to Processed Radiograp
Page 119 and 120: Figure 78: Film-feeding procedures
Page 121 and 122: Chapter 11: Process ControlUsers of
Page 123 and 124: 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
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Figure 83: A schematic diagram of a
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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
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When radiation passes through a spe
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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
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Figure 95: High-speed x-ray picture
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Figure 97: Two methods of neutron r
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Duplicating RadiographsSimultaneous
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Sometimes, as when sets of referenc
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PhotofluorographyIn photofluorograp
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discontinuities or of segregation i
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from the camera or by reaching down
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Figure 106: Schematic diagram of th
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valuable technique, for instance, i
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The position of the spots is determ
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Powder Diffraction File, Internatio
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Processing TechniquesRadiographs on
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Since this formula applies only to
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such that it does not distort the i
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Figure 113: A: Representation of a
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Figure 115: Characteristic curve of
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film fairly well. If high densities
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Density = 1.5 Density = 2.5Film Rel
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In most industrial radiography, the
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e noted here. Although the average
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Chapter 17: Film Graininess; Signal
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The ratio of signal to noise has a
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Chapter 18: The Photographic Latent
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Thus, the change that makes an expo
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Figure 130: Stages in the developme
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electrons by successive Compton int
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Development is essentially a chemic
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Chapter 19: ProtectionOne of the mo
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duct is brought into the x-ray room
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Radiography in Modern Industry - Kodak

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