Radiography in Modern Industry - Kodak

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development at too high a temperature; or storing films under improper storage conditions (see"Storage Of Exposed And Processed Film") or beyond the expiration dates stamped on thecartons.Accidental exposure of the film to x-radiation or gamma radiation is a common occurrencebecause of insufficient protection from high-voltage tubes or stored radioisotopes; films havebeen fogged through 1/8 inch of lead in rooms 50 feet or more away from an x-ray machine.Automated Film ProcessingAutomated processing requires a processor (See Figure 76), specially formulated chemicals andcompatible film, all three of which must work together to produce high-quality radiographs. Thissection describes how these three components work together.Figure 76: An automated processor has three main sections: a film-feeding section; afilm-processing section (developer, fixer, and wash); and a film-drying section.Processing ControlThe essence of automated processing is control, both chemical and mechanical. In order todevelop, fix, wash, and dry a radiograph in the short time available in an automated processor,specifically formulated chemicals are used. The processor maintains the chemical solutions at theproper temperatures, agitates and replenishes the solutions automatically, and transports thefilms mechanically at a carefully controlled speed throughout the processing cycle. Filmcharacteristics must be compatible with processing conditions, shortened processing times andthe mechanical transport system. From the time a film is fed into the processor until the dryradiograph is delivered, chemicals, mechanics, and film must work together.Automated Processor SystemsAutomated processors incorporate a number of systems which transport, process, and dry thefilm and replenish and recirculate the processing solutions. A knowledge of these systems andhow they work together will help in understanding and using automated processing equipment.Transport SystemThe function of the transport system (See Figure 77) is to move film through the developer andfixer solutions and through the washing and drying sections, holding the film in each stage of theprocessing cycle for exactly the right length of time, and finally to deliver the ready-to-readradiograph.Radiography in Modern Industry 114
Figure 77: The roller transport system is the backbone of an automated processor. Thearrangement and number of its components vary, but the basic plan is virtually the same.In most automated processors now in use, the film is transported by a system of rollers driven bya constant speed motor. The rollers are arranged in a number of assemblies--entrance rollerassembly, racks, turnarounds (which reverse direction of film travel within a tank), crossovers(which transfer films from one tank to another), and a squeegee assembly (which removessurface water after the washing cycle). The number and specific design of the assemblies mayvary from one model of processor to another, but the basic design is the same.It is important to realize that the film travels at a constant speed in a processor, but that the speedin one model may differ from that in another. Processing cycles--the time interval from theinsertion of an unprocessed film to the delivery of a dry radiograph--in general range downwardfrom 15 minutes. Because one stage of the cycle may have to be longer than another, the racksmay vary in size--the longer the assembly, the longer the film takes to pass through a particularstage of processing.Although the primary function of the transport system is to move the film through the processor ina precisely controlled time, the system performs two other functions of importance to the rapidproduction of high-quality radiographs. First, the rollers produce vigorous uniform agitation of thesolutions at the surfaces of the film, contributing significantly to the uniformity of processing.Second, the top wet rollers in the racks and the rollers in the crossover assemblies effectivelyremove the solutions from the surfaces of the film, reducing the amount of solution carried overfrom one tank to the next and thus prolonging the life of the fixer and increasing the efficiency ofwashing. Most of the wash water clinging to the surface of the film is removed by the squeegeerollers, making it possible to dry the processed film uniformly and rapidly, without blemishes.Water SystemThe water system of automated processors has two functions - to wash the films and to helpstabilize the temperature of the processing solutions. Hot and cold water are blended to theproper temperature and the tempered water then passes through a flow regulator which providesa constant rate of flow. Depending upon the processor, part or all of the water is used to helpcontrol the temperature of the developer. In some processors, the water also helps to regulate thetemperature of the fixer. The water then passes to the wash tank where it flows through and overthe wash rack. It then flows over a weir (dam) at the top of the tank and into the drain.Radiography in Modern Industry 115
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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
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B and H in the Figure 13 show the e
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Figure 14: Geometric construction f
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Figure 17: Pinhole pictures of the
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The kilovoltage applied to the x-ra
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Figure 21: Schematic diagram of som
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kind of material radiographed, the
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instance, the kilovoltage may be fi
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The technique need not be limited t
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Chapter 5: Radiographic ScreensWhen
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Contact between the film and the le
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Figure 29: The number of electrons
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lead foil screens ran be retained w
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Figure 33: The sharpness of the rad
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Figure 34: Low density (right) is a
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such as a wall or floor, on the fil
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from this source. Since scatter als
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A filter reduces excessive subject
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Definite rules as to filter thickne
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0.010-inch front screen of value be
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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 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
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: soften considerably with prolonged
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
Page 125 and 126: Figure 80: Control chart below for
Page 127 and 128: DiscussionDensitometric data and pr
Page 129 and 130: 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
Page 135 and 136: KODAK Quinone-Thiosulfate Intensifi
Page 137 and 138: Methylene-Blue MethodTwo variations
Page 139 and 140: KODAK Hypo Test Solution HT-2Avoird
Page 141 and 142: In summary, use of the test papers
Page 143 and 144: 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
Page 149 and 150: Figure 90: The amount of gamma radi
Page 151 and 152: The radiograph exposed in the right
Page 153 and 154: 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
Page 159 and 160: 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
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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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