Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

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Estimating Exposures For Multithickness Specimens A minimum acceptable density for radiographs is often specified, not because of any virtue in the particular density, but because the slope of the characteristic curve (and hence the film contrast) below a certain point is too low for adequate rendition (rendering: expressing) of detail. Similarly, a maximum acceptable density is often designated because either the film contrast is lower at high densities or detail cannot be seen on the available illuminators if the density is above a certain value. The problem of radiographing a part having several thicknesses is one of using the available density range most efficiently. In other words, the kilovoltage and exposure should be adjusted so that the image of the thinnest part has the maximum acceptable density, and the thickest has the minimum. Exposure charts alone, although adequate for the radiography of uniform plates, can serve only as rough guides for articles having considerable variation in thickness. Charlie Chong/ Fion Zhang Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980
Previous experience is a guide, but even when a usable radiograph has been obtained, the question remains as to whether or not it is the best that could be achieved. A quantitative method for finding such exposures combines information derived from the exposure chart and the characteristic curve of the film used. The procedure is outlined below: Assume that 1.0 is the lowest acceptable density on Film X (See Figure 47) and that 3.5 is the highest. As shown in the figure below, this density interval corresponds to a certain log exposure interval, in this case 0.63. Charlie Chong/ Fion Zhang Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980
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Reading time for Radiography in Mod
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Kypoints: Kilovoltage changes/ Sour
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X-Ray Exposure Chart Charlie Chong/
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X-Ray Exposure Chart Charlie Chong/
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Radiation Dosage Calculator Charlie
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We can now solve for any unknown by
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■ Example: Suppose that with a gi
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■ Tabular Solution of Milliampera
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Table V: Milliamperage-Time and Dis
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■ Milliamperage-Time Relation Rul
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Departures may be apparent, however
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Table VI: Approximate Corrections f
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Charlie Chong/ Fion Zhang Radiograp
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The characteristic of the logarithm
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The preceding table illustrates a v
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Transmittance T = I t /I o Opacity
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X-Ray Exposure Charts An exposure c
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Preparing An Exposure Chart A simpl
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Exposure Chart thickness is on a li
Page 39 and 40: Any given exposure chart applies to
Page 41 and 42: 3. The use of a different type of f
Page 43 and 44: 4. A change in processing condition
Page 45 and 46: Figure 45: Typical exposure chart f
Page 47 and 48: Figure 46: Typical gamma-ray exposu
Page 49 and 50: Figure 47: Characteristic curves of
Page 51 and 52: The use of the logarithm of the rel
Page 53 and 54: As Figure 47 shows, the slope (or s
Page 55 and 56: ■ Example 1: Suppose a radiograph
Page 57 and 58: Figure 48: Circled numerals in the
Page 59 and 60: Figure 49: Characteristic curves of
Page 61 and 62: Graphical Solutions To Sensitometri
Page 63 and 64: Figure 54: Typical nomogram for sol
Page 67 and 68: ■ Example 2: Film X has a higher
Page 69 and 70: ■ Example 3: The types of problem
Page 71 and 72: Figure 54: Typical nomogram for sol
Page 75 and 76: ■ Example 3: The types of problem
Page 77 and 78: Only if the conditions used in prac
Page 79 and 80: Figure 55: Pattern of transparent o
Page 81 and 82: 2. Source-film distance. Since the
Page 83 and 84: Figure 57: Overlay positioned so as
Page 85 and 86: Figure 58: Overlay positioned so as
Page 87 and 88: 5. Film density. Exposure charts ap
Page 89: Figure 59: Overlay positioned so as
Page 93 and 94: The antilog of 0.63 is 4.3, which m
Page 95 and 96: Figure 61: Abridged form of the exp
Page 97 and 98: Figure 62: System of lines drawn on
Page 99 and 100: Use Of Multiple Films If the chart
Page 101 and 102: Although the lines of an exposure c
Page 103 and 104: Chapter 8: Radiographic Image Quali
Page 105 and 106: Charlie Chong/ Fion Zhang https://w
Page 107 and 108: Figure 63: Advantage of higher radi
Page 109 and 110: Figure 64: With the same specimen,
Page 111 and 112: Figure 64: With the same specimen,
Page 113 and 114: These data are from the exposure ch
Page 115 and 116: Film Graininess, Screen Mottle (See
Page 117 and 118: Penetrameters A standard test piece
Page 119 and 120: Figure 65: American Society for Tes
Page 121 and 122: ASTM penetrameter (ASTM E 1026). Ch
Page 123 and 124: Penetrameter (IQI). Charlie Chong/
Page 125 and 126: IQI Penetrameter (IQI). Charlie Cho
Page 127 and 128: The first symbol (2) indicates that
Page 129 and 130: ■ Equivalent Penetrameter Sensiti
Page 131 and 132: In practically all cases, the penet
Page 133 and 134: ■ Wire Penetrameters A number of
Page 135 and 136: ■ Comparison of Penetrameter Desi
Page 137 and 138: ■ Penetrameters and Visibility of
Page 139 and 140: Viewing & Interpreting Radiographs
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Charlie Chong/ Fion Zhang http://ww
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Charlie Chong/ Fion Zhang
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Figure 67: The silver bromide grain
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Figure 69: Cross section showing th
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Selection Of Films For Industrial R
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Figure 70 indicates the direction t
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Film Packaging Industrial x-ray fil
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■ Envelope Packing with Integral
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Handling Of Film X-ray film should
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At high voltage, direct exposure te
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Shipping Of Unprocessed Films If un
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The storage period should not excee
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Table VII: Cobalt 60 Storage Condit
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These show the necessary emitter-fi
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Assume that a radiographic source i
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First, if several sources, say four
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Storage Of Exposed And Processed Fi
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Commercial Keeping Since definite r
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1 A term commonly used to describe
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Manual Film Processing ■ https://
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Chapter 10: Fundamentals of Process
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General Considerations ■ Cleanlin
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Paddles or plunger-type agitators a
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Figure 71: Method of fastening film
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■ Cleanliness Processing tanks sh
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Within certain limits, these change
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♦ Control of Temperature and Time
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Film Processing Parameters Develope
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Figure 72: An example of streaking
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Agitation of the film during develo
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Immediately after the hangers are l
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Figure 73: Distribution manifold fo
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♦ Activity of Developer Solutions
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The exact quantity of replenisher c
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■ Stop Bath A stop bath consistin
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When development is complete, the f
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Fixing The purpose of fixing is to
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During use, the fixer solution accu
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Figure 74: Water should flow over t
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Figure 75: Schematic diagram of a c
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Formation of a cloud of minute bubb
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Drying Convenient racks are availab
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Other characteristic marks are dark
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Figure 76: An automated processor h
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X-Ray Automatic Processing Charlie
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Automated Processor Systems Automat
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In most automated processors now in
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Water System The water system of au
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Replenishment Systems Accurate repl
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Dryer System Rapid drying of the pr
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Uniformity of Radiographs Automated
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Chemistry of Automated Processing A
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This control is accomplished by har
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Film-Feeding Procedures Sheet Film
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Roll Film Roll films in widths of 1
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Filing Radiographs After the radiog
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Chapter 11: Process Control Users o
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Equipment & Materials Most of the e
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Refrigerator After exposure, contro
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General Aspects The information tha
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■ Identify each strip. Place half
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Process Control Charts Two steps on
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Control limits for variables of the
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Figure 79: Densitometric data for p
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Process Control Technique Certain m
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When the processed control strips i
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■ Processing of Control Strips Pr
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Discussion Densitometric data and p
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Figure 81: Control chart for one ex
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Reading time for Radiography in Mod
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Processing Area The volume of films
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Figure 82: Plan of a manual x-ray p
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■ Loading Bench Basically, operat
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■ Film Dryers One of the importan
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Figure 83: A schematic diagram of a
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General Considerations There are a
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Wall Covering The walls of the proc
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Illumination The processing area mu
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Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

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