Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

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The Reciprocity Law In the sections immediately preceding, it has been assumed that exact compensation for a decrease in the time of exposure can be made by increasing the milliamperage according to the relation M 1 T 1 = M 2 T 2 . This may be written MT = C or (E) and is an example of the general photochemical law that the same effect is produced for IT = constant, where I is intensity of the radiation and T is the time of exposure. It is called the reciprocity law and is true for direct x-ray and lead screen exposures. For exposures to light, it is not quite accurate and, since some radiographic exposures are made with the light from fluorescent intensifying screens, the law cannot be strictly applied. Errors as the result of assuming the validity of the reciprocity law are usually so small that they are not noticeable in examples of the types given in the preceding sections. Charlie Chong/ Fion Zhang Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980
Departures may be apparent, however, if the intensity is changed by a factor of 4 or more. Since intensity may be changed by changing the source-film distance, failure of the reciprocity law may appear to be a violation of the inverse square law. Applications of the reciprocity law over a wide intensity range sometimes arise, and the relation between results and calculations may be misleading unless the possibility of failure of the reciprocity law is kept in mind. Failure of the reciprocity law means that the efficiency of a lightsensitive emulsion in utilizing the light energy depends on the light intensity. Reciprocity Failure Under the usual conditions of industrial radiography, the number of milliampere-minutes required for a properly exposed radiograph made with fluorescent intensifying screens increases as the x-ray intensity decreases, because of reciprocity failure. Comments: In this case the reciprocity failure failure is due to no linearity of MT relation. Charlie Chong/ Fion Zhang Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980
Page 1 and 2: Reading time for Radiography in Mod
Page 3 and 4: Kypoints: Kilovoltage changes/ Sour
Page 5 and 6: X-Ray Exposure Chart Charlie Chong/
Page 7 and 8: X-Ray Exposure Chart Charlie Chong/
Page 9 and 10: Radiation Dosage Calculator Charlie
Page 11 and 12: We can now solve for any unknown by
Page 13 and 14: ■ Example: Suppose that with a gi
Page 15 and 16: ■ Tabular Solution of Milliampera
Page 17 and 18: Table V: Milliamperage-Time and Dis
Page 19: ■ Milliamperage-Time Relation Rul
Page 23 and 24: Table VI: Approximate Corrections f
Page 25 and 26: Charlie Chong/ Fion Zhang Radiograp
Page 27 and 28: The characteristic of the logarithm
Page 29 and 30: The preceding table illustrates a v
Page 31 and 32: Transmittance T = I t /I o Opacity
Page 33 and 34: X-Ray Exposure Charts An exposure c
Page 35 and 36: Preparing An Exposure Chart A simpl
Page 37 and 38: 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 65 and 66: ■ Example 1: Suppose a radiograph
Page 67 and 68: ■ Example 2: Film X has a higher
Page 69 and 70: ■ Example 3: The types of problem
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Figure 54: Typical nomogram for sol
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■ Example 1: Suppose a radiograph
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■ Example 3: The types of problem
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Only if the conditions used in prac
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Figure 55: Pattern of transparent o
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2. Source-film distance. Since the
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Figure 57: Overlay positioned so as
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5. Film density. Exposure charts ap
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Previous experience is a guide, but
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The antilog of 0.63 is 4.3, which m
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Figure 61: Abridged form of the exp
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Figure 62: System of lines drawn on
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Use Of Multiple Films If the chart
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Although the lines of an exposure c
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Chapter 8: Radiographic Image Quali
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Charlie Chong/ Fion Zhang https://w
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Figure 63: Advantage of higher radi
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Figure 64: With the same specimen,
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Figure 64: With the same specimen,
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These data are from the exposure ch
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Film Graininess, Screen Mottle (See
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Penetrameters A standard test piece
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Figure 65: American Society for Tes
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ASTM penetrameter (ASTM E 1026). Ch
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Penetrameter (IQI). Charlie Chong/
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IQI Penetrameter (IQI). Charlie Cho
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The first symbol (2) indicates that
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■ Equivalent Penetrameter Sensiti
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In practically all cases, the penet
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■ Wire Penetrameters A number of
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■ Comparison of Penetrameter Desi
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■ Penetrameters and Visibility of
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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
Page 295 and 296:
Illumination The processing area mu
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Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

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