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Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

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■ Example 1: Suppose a radiograph made on Film Z (See Figure 47) with<br />

an exposure <strong>of</strong> 12 mAmin has a density <strong>of</strong> 0.8 in the region <strong>of</strong> maximum<br />

interest. It is desired to increase the density to 2.0 for the sake <strong>of</strong> the<br />

increased contrast there available. Place the straightedge across Figure 54<br />

so that it cuts the Film Z scale at 0.8. The reading on the outside scales is<br />

then 9.8. Now move the straightedge upward so that it cuts the Film Z scale<br />

at 2.0; the reading on the outside scales is now 41. The original exposure (12<br />

mA-min) must be multiplied by the ratio <strong>of</strong> these two numbers--that is, by<br />

41/9.8 = 4.2. Therefore, the new exposure is 12 x 4.2 mA-min or 50 mA-min.<br />

Charlie Chong/ Fion Zhang<br />

<strong>Radiography</strong> in Modern Industry. Rochester, NY: Eastman <strong>Kodak</strong> Co. 1980

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