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Radiographic Testing Instructor Guide l LESSON 1
Discovery and History of Radioactive Materials
1. X-rays were discovered accidentally in 1895 by Wilhelm Conrad Röntgen. He noticed that a screen
painted with barium platinocyanide fluoresced when placed in close proximity to an electrical discharge
tube. He called the resulting rays X-rays because their nature was unknown.
2. In 1898, Marie Curie studied uranium and thorium, and called their spontaneous decay process
“radioactivity.” With her husband Pierre, she also discovered the radioactive elements polonium and
radium.
3. In 1912, German physicist Max von Laue and other investigators identified X-rays as electromagnetic
waves similar in nature to visible light however, X-rays are invisible and they have far greater penetrating
ability than light.
Industrial Radiography
1. The first industrial radiological department was formed at Woolwich Arsenal in England in 1930 the
U.S. Navy agreed to accept fusion-welded boiler drums, if the welds were tested by X-rays.
2. The American Society of Mechanical Engineers (ASME), ASTM International (formerly, the American
Society for Testing and Materials), and inspection agencies such as Lloyds Register of Shipping and
Admiralty incorporated industrial radiographic approval into their inspection codes for fusion-welded
Class I boilers and pressure vessels.
3. During World War II, with the increased production of aircraft and ships, radiographic testing was in
great demand as a nondestructive testing (NDT) method. More recently, radiographic testing has been
used to inspect critical welds in all aspects of atomic research and nuclear energy programs.
Test Objective
1. The objective of radiographic testing is to ensure product reliability.
2. As an NDT method, radiographic testing enables the technician to view the internal quality of the test
object or show the internal configuration of the components without impairing the usefulness of the
material.
3. Performing the actual radiographic test is only part of the procedure. The results of the test must be
interpreted to acceptance standards, after which the test objects are accepted or rejected.
Test Setup
1. Figure 1 shows the essential features in the exposure of a radiograph. The radiation proceeds in straight
lines to the object some of the rays pass through and others are absorbed, with the amount transmitted
depending on the nature (for example, density) of the material and its thickness.
Radiographic Testing Instructor Guide l LESSON 1
Discovery and History of Radioactive Materials
1. X-rays were discovered accidentally in 1895 by Wilhelm Conrad Röntgen. He noticed that a screen
painted with barium platinocyanide fluoresced when placed in close proximity to an electrical discharge
tube. He called the resulting rays X-rays because their nature was unknown.
2. In 1898, Marie Curie studied uranium and thorium, and called their spontaneous decay process
“radioactivity.” With her husband Pierre, she also discovered the radioactive elements polonium and
radium.
3. In 1912, German physicist Max von Laue and other investigators identified X-rays as electromagnetic
waves similar in nature to visible light however, X-rays are invisible and they have far greater penetrating
ability than light.
Industrial Radiography
1. The first industrial radiological department was formed at Woolwich Arsenal in England in 1930 the
U.S. Navy agreed to accept fusion-welded boiler drums, if the welds were tested by X-rays.
2. The American Society of Mechanical Engineers (ASME), ASTM International (formerly, the American
Society for Testing and Materials), and inspection agencies such as Lloyds Register of Shipping and
Admiralty incorporated industrial radiographic approval into their inspection codes for fusion-welded
Class I boilers and pressure vessels.
3. During World War II, with the increased production of aircraft and ships, radiographic testing was in
great demand as a nondestructive testing (NDT) method. More recently, radiographic testing has been
used to inspect critical welds in all aspects of atomic research and nuclear energy programs.
Test Objective
1. The objective of radiographic testing is to ensure product reliability.
2. As an NDT method, radiographic testing enables the technician to view the internal quality of the test
object or show the internal configuration of the components without impairing the usefulness of the
material.
3. Performing the actual radiographic test is only part of the procedure. The results of the test must be
interpreted to acceptance standards, after which the test objects are accepted or rejected.
Test Setup
1. Figure 1 shows the essential features in the exposure of a radiograph. The radiation proceeds in straight
lines to the object some of the rays pass through and others are absorbed, with the amount transmitted
depending on the nature (for example, density) of the material and its thickness.