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The History of X-ray

In this blog post, you’ll read:In today’s world, manufacturers order X-rays to detect the defects such as cracks, porosity, slag inclusion, incomplete fusion/penetration, mismatch, and much, much more. Digital radiography, the standard inspection method for flaw detection, uses X-rays. So, are you planning to use an X-ray to inspect your products before manufacturing? Smart choice!

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So, are you planning to use an X-ray to inspect your products before manufacturing? Smart choice! In this article, I am going to explain the history of industrial X-rays. Before we get started, let us hear the historical story of the invention of X-rays.


In today’s world, manufacturers order X-rays to detect the defects such as cracks, porosity, slag inclusion, incomplete fusion/penetration, mismatch, and much, much more. Digital radiography, the standard inspection method for flaw detection, uses X-rays. We barely think about the evolution of these X-rays, since it’s so omnipresent. But not so long ago, one could not visually detect any internal weld flaw without cutting the sample weld open.


The story behind the X-ray discovery

Thanks to Wilhelm Conrad Roentgen (1845-1923), Professor of Physics in Wurzburg, Bavaria, who discovered X-rays on November 8, 1895. Of course, it was an accidental discovery when he was checking if cathode rays from a Crookes tube could penetrate glass. The cathode tube was actually wrapped in heavy black colored paper. However, when a faint incandescent green light fled and displayed onto an adjacent fluorescent screen coated with barium platinocyanide about one meter away, he was totally surprised.


history of X-ray


By continuous research, he observed that the mysterious unexplained light could penetrate most of the objects although it leaves shadows of solid bodies. As he was unaware of the type or origin of these rays, he termed them ‘X,’ which means ‘unknown,’ rays.

X-rays are electromagnetic energy waves similar to light rays. However, their wavelengths are approximately 1,000 times lesser than the ultraviolet rays and light rays. However, their wavelength is longer than the gamma rays. X-rays have a wavelength that ranges from 10 picometers to 10 nanometers in accordance with energies (124 eV to 124 keV) and frequency range (30 petahertz to 30 exahertz).

Roentgen performed several experiments for seven weeks to improve his scientific data. Finally, on December 28, Roentgen submitted his initial “provisional” communication, “On a New Kind of Rays,” in the Proceedings of the Würzburg Physico-Medical Society. 


In January 1896, Roentgen presented the findings publicly with a demonstration before the same society where these rays were named “Roentgen’s Rays.”

One of the first photographic plates that he used for his experiments was a film of his wife Bertha’s hand, with a wedding ring visible clearly. 

Roentgen then found that X-rays can even penetrate human flesh as well so that it is possible to photograph the bones and tissue. However, it cannot pass through higher-density substances like bone or lead. The news of this X-ray discovery spread across the world. 


The medical community immediately recognized the significance of Roentgen’s discovery. By February 1896, the first use of X-rays was reported in the US in Dartmouth, MA, where Edwin Brant Frost developed a radiographic plate of a patient’s Colles fracture for his own brother, who is a doctor. Similarly, the first angiography, as well as military radiology, was performed in the year 1896. Hence in 1897, X-rays were used to detect bullets and broken bones inside the patient’s body during the Balkan War.

Within a year, doctors in the US and Europe started using X-rays to detect fractures, swallowed things, and gunshots. Not only for diagnostic purposes, but some researchers also started using X-rays for disease treatment as well. In January 1896, Emil Grubbe, a Chicago electrotherapist, irradiated a female with recurrent breast cancer. Looking at that, many researchers noticed its palliative effects on cancer and surface lesion treatment.


history of X-ray


Finally, Roentgen received the first Nobel Prize in physics in the year 1901. When asked about his thoughts on X-ray discovery, he replied, “I didn’t think, I investigated.” 

Although scientists like Nikola Tesla, Thomas Edison, and William J. Morton reported side effects from radiation exposure, the use of X-rays was uncontrollable and widespread. 

You will be surprised to hear that the detectives flaunted the use of Roentgen devices to follow unfaithful spouses. Even the lead underwear was manufactured to stop repeated attempts of peeking with “X-ray glasses.” The shoe stores as well offered free X-rays during the 1930s and 1940’s so that the customers could view their feet’ bones.

At present, we are completely aware of the risks of using industrial X-ray equipment. Hence, we have developed proper protocols to reduce unnecessary exposure to X-rays. 

Cold cathode tube or Crookes tube were used for X-ray generation till 1920. Later, it was proved to be unreliable and completely replaced by a heated-cathode tube named Coolidge tube. The constant emission of X-rays is easily possible in the Coolidge tube.

Moreover, the discovery of X-rays became a cornerstone that paved the way for the development of varied imaging techniques, computed radiography (CR), digital radiography, and many others. 


Development of Industrial X-ray 

Currently, X-ray technology is not just used in the medical sector. It is used in the industrial sectors, hence the name industrial X-ray test. The manufacturers use industrial X-rays to analyze samples for the presence of defects if any. Next, X-ray devices are used in airports as airport security scanners.

Detection of minute flaws within a short duration can be highly tedious for humans. One needs the right skills and experience to do this job. Human interpretation cannot be completely reliable at times. Moreover, it can be time-consuming as well as error-prone. This is where the industrial X-ray test helps to view the internal structure of the sample product using X-rays and determine defects within a short duration. For example, an X-ray test can inspect pressure vessels and valves for any issues in the petrochemical sector.


history of X-ray


Industrial X-ray testing is a non-destructive testing method that can detect internal defects without causing any damage to the complex sample. It can deliver quick results without any errors. Moreover, an X-ray test can measure the dimensions of the test sample as well and maintain a record of the results. 

Only a surface preparation is enough to conduct this test. Either this X-ray device can be placed in the field or at an elevated position. It is completely portable.

However, the principle of industrial X-ray inspection is similar to medical X-ray tests. The lower the wavelength, the more the penetration. Since X-rays have lesser than 100 nanometers (nm) wavelength, it is used to pass through the denser material. 

As the X-rays penetrate the test sample, the rate of absorption by the sample varies according to the thickness and density. The areas not absorbed will look darker after developing the photographic film. Similarly, the areas exposed to reduced energy will look lighter. Hence, defects like porosity and cracks according to the changes in thickness will have dark outlines on the film. Furthermore, in industrial X-rays, X-rays are emitted with the help of an electric supply from the X-ray tube.

X-ray testing can be used in marine, petrochemicals, manufacturing, waste management, aerospace, offshore, military defense, automotive, transport, power-gen sectors.

Ultimately, an industrial X-ray test ensures the manufacturers that their products are in perfect condition before selling them. 

Industrial X-ray tests can save your time and money by inspecting industrial products like printed circuit boards (PCB), metal welds, boilers, oil and gas pipelines, vehicle and aircraft parts.

Similar to the medical X-rays, further development is noticed in the industrial X-rays as well.

Industrial X-rays are of two types:

  • Conventional (Film) X-ray test
  • Digital X-ray test

Since the film X-ray test consumes more time, a digital X-ray test is introduced where a digital X-ray detector is used instead of a film to exhibit the definitive image on a computer monitor.

Currently, there are four types of digital X-ray testing such as:

  • Computed Tomography (CT)
  • Computed Radiography (CR)
  • Real-Time Radiography (RTR)
  • Digital Radiography (DR)



Here is the upshot! Our company named Uni X-ray, which was established in the year 2002, has become a national high-tech x ray machines brand. We are engaged in the research, development, and manufacture of precision X-ray intelligent inspection technology. Our highly renowned technology is widely used in inspecting BGA, SMT, CSP, IC semiconductor components, Flip-Chip, connectors, wire, photovoltaic components, batteries, ceramic products, as well as other electronic products.

So, that’s the story of a startling brief leap with a great legacy after an accidental discovery indeed!


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