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Roentgen X-Ray Generator Diode Vacuum Electron Tube Circuit Electronics

OddMix.com - Technology Note - TN1207 - Karl Nagy

Warning! - Higher voltages are dangerous! - Never use both hands at the same time while working on high voltage circuits! - Disconnect power from a circuit when work on it! Think carefully when around high voltages! X-Ray and all ionizing radiation are dangerous! Be extra careful and use shields at all times respect all warnings!

Picture 1. 1G3GT 1B3GT X-Ray Emitter Vacuum Tube [8 KB]
Picture 1. 1G3GT 1B3GT X-Ray Emitter Vacuum Tube

Be extremely careful when ANY circuit is activated and possibly radiating. X-Ray radiation intensity is inversely proportional to the square of the distance from its source. The farter away is one from the X-Ray emitter the safer it will be. Do NOT apply power to ANY X-Ray emitters even to potential ones without adequate shielding! Before ANY circuit experiments enclose all potential sources with a metal surrounds used as a shield before application of power. The higher the applied working voltage for the vacuum tube used, the harder, more penetrating the resulting X-Ray produced would be.

Picture 2. X-Ray Danger Warning [10 KB]
Picture 2. X-Ray Danger Warning

A prominent German physicist Wilhelm Roentgen had discovered Roentgen rays in 1895, while working with the then new cathode ray tube [CRT]. He observed that metals emitted powerful, penetrating, unknown, new rays. The new radiation was named Roentgen [Röntgen or Roentgen] rays in honor of his discovery all around the world except in some English speaking countries were Roentgen rays are still called X-Rays.

It was demonstrated that X-rays have no electrical charge since they are not deflected by magnetic or electric fields. When cathode rays are striking a metal at high velocity they slow down, while their target emits new, different, Roentgen rays.

Laue in 1912 successfully demonstrated X-Ray interference and proved that Roentgen rays are a high-energy light. The wavelength of the X-Rays falls between 3x1016 to 3x1019 Hz within the electromagnetic spectrum and indeed behave similarly to the visible light. Roentgen rays are most known and used for non-invasive examinations in health and other sciences.

Figure 1. Braun Tube Experimental Setup [3 KB]
Figure 1. Braun Tube Experimental Setup

Occasionally a production of X-rays is required to test an instrument. With a simple HV [High Voltage] rectifier tube like the 1B3GT, 1G3GT, 1J3, 1K3, 2X2 and many others that built for HV service will work. All that is necessary beside the tube is a HV power source - Picture 1. The power source in its simplest form can be a standard automobile ignition transformer.

All vacuum tubes built to handle high voltages are capable to produce X-Rays, some more so then others. High vacuum tubes are much better for experimentation. It is difficult and expensive to produce good, hard vacuum so many of the tube producers did the minimum effort that still worked. The quality of the vacuum produced in a vacuum tube that makes the difference between a passable and a great electron tube. It was discovered during the early television days that the picture tube of the TV set and some of the high voltage tubes are X-Ray producers. Many high voltage rectifier tubes carry a warning against Roentgen rays - Picture 2.

Contrary to popular believe it does NOT require to have a hot emitter within a vacuum tube for conduction within the trapped residual gases and to produce cathode and other types of rays. The first experiments that used the original Braun type evacuated tube - Figure 1. - that was similar to what professor Röntgen used to discover the X-Rays were all without hot cathodes. When a glass tube with two electrodes at its opposite ends that are connected to a voltage supply is also connected to a vacuum pump at different levels of vacuum the tube exhibit various glows of many different intensity and color.

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