Autoradiography Film

Autoradiographic film is typically used to create accurate images that are scanned into digital format for presentation and publication. The autoradiographic film has a low background and high contrast for improved sensitivity to low signals. Double-immersion autoradiographic films for improved performance and consistent results. Autoradiographic films are recommended for use in automatic processors and manual development methods.

Autoradiographic films are photographic films designed for x-ray photography. They are roughly divided into two categories: direct photographic films (sensitization screen type and non-sensitization screen type) and indirect photographic films. Automatic radiographic films are mainly medical x-ray films and industrial x-ray films by application. Medical X-ray films use a light blue film base to prevent halo. Fluorescent sensitization screens can be added to stimulate fluorescence for better results. Industrial X-ray films require fine grain, low haze, high contrast, high density, and high resolution. There are also radiographic films for measuring radiation dose and, in a broader sense, films for x-ray photographic reproduction. Photographic emulsions are usually applied to both sides of the base of direct photographic films to improve sensitivity and contrast.

In 1895, the German physicist Roentgen used his discovery of X-rays to take the first photographs of human hand bones. The first industrial radiography laboratory was designed and built in 1922 at the Watertown Arsenal in the United States. After more than 80 years of development, X-ray inspection technology has been widely used in medical diagnosis, aerospace, aviation, military, nuclear energy, petroleum, electronics, machinery, archaeology, and many other fields. Among them, X-ray film photography technology has been developed and matured due to the simple principle, and flexible operation, as the earliest invention and use of radiographic detection technology widely used in all aspects of people's production and life.

a. High resolution to improve the identification of defects.

b. High sensitivity to X-rays (especially medical X-ray films) with high sensitivity requirements to minimize the amount of X-ray radiation and to prevent human victims.

c. Easy to use, easy to process.

d. The film should be evenly coated and free of stains to avoid confusion with defective images. X-rays must be coated with a high-sensitivity, high-contrast blind emulsion on both sides of the film base to improve the utilization of X-rays and enhance image contrast.

Autoradiography refers to the use of the nature of the different degrees of absorption of radiation when the radiation penetrates the object to be examined, and the radiation is projected on the film and developed to obtain a photograph showing the change in thickness and internal defects of the object. Automatic radiography mainly includes X-ray or gamma radiography techniques.

Automated radiography is a method that uses X-rays or gamma rays to inspect materials and workpieces, and uses radiographic film as a recording medium and display method. Radiographic inspection uses the many characteristics of X-rays and gamma rays (e.g., light sensitivity) to determine the presence of internal defects in materials and workpieces by observing the attenuation of X-rays or gamma rays recorded (light sensitive) on radiographic films (negatives), and thus assess the quality and use value of the materials and workpieces without destroying or damaging them. This is done without damaging or destroying the material or workpiece.

X-rays and gamma rays are both electromagnetic waves. X-rays and gamma rays have many distinctive characteristics, such as a refraction coefficient close to 1, almost no refraction; strong penetrating ability; interference and diffraction phenomena only in crystal grating; ionization, fluorescence, heat, and photochemistry with certain substances; easy to attenuate, and for different substances and densities, the attenuation coefficient is different; easy to kill Biological cells, destruction of biological tissue, etc.

X-rays are a kind of radiation that is emitted when a high-speed charged particle hits metal and is accompanied by a sharp deceleration under the action of the Coulomb field of the metal nucleus. The intensity of X-rays is related to the tube voltage (kV) of the X-rays tube, the higher the tube voltage, the higher the intensity of X-rays and the greater their penetrating power. The same is true for accelerators. In short, the intensity of X-rays can be controlled.

In 1896, less than two months after Roentgen's announcement of the discovery, Combeil Swindon of London, England, was the first to use X-ray fluoroscopy of metal to find internal defects. In the same year, Wright of Yale University also used X-rays to examine steel welds with a plate thickness of 4 nm and successfully detected welding defects; Germany took radiographic negatives of submarine cables. The X-ray tubes used at that time were cold cathode type so-called Crookes tubes. This is a pump to pump the internal low-pressure glass bubble, there are two electrodes, through the induction coil to apply a limited high voltage, so the penetration power is very small. 1908 Kampel discussed the possibility of using X-ray-beaten electrons to imaging, Mössingdier shot the frog legs action of the ray activity film, and the original film is still preserved.

In 1913, William Coolidge announced the discovery of a new type of X-ray tube (called the Coolidge tube, or hot-cathode electron-ray tube). In the same year, the Gator vacuum pump appeared, and the vacuum level of the tube was to meet the requirements. 1916, the General Electric Company Institute in New York, New York (where the Colledge tube was invented) tried to use sensitized film + fluorescent sensitized screen transillumination plate thickness of 12.7nm oxyacetylene gas welding seam, in the negative found unfused, not welded through and porous defects. Radiography as a means of quality evaluation, the first appearance, the development of welding methods, and technology have played a role in pushing the wave.

In 1932, the United States introduced another new Coleridge tube in the market that could work continuously at 300kV and 20mA. In 1933, Britain made a 400kV, 20mA ray machine, which made the conventional X-ray machine with transformer accelerated electrons, in the use of two types of sensitization --- lead foil sensitization and fluorescence sensitization, on steel, can obtain 75mm and 110mm penetration respectively. The new takeoff of industrial radiography began around 1933. This year, the United States General Electric Company launched the first generation of industrial ultra-high energy X-ray equipment. First was the 1MV resonant transformer with a multi-electrode ray tube, and then the 2MV ray machine. In 1942, Britain acquired four 1MV machines, one of which was installed in Woolwich and operated until 1979. During 36 years of continuous use, the ray tube was replaced only once. In 1941, Kester developed the first generation of electron cyclotrons, one of which was supplied to Invereweich for experiments the following year. The machine was able to operate at 4.5 MeV, but the X-ray output was very small. Soon afterward, the United States and Sweden made more powerful instruments, some of which were used for industrial radiography.

In the early 1950s, Van de Graaff developed electrostatic start gas pedals (referred to as "static plus"), many of which were used for radiography in the United States, while there were only a few in the United Kingdom. At the same time, the U.S. Varian and British Dynamix introduced a 1-25 MeV electron linear gas pedal ("direct plus"), because of the strong X-ray output, the "back plus" was gradually eliminated. Most of them are stationary, but there are also portable ones.

Gamma rays (i.e., gamma rays) are a type of radiation emitted along with the spontaneous decay of radioisotopes. Gamma rays for radiographic detection are mainly from radioisotope sources such as cobalt 60 (Co-60), cesium 137 (Cs-137), iridium 192 (Ir-192), and thulium 170 (Tm-170). The intensity of gamma rays is related to the volume of the radioisotope source, the larger the volume of the source, the greater the intensity of gamma rays, and the stronger its penetrating ability. Since the volume of the radioisotope source varies with decay, the intensity of gamma rays cannot be controlled.
Depending on the way of ray generation, radiography can be divided into X-ray radiography with X-ray tubes as the source and gamma radiography with radioisotopes as the source.

Just six weeks after the discovery of X-rays, the French physicist Henri Becquerel discovered that certain heavy elements emit penetrating rays. At first, while studying the chemical properties of uranium salts in his laboratory, he was always puzzled by the graying of the light-sensitive material placed in the drawer. He participated in the verification of "Roentgen rays" and repeated Roentgen's experiments with fluorescent substances. He found that the photographic plate placed near this fluorescent screen would produce a gray haze, even if the Röntgen rays were cut off. Finally, he was convinced of what we now call radioactivity. This discovery directly triggered the research of the Curie couple and the discovery of radium. Becquerel soon realized that the rays emitted by uranium salts had the same physical properties and similar characteristics as the X-rays discovered by Roentgen. Becquerel is known to have taken radiographic negatives of aluminum badges with " rays, while Madame Curie transilluminated one of her purses, and the discovery of gamma rays was largely not explored in new ways for the next 30 years, probably because radium is only available in small quantities in nature.

The first scientific report on γ-ray for industrial radiography was published in 1925 by Payson and Labut, and the object of the inspection was the damaged turbine castings. From 1929-1930, Britain, the United States, France, and Germany's ray inspection workers almost at the same time, respectively, with a radium source of the large thickness of cast steel parts and welded seams for γ radiographic inspection, and published the experimental results. British Woolwich used a 242mg radium salt source in a tube with an effective diameter of 3.5mm and a length of 14mm. at that time the cost of radium was 10 British pounds per mg, so a source at that time could be described as a sky-high price. The exposure time was usually at least 1 hour.

In 1938, Dulwich had 3 radium sources, and in 1940, the U.S. Department of the Navy had 11 radium sources with a total weight of 2.8 g. In 1941, the American Radium and X-Ray Society was founded, whose main purpose was to exchange information about industrial radiography. Later, this society was renamed as American Society for Non-Destructive Testing and Inspection. 1952-1953, the radon source manufacturing plant was closed down when the man-made radioisotope sources were introduced by the Ing Harwell Atomic Energy Research Center. In the 1950s, along with the emergence of artificial radioisotope sources, industrial radiography technology developed significantly, and each company searched for different radioactive sources for radiographic inspection technology. γ-rays can be used for parts that cannot be illuminated by X-ray or are not economical to illuminate. Although its transmission quality is rarely as good as the X-ray negative, there are many applications are still recognized.

If you are interested in our autoradiography film or have any questions, please write an e-mail to info@antiteck.com, we will reply to you as soon as possible.