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Reusable X-ray film – is real saving during the radiographic inspection.

Radiographic inspection of welds and castings is the main method of quality and reliability control. This relates, first of all, to that the method doesn’t require any sample preparation, and the information about dimensions and spatial position of the flaws , when using up-to-date methods of digital radiography, could be received practically in real time mode.  However, this type of control is one of the most expensive. The main components of cost price (up to 90%) are consumables – X-ray film, chemical reagents for its development and working time of the staff. To develop films the darkroom is required. There is also the problem of waste utilization that is generated during the development.

Russian and foreign industry was actively working on the reduction of cost price of radiographic inspection. X-ray television systems appeared that allowed obtaining the internal image of weld directly on the PC display without using the X-ray film. Unfortunately, X-ray TV sets are big and heavy, which hampers their use. The quality of the image, obtained on X-ray television systems is also inferior to the quality of X-ray film.

The up-to-date level of digital systems development resulted in the appearance of brand new technology in which succeeded to combine easiness, flexibility, quality and convenience of X-ray film with high efficiency of X-ray television systems. This technology got the scientific name CR (COMPUTER RADIOGRAPHY) or “technology of flexible phosphorous plates” and or popular name “reusable X-ray film”.

CR (COMPUTER RADIOGRAPHY) – is a technique allowing obtaining X-ray image on phosphorous plates for the subsequent reading and visualization.

The method is based on the property of some luminophors to accumulate the latent image under the influence of X-ray or gamma radiation, long-term store this image and further release the energy, kept by phosphor, in form of light within the visible range when exposing to red laser radiation (phenomenon of photoluminescence).. As the up-to-date computers are applied to read the latent image, the method got the name of computer or digital radiography.

In the computer radiography to get the image the special reusable plate (hereinafter referred to as phosphorous plate) is used. It represents a flexible polyethylene plate on which the special X-ray sensitive layer is applied. Such plates are available of variable dimensions (e.g. 6x10, 10x24, 18x24, 30x40, 10x152 etc.), including rolls of up 1.5m long. You can yourself cut the plates of necessary size by using ordinary cutter.

The control pattern is arranged like in traditional radiography. The phosphorous plate is fixed to the weld or to other object. The flexibility allows its bending according to the object shape. It is possible to use available lead shields and cassettes. Then the exposure with any source of X-ray or gamma radiation takes place. It is possible to use X-ray units of constant potential, pulsed and half-wave units as well as gamma-isotopes of selenium, iridium, cesium, cobalt and others. Plates are compatible with any sources of radiation with energy from 10 keV to 25 MeV. 

As the sensitivity of FOSFOMATIC plate is much higher than that of X-ray film the exposure time could be reduced in 5-10 times, which saves the life time of expensive X-ray tube and reduces significantly the radiation-absorbed dose of the staff..

You don’t need anymore any development and darkroom. After the exposure the phosphorous plate is inserted to the special reading-erasing device FOSFOMATIC straight in the light. The reading process takes from 20 second to 5 minutes depending on the plate size and spatial resolution. The information appears immediately on the computer monitor and is memorized in database. After reading the phosphorous plate is erased and becomes prepared for re-use. The service life of the plate depends on external factors (cleanliness, carefulness, scanner quality), but not on the plate itself (luminescent life of the plate makes up 60000 exposures). In real operation conditions one plate could be used more than 10 000 times!

Tests, carried out in different laboratories (TESTRON, KODAK, PROMETEY, IZHORA PLANTS) shown that the quality of image, obtained on standard KODAK FlexHR plates is equivalent to that obtained on popular fine-grain X-ray film AGFA D4, which allows their use even in such critical fields like aircraft/rocket and nuclear industries.

According to its dynamic range (10 times more than the X-ray film has) FOSFOMATIC exceeds not only the X-ray television but the radiography as well.  With its help it is possible to fix the object image, having big difference in thickness (valves) per one exposure (instead of 5-7 exposures for the film), with subsequent viewing of the zones of different optical density by adjusting brightness and contrast of the image. Differing from the film the image could be improved, filed and sent by e-mail. 

The digital processing on PC monitor allows the adjustment of the image brightness and contrast as well as carrying out the digital filtering in order to improve the image quality. Simple but powerful software for the image visualization allows focusing on the imperfection zones.  Special algorithms of flaws detection make the work of operator easier and quicker. There is a possibility to define the pipe wall thickness and corrosion level using special algorithm. The software has convenient control protocol. All this accelerates and facilitates the work of operator. The database on ordinary DVD allows keeping of thousands of images and instantaneous finding the necessary one.

FOSFOMATIC combines such properties like mobility of flexible phosphorous plates, highest quality of X-ray film, large dynamic range, high working speed, digital data processing and absence of expensive consumables; the installation of the system and the training of specialists taking less than one day.

When evaluating the economic efficiency of the FOSFOMATIC systems implementation it has to take into account that in this case there is no need in X-ray film, chemical reagents, equipment for the film development and drying, premises for films storage etc.
On a national basis this allows the saving of tens of USD millions due to the complete renunciation of using expensive consumables and significant reduction in working time, necessary to get god results.   
For the technology FOSFOMATIC working documents, methodic instructions, quality performance charts are developed. All main certificates and permissions are received: Rostechnadzor, Prometey, Minatom, Rosstandard.

Actually the use of FOSFOMATIC is permitted at most part of industry branches, including: 
- power engineering machine building
- equipment and pipelines of nuclear power plants
- steel castings for nuclear power plants
- оobjects of boiler inspection
- gas supply systems
- lifting facilities
- equipment for oil and gas industry
- equipment for metallurgical industry
- equipment for shipbuilding industry

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