Intensifier Screens

A Real Time X-Ray Inspection System is introduced to replace Film X-Ray. The main objective is to reduce the consumption of film and to reduce the environmental pollution due to lead intensifying screens and chemicals. Other benefits are the reduction of space to storage X-ray data and the shorter inspection time, which gives a faster feed back to production. 

For further information about intensifying screens, see Radiography in Modern Industry, Eastman Kodak Co., X-ray Division, Rochester, N. Y., second edition, 1957. 

Integrating capacitor in PXQ, 256 Integrating detectors, 43, 44 Intensifying screens, 12, 13, 44... 

Intensifying screens (for X rays and in industrial nondestructive testing)... 

Following immersion of the glass slides in a 1.0 (w/v) BSA-BSA solution to a depth of 2.1 cm for 30 min at 21°C, the slides were thoroughly rinsed in PBS by dilution/displacement. The slides were then completely immersed in PBS, where they were kept for different lengths of time, i.e., for 1, 2, 4, and 16 hrs. Thereafter, the slides were removed and air-dried and placed on X-ray film between Lanex Intensifying Screens as described above. The supernatants from these diffusion experiments were then concentrated 10 times by evaporation in order to establish their radioactive content. 

Laskey RA, Mills AD. 1977. Enhanced autoradiographic detection of P and I using intensifying screens and hyper-sensitized film. FEBS Lett 82 314-316. 

Sensitivity of X-ray films can be increased by use of an intensifying screen or by pre-flashing. The following protocol describes autoradiography using intensifying screen and solid scintillation, respectively. 

Open an X-ray film cassette in a dark room illuminated with a weak green or red light. Mount the intensifying screen, place a piece of X-ray film on it, and lay the dry gel or membrane on top. If no radioactive ink or radioactive labeled markers are used, prick a needle through gel and film to allow identification of the exact position of the gel after development. 

Expose the dry gel to X-ray film in a cassette with intensifying screen at -70 °C as described above. 

Screen Preparations, 100 micron thick x-ray intensifying screens were prepared using standard doctor blade coating techniques. The final phosphor volume was 50% when the coatings were dried. In most instances, the phosphor suspensions were prepared using polyvinyl butyral binders with viscosities adjusted to 2000 centipoise for the doctor blade operation and care was taken to avoid convection cell formation (9). A cross section of the screen construction is shown in Figure I. The completed screens consist of polyester (Mylar) base about 10 mil. thick, a 50 micron thick (TI02 (rutile) reflector layer, a 100 micron thick phosphor layer, a 10 micron thick clear cellulose acetate butyrate top protective layer. 

To be used in x-ray intensifying screens, rare earth phosphors must also have high conversion efficiencies (nc Figure 1) in addition to high intrinsic absorptions of x-rays and suitable emission characteristics. The several rare earth phosphors listed in Table I have conversion efficiencies from about 10% for La202S Tb to about 20% for LaOBr Tb (5,, ) as compared to about 6% for CaWOi. ... 

Screen-Film Systems. According to Ludwig (5), crucial to the application of x-ray phosphors for intensifying screens is the efficiency with which the incident x-ray energy is converted to useful light energy as given by the expression ... 

For wide angle scattering, flat film camera with appropriate film back and intensifying screen (Fig. 21.6)... 

Yttrium tantalate and yttrium niobate-tantalate have good X-ray absorption and are used in X-ray intensifying screens because of their high conversion factor (Section 5.5.4.2.). Substitution of tantalum by small quantities of niobium considerably increases the blue fluorescence when excited by X rays. 

The advantage of the X-ray excitable tantalates lies in the fact that the emission spectrum extends into the near UV. The films used with X-ray intensifying screens are particularly sensitive in this region. 

Oxyhalides. The oxyhalides of yttrium, lanthanum, and gadolinium are good host lattices for activation with other rare-earth ions such as terbium, cerium, and thulium. The use of LaOCl Tb3+ as the green component in projection-television tubes has been discussed [5.419]. LaOBr Tb3+ and LaOBr Tm3+ exhibit high X-ray absorption, and they are used in X-ray intensifying screens [5.420]. 

Intensifying screens consist of cardboard or plastic sheets (e.g., polyester) as substrates. A reflective layer (e.g., TiOz) is first applied to this and then the phosphor-binder layer. 

Secure the blot strips to a sheet of Whatman 3MM paper using Photomount or other spray-on adhesive, and then autoradiograph at —70°C using prefogged X-ray film and an intensifying screen (5)... 

Laskey, R A. (1980) The use of intensifying screens or orgamc scintillators for visualizing radioactive molecules resolved by gel electrophoresis. Methods Enzymol 65,363-371... 

Laskey, R. A. and Mills, A. D. (1977) Enhanced autoradiographic detection of 32P and l25I using intensifying screens and hypersensitized film. FEES Lett 82,314—316... 

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