Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21K—HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
  • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent materials, e.g. electroluminescent or chemiluminescent
  • C09K11/08—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
  • C09K11/77—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing rare earth metals
  • C09K11/7728—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing rare earth metals containing europium
  • C09K11/7732—Halogenides
  • C09K11/7733—Halogenides with alkali or alkaline earth metals

Definitions

• the invention relates to a method for vapor deposition of a carrier with a layer of an acicular X-ray phosphor with at least one alkali metal, and the X-ray phosphor.
• X-ray phosphor can be seen as a "placeholder" for scintillator with fluorescence and storage phosphor with emission by stimulation with laser light. Fluorescence is generally understood to mean the excitation of a phosphor with high-energy radiation (UV, X-ray) with emission of low-energy radiation (emission).
• low-energy radiation e.g. 680 ⁇ m
• storage phosphor low-energy radiation causes higher-energy emissions e.g. 420 nm triggered because the "remaining energy" was "stored" in the X-ray.
• X-ray phosphors are generally used in medical technology and non-destructive material testing. In these applications, on the one hand scintillators with spontaneous emission under X-ray excitation and on the other hand storage phosphors with formation and storage of electrons and holes with subsequent photostimulated emission (PSL) are used when irradiated with, for example, red light.
• X-ray phosphors based on alkali halides play a very special role. Examples of this are CsI: Na in the X-ray image intensifier, CsI: Tl in a-Si detectors or more recently CsBr: Eu as a storage phosphor plate, as used, for example, in Proc. of SPIE Vol. 4320 (2001), "New Needle-crystalline CR Detector" by Paul J. R. Leblans et.al, pages 59 to 67.
• M Cs or Rb
• M 1 at least one alkali metal from the group Li, Na, K, Rb and Cs
• M 11 at least one divalent metal from the group Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni
• M 111 at least one metal from the group Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, AI, Ga and In
• B an activator that contains at least one metal from the group Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd , Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, Mg, Pb, Bi, Mn and In, X, X 'and X "are the same or different and represent a
• WO 01/03156 A1 describes a production process for a stimulable storage phosphor of the general formula CsX: Eu for the composition of the phosphor for the
• Such a storage phosphor was produced from CsBr and EuBr, EuBr 3 or EuOBr
• EP 1 113 458 A1 describes a method for coating a substrate in which Eu is introduced as EuX 2 , EuX 3 and EuOX. All these phosphors have in common that the dopant is a relatively simple molecule. These simple molecules are often attached to interstitials.
• the invention is based on the object of designing an X-ray phosphor and a method for producing an acicular X-ray phosphor in such a way that an optimal light yield can be achieved.
• alkali halide phases evaporate simultaneously with an alkali halide, mixed in the vapor phase and evaporated on the support.
• use begins when the evaporator is loaded with the material to be evaporated.
• the evaporation of the phase, but the formation of the phase in the layer, cannot be found in any of the above-mentioned literature.
• the vapor deposition is carried out at temperatures between 50 ° C. and 300 ° C. and a pressure between 0.001 Pa and 3 Pa.
• a better distribution of the evaporated phases and an increase in the luminous efficacy are obtained if a temperature treatment of the phosphor layer is carried out after the evaporation and cooling, the temperature treatment after cooling preferably to room temperature in the presence of steam.
• the temperature treatment can be carried out in the range from 100 ° C. to 300 ° C. in ambient air or an inert gas.
• Cs x Eu y Br (x + 2y) can advantageously be used as the alkali halide phase and CsBr can be used as the alkali halide, so that an X-ray storage phosphor of the general formula CsBr: Cs x Eu y Br (x + 2y) forms.
• the carrier can form a storage phosphor plate with the layer of the needle-shaped X-ray phosphor.
• the alkali halide phase and the alkali halide can be mixed and introduced separately into several evaporator boats in an evaporator ship or the alkali halide phase and the alkali halide.
• the object is achieved for the X-ray phosphor by producing it according to the following formula:
• M is at least one alkali metal ion from the group Na, K, Rb and Cs , H ⁇ at least one halide from the group F, Cl, Br and I and S at least one lanthanide ion from the Group La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu.
• the invention was based on the idea of producing the alkali halide phases and simultaneously evaporating them with an alkali halide.
• the evaporation can take place from one evaporator ship or from two or more evaporator boats.
• a temperature treatment of the storage phosphor layer carried out after the evaporation and cooling leads to a better distribution of the evaporated phases and thus increases the light yield by a factor of 2-10, typically a factor of 4-5.
• the temperature treatment is effective only after cooling to room temperature in the presence of water vapor.
• the water vapor can be added to an inert gas Ar, N 2 , He, Ne, Kr, for example, or it can be in the ambient air. Direct heating up - even after cooling down after evaporation - does not improve the light output. The layer must therefore "have seen water vapor" first.
• phase material in the alkali halide Due to the pressure and temperature control during vapor deposition, needle-shaped layers are created which enable a homogeneous distribution of the phase material in the alkali halide. As a result, 100 - 800 pp of the phase material (average over the layer thickness) is sufficient to achieve an optimal light yield.
• temperatures between 50 ° C and 300 ° C and pressures between 0.001 Pa and 3 Pa are set.
• the temperature during the subsequent annealing is advantageously as high as the average substrate temperature during the vapor deposition.
• the annealing time is selected so that the desired light output is achieved.
• the alkali halides M 'and M * + may be the same or different.
• the halides H ' ⁇ , H " _ and ⁇ 0" ⁇ can be the same or different.
• the factor k can also be 0, so that “pure” phase material is obtained.
• a) 50 g of CsEuBr 3 are mixed with 550 g of CsBr and then a storage phosphor CsBr: Cs x Eu y Br (x + 2y) (needle-shaped) is produced using the usual vapor deposition method.
• b) 20 g of CsEu 2 Br 5 are mixed with 580 g of CsBr and then a storage phosphor CsBr: Cs x Eu y Br (x + 2y) (needle-shaped) is produced using the usual vapor deposition method.
• n) 30 g CsEuBr 3 and 20 g Cs 2 EuBr 4 are mixed with 550 g CsBr and then a storage phosphor CsBr: Cs x Eu y Br (x + 2y) (needle-shaped) is produced with the usual vapor deposition method, o) 60 g CsEuBr 3 and 20 g of Cs 3 EuBr 5 are mixed with 520 g of CsBr and then a storage phosphor CsBr: Cs x Eu y Br (x + y) (needle-shaped) is produced using the usual vapor deposition method.
• CsBr Cs x Eu y Br (x + 2y)
• pure CsBr can also be refilled and this mixture can then be evaporated. This can also be done several times until the CsBr: Cs x Eu y Br (x + 2y) concentration has dropped below 0.1 mol%.
• the individual substances Cs x Eu y Br (x + y) and CsBr can also be evaporated from two or more evaporator boats. Also from an evaporator Shuttles CsBr and Cs x Eu y Br (x + 2y) as a mixture and a pure substance, e.g. CsBr, can be evaporated from another.
• a europium / bromine compound (eg EuBr 2 , EuBr 3 ) can also be evaporated together with the Cs x Eu y Br (X + y) and CsBr.
• the fluorides, chlorides and / or iodides can also be used.
• Europium oxibromides e.g. EuOBr, Eu 3 0 4 Br, Eu 3 OBr 4 , Eu 4 OBr 6
• EuOBr 6 Europium oxibromides
• the oxyfluorides, oxychlorides and / or oxyiodides can also be used.
• the europium oxides (eg EuO, Eu 2 0 3 ) can also be evaporated together with the Cs x Eu y Br (x + 2y) and CsBr.
• Europium oxibromide and europium oxide can also be vaporized together with the Cs x Eu y Br (x + 2y) and CsBr.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Inorganic Chemistry (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Luminescent Compositions (AREA)
• Conversion Of X-Rays Into Visible Images (AREA)
• Physical Vapour Deposition (AREA)

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• 2003
  • 2003-07-18 AU AU2003250307A patent/AU2003250307A1/en not_active Abandoned
  • 2003-07-18 US US10/522,318 patent/US7189426B2/en not_active Expired - Fee Related
  • 2003-07-18 EP EP03787686A patent/EP1527150A2/de not_active Withdrawn
  • 2003-07-18 JP JP2004528391A patent/JP2005534790A/ja active Pending
  • 2003-07-18 WO PCT/DE2003/002429 patent/WO2004017352A2/de not_active Ceased

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