EP0345904A2 — Photostimulable phosphor and radiographic applica…

Claim 1

Independent Claim 182 words

A photostimulable rare earth metal doped barium strontium fluoride phosphor, characterized in that said phosphor is within the scope of following empirical formula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 2

Dependent Claim 182 words

A photostimulable rare earth metal doped barium strontium fluoride phosphor, characterized in that said phosphor is within the scope of following empirical formula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 3

Dependent Claim 18 words

A photostimulable phosphor according to claim 1, wherein the co-dopant is Y or Eu³⁺ or a combination thereof.

Claim 4

Dependent Claim 83 words

A photostimulable phosphor according to claim 1, wherein z is in the range 10⁻⁶ ≦ z ≦ 10⁻²; A is Eu²⁺ alone or in admixture with at least one of the members selected from the group consisting of Eu³⁺, Y, Lu and Gd, and a is in the range 0.90 ≦ a ≦ 0.96 for x in the range 0.12 ≦ x ≦ 0.17 and in the range 0.85 ≦ a ≦ 0.96 for x in the range 0.17 ≦ x ≦ 0.55.

Claim 5

Dependent Claim 20 words

A photostimulable phosphor according to claim 1, wherein A is Eu²⁺ either or not in combination with Y and/or Eu³⁺.

Claim 6

Dependent Claim 142 words

A photostimulable phosphor according to claim 1, wherein said phosphor is a mixed doped phosphor prepared by fusing for about 2 h at temperatures between 700 and 1000°C in a reducing atmosphere Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zEu wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, with "A" halide(s), wherein "A" is a co-dopant as defined in claim 1.

Claim 7

Dependent Claim 186 words

A radiation image storage panel comprising in a binder layer a photostimulable phosphor, characterized in that said phosphor is within the scope of the following empirical formula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 8

Dependent Claim 186 words

A radiation image storage panel comprising in a binder layer a photostimulable phosphor, characterized in that said phosphor is within the scope of the following empirical formula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 9

Dependent Claim 86 words

A radiation image storage panel according to claim 6, wherein wherein z is in the range 10⁻⁶ ≦ z ≦ 10⁻²; A is Eu²⁺ alone or in admixture with at least one of the members selected from the group consisting of Eu³⁺, Y, Lu and Gd, and a is in the range 0.90 ≦ a ≦ 0.96 for x in the range 0.12 ≦ x ≦ 0.17 and in the range 0.85 ≦ a ≦ 0.96 for x in the range 0.17 ≦ x ≦ 0.55.

Claim 10

Dependent Claim 22 words

A radiation image storage panel according to claim 6, wherein A is Eu²⁺ either or not in combination with Y and/or Eu³⁺.

Claim 11

Dependent Claim 29 words

A radiation image storage panel according to any of claims 6 to 8, wherein said phosphor is applied at a coverage in the range from 300 to 1500 g/m2.

Claim 12

Independent Claim 258 words

A method for recording and reproducing an X-ray image which method comprises the steps of : (1) image-wise exposing a photostimulable phosphor to X-rays, (2) photostimulating said phosphor with stimulating electromagnetic radiation selected from visible light and infrared light to release from said phosphor in accordance with the absorbed X-rays electromagnetic radiation different in wavelength characteristic from the radiation used in the photostimulation, and (3) detecting the light emitted by the photostimulation applied in step (2), characterized in that the phosphor subjected to the treatments of said steps (1) and (2) is within the scope of following empirical fomula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 13

Independent Claim 258 words

A method for recording and reproducing an X-ray image which method comprises the steps of : (1) image-wise exposing a photostimulable phosphor to X-rays, (2) photostimulating said phosphor with stimulating electromagnetic radiation selected from visible light and infrared light to release from said phosphor in accordance with the absorbed X-rays electromagnetic radiation different in wavelength characteristic from the radiation used in the photostimulation, and (3) detecting the light emitted by the photostimulation applied in step (2), characterized in that the phosphor subjected to the treatments of said steps (1) and (2) is within the scope of following empirical fomula (I) : Ba 1-x-y Sr x M y II F 2-a-b Br a X b :zA wherein : M II is at least one member selected from the group consisting of Mg and Ca; X is at least one member selected from the group consisting of Cl and I; x is in the range 0.05 ≦ x ≦ 0.55; y is in the range 0 < y < 0.05; a is in the range 0.70 ≦ a ≦ 0.96; b is in the range 0 ≦ b < 0.15; z is in the range 10⁻⁷ < z ≦ 0.15, and A is Eu²⁺ or Eu²⁺ together with one or more of the co-dopants selected from the group consisting of Eu³⁺, Y, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, La, Gd and Lu, and wherein fluorine is present stoichiometrically in said phosphor in a larger atom % than bromine taken alone or bromine combined with chlorine and/or iodine.

Claim 14

Dependent Claim 85 words

A method according to claim 10, wherein in said phosphor z is in the range 10⁻⁶ ≦ z ≦ 10⁻²; A is Eu²⁺ alone or in admixture with at least one of the members selected from the group consisting of Eu³⁺, Y, Lu and Gd, and a is in the range 0.90 ≦ a ≦ 0.96 for x in the ranges 0.12 ≦ x ≦ 0.17 and in the range 0.85 ≦ a ≦ 0.96 for x in the range 0.17 ≦ x ≦ 0.55.

Claim 15

Dependent Claim 22 words

A method according to claim 10, wherein in said phosphor A is Eu²⁺ either or not in combination with Y and/or Eu³⁺.

Claim 16

Dependent Claim 15 words

A method according to claim 10, wherein the photostimulation proceeds with a scanning laser beam.

Claim 17

Dependent Claim 25 words

A method according to claim 10, wherein the detection of the light emitted by photostimulation proceeds with a phototube providing electrical signals that are digitized.

Claim 18

Dependent Claim 16 words

A method according to claim 14, wherein after storage said signals are subjected to digital processing.

Claim 19

Dependent Claim 30 words

A method according to claim 14, wherein digital signals obtained from analog-digital conversion of the electrical signals corresponding with the light obtained through photostimulation are displayed on a cathode-ray tube.

Claim 20

Dependent Claim 23 words

A method according to claim 14, wherein digital signals are transformed into analog signals that are used to modulate a writing laser beam.

Photostimulable phosphor and radiographic application

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