(Hf1-x Zrx)3 P2 O11 luminescent material, method of preparation and X-ray intensifying screen containing same

Claim 2

A luminescent material having the oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 : P 2 O 5 and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 , where x is within the range of 0 to 0.5, said luminescent material exhibiting a peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays.

Claim 3

The process of claim 1 wherein about 30 mole percent of MgF 2 is added.

Claim 4

The luminescent material of claim 1, consisting essentially of large, single crystalline particles.

Claim 5

A process for producing a luminescent material having the oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 : P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 , where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, the process comprising: a. first forming a mixture of compounds selected from the group consisting of (Hf 1-x Zr x )O 2 , P 2 O 5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf 1-x Zr x )O 2 :P 2 O 5 within the range of about 2.85 to 3.15; and b. firing the mixture at a temperature within the range of about 1400° to 2,200° C, for a time sufficient to result in a luminescent material having said characteristic peak.

Claim 6

A process for producing a luminescent material having the oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 : P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 , where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, the process comprising: a. first forming a mixture of compounds selected from the group consisting of (Hf 1-x Zr x )O 2 , P 2 O 5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf 1-x Zr x )O 2 :P 2 O 5 within the range of about 2.85 to 3.15; and b. firing the mixture at a temperature within the range of about 1400° to 2,200° C, for a time sufficient to result in a luminescent material having said characteristic peak.

Claim 7

The process of claim 4 wherein x is within the range of about 0 to about 0.25.

Claim 8

The process of claim 4 wherein prior to firing, the mixture is: a. heated at least once to a temperature within the range of from about 260° to 500° C for about 1 to 16 hours, in order to insure removal of at least a portion of contained volatile material, followed by b. comminuting and blending the heated mixture to a relatively uniform powder mixture.

Claim 9

An x-ray intensifying screen for use with conventional silver halide emulsion x-ray film to intensify an exposed image on the film, the screen comprising: a. a base layer of a material substantially transparent to x-rays, but substantially opaque to visible and ultraviolet radiation; and b. a layer of an x-ray excitable luminescent material secured to base layer, characterized in that the luminescent material consists essentially of particles having the oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 :P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 where x is within the range of 0 to 0.5, said luminescent material exhibiting a peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, whereby good resolution of the image is obtained without substantial crossover.

Claim 10

An x-ray intensifying screen for use with conventional silver halide emulsion x-ray film to intensify an exposed image on the film, the screen comprising: a. a base layer of a material substantially transparent to x-rays, but substantially opaque to visible and ultraviolet radiation; and b. a layer of an x-ray excitable luminescent material secured to base layer, characterized in that the luminescent material consists essentially of particles having the oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 :P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 where x is within the range of 0 to 0.5, said luminescent material exhibiting a peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, whereby good resolution of the image is obtained without substantial crossover.

Claim 11

The x-ray intensifying screen of claim 7 wherein x is within the range of about 0 to 0.25.

Claim 12

X-ray intensifying screen of claim 7 wherein the (Hf 1-x Zr x ) 3 P 2 O 11 consists essentially of large single crystalline particles.

Claim 13

A process for producing a luminescent material having an oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 :P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 , where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, and the material consisting essentially of large single-crystalline particles, the process comprising: a. first forming a mixture of compounds selected from the group consisting of (Hf 1-x Zr x )O 2 , P 2 O 5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf 1-x Zr x )O 2 :P 2 O 5 within the range of about 2.85 to 3.15; b. adding from about 10 to 100 mole percent of magnesium fluoride to the mixture; and c. firing the mixture at a temperature within the range of about 1200° to 1600° C for a time sufficient to result in a luminescent material having said characteristic peak.

Claim 14

A process for producing a luminescent material having an oxide composition of 3:1 molar proportions of (Hf 1-x Zr x )O 2 :P 2 O 5 , and the empirical formula (Hf 1-x Zr x ) 3 P 2 O 11 , where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, and the material consisting essentially of large single-crystalline particles, the process comprising: a. first forming a mixture of compounds selected from the group consisting of (Hf 1-x Zr x )O 2 , P 2 O 5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf 1-x Zr x )O 2 :P 2 O 5 within the range of about 2.85 to 3.15; b. adding from about 10 to 100 mole percent of magnesium fluoride to the mixture; and c. firing the mixture at a temperature within the range of about 1200° to 1600° C for a time sufficient to result in a luminescent material having said characteristic peak.

Claim 15

The process of claim 10 wherein x is within the range of about 0 to 0.25.

Claim 16

The process of claim 10 wherein prior to firing, the mixture is: a. heated at least once to a temperature within the range of from about 260° to 500° C for about 1 to 16 hours, in order to insure removal of at least a portion of contained volatile material, followed by b. comminuting and blending the heated mixture to a relatively uniform powder mixture.

Claim 17

The process of claim 10 wherein about 30 mole percent of MgF 2 is added to the mixture prior to firing.