EP0249660A1
Expired / Lapsed
EP
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A process for the conversion of x-rays
Assignee: Agfa Gevaert NV
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Filing: 1986-06-16
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Granted: —
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Expires: 2006-06-16
Abstract
Abstract A process for the conversion of X-rays into green light with a phosphor which on exposure to X-rays emits light the spectrum of which is dominated by a group of higher intensity lines occurring between 530 and 570 nm, characterized in that said phosphor comprises a silicate of gadolinium activated with terbium, the atomic percentage of terbium substituted for gadolinium being in the range from 0.6 to 7.5, and the silicate consisting for at least 90 mole % of the oxyorthosilicate. The invention is directed particularly to the use of said phosphor in an X-ray conversion screen suited for use in medical radiography.
Inventors
- 👤 Marinus Jacobus Lammers
- 👤 George Blasse
- 👤 David Richard Terrell
- 👤 Lodewijk Marie Neyens
- 👤 Nikolaas Cyriel De Jaeger
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 17:57
CPC Classifications
G; G21; G21K; G21K4/00; C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/77742
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
81 words
A process for the conversion of X-rays into green light with a phosphor which on exposure to X-rays emits light the spectrum of which is dominated by a group of higher intensity lines occurring between 530 and 570 nm, characterized in that said phosphor comprises a silicate of gadolinium activated with terbium, the atomic percentage of terbium substituted for gadolinium being in the range from 0.6 to 7.5, and the silicate consisting for at least 90 mole % of the oxyorthosilicate.
Claim 2
Dependent Claim
81 words
A process for the conversion of X-rays into green light with a phosphor which on exposure to X-rays emits light the spectrum of which is dominated by a group of higher intensity lines occurring between 530 and 570 nm, characterized in that said phosphor comprises a silicate of gadolinium activated with terbium, the atomic percentage of terbium substituted for gadolinium being in the range from 0.6 to 7.5, and the silicate consisting for at least 90 mole % of the oxyorthosilicate.
Claim 3
Dependent Claim
23 words
A process according to claim 1 wherein the silicate content of the phosphor consists for at least 96 mole % of the oxyorthosilicate.
Claim 4
Dependent Claim
52 words
A process according to claim 1 or 2, wherein the phosphor is activated with trivalent terbium in an atomic percentage in the range of from 0.8 to 6.0 with respect to its total rare earth metal concentration, and the Gd₂O₃/SiO₂ molar ratio used in the phosphor preparation is from 1.03 to 1.50.
Claim 5
Dependent Claim
40 words
A process according to any of claims 1 to 3, wherein the phosphor is prepared as a mixture of said terbium activated gadolinium oxyorthosilicate (Gd₂SiO₅) with gadolinium oxide (Gd₂O₃), wherein the gadolinium oxide content does not exceed 56 mole %.
Claim 6
Dependent Claim
69 words
An X-ray conversion screen consisting essentially of a phosphor dispersed in particulate form in a supported or self-supporting binder layer wherein the binder is of organic nature, characterized in that said phosphor comprises a silicate of gadolinium activated with terbium, the atomic percentage of terbium substituted for gadolinium being in the range from 0.6 to 7.5, and the silicate consisting for at least 90 mole % of the oxyorthosilicate.
Claim 7
Dependent Claim
69 words
An X-ray conversion screen consisting essentially of a phosphor dispersed in particulate form in a supported or self-supporting binder layer wherein the binder is of organic nature, characterized in that said phosphor comprises a silicate of gadolinium activated with terbium, the atomic percentage of terbium substituted for gadolinium being in the range from 0.6 to 7.5, and the silicate consisting for at least 90 mole % of the oxyorthosilicate.
Claim 8
Dependent Claim
25 words
An X-ray conversion screen according to claim 5, wherein the silicate content of the phosphor consists for at least 96 mole % of the oxyorthosilicate.
Claim 9
Dependent Claim
53 words
An X-ray conversion screen according to claims 5 and 6, wherein the phosphor is activated with trivalent terbium in an atomic percentage in the range of 0.8 to 6.0 with respect to its total rare earth metal concentration, and the Gd₂/O₃/SiO₂ molar ratio used in the phosphor preparation is from 1.03 to 1.70.
Claim 10
Dependent Claim
26 words
An X-ray conversion screen according to any of the claims 5 to 7, wherein the phosphor is in dispersed form in (a) film forming organic polymer(s).
Claim 11
Dependent Claim
32 words
An X-ray conversion screen according to any of the claims 5 to 8, wherein the phosphor in said layer is applied at a coverage in the range from 300 to 750 g/m2.
Claim 12
Dependent Claim
28 words
An X-ray conversion screen according to any of the claims 5 to 9, wherein the phosphor has a particles size in the range of 0.1 to 20 um.
References Cited (Backward Citations)
No citation records indexed.
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