Silver-containing lithium heptaborate photostimulable phosphor, method for producing same, and laminate using said photostimulable phosphor
View Patent ↗The present invention aims to provide a photostimulable phosphor for obtaining a two-dimensional or three-dimensional dosimeter, the photostimulable phosphor exerting superior handleability, exhibiting superior biological equivalence, and having superior precision. The present invention also aims to provide a laminate using the photostimulable phosphor. The aforementioned objects are achieved by means of a method for producing a photostimulable phosphor, the method comprising a step A for mixing lithium tetraborate, boron oxide and silver oxide and a step B for obtaining the photostimulable phosphor comprising lithium heptaborate as a base material and silver as a luminescent center present in the base material by firing the aforementioned mixture at 820 to 860° C., wherein the molar ratio between the lithium tetraborate and the boron oxide in the step A is X:1 (X>1), and the amount of the silver oxide is 0.06 to 1.0 mass % relative to the total mass of the lithium tetraborate and the boron oxide.
1. A method for producing a photostimulable phosphor, comprising:
a step A for mixing lithium tetraborate, boron oxide and silver oxide, and
a step B for obtaining the photostimulable phosphor comprising lithium heptaborate as a base material and silver as a luminescent center present in the base material by firing the mixture at 820 to 860° C.,
wherein the molar ratio between the lithium tetraborate and the boron oxide in the step A is X:1, provided that X>1, and the amount of the silver oxide is 0.06 to 1.0 mass % relative to the total mass of the lithium tetraborate and the boron oxide.
2. The method of claim 1 , wherein the X is 2 to 4.
3. The method of claim 1 , wherein the temperature of the firing is 840 to 860° C. and the time of the firing is 6 hours or more.
4. The method of claim 1 , wherein the amount of the silver oxide is 0.06 to 0.08 mass %.
5. A photostimulable phosphor comprising lithium heptaborate as a base material and silver as a luminescent center present in the base material, the photostimulable phosphor having a monomodal luminescence spectrum.
6. The photostimulable phosphor of claim 5 which has a monomodal luminescence spectrum with a maximum value at a range of 300 to 310 nm.
7. A plate comprising the photostimulable phosphor of claim 5 .
8. A photostimulable phosphor sheet which comprises the photostimulable phosphor of claim 5 and has a thickness of 0.05 to 1 mm.
9. A thin film body comprising 0.1 to 5 mm-thick paper or biological tissue-equivalent plastic sheet and the photostimulable phosphor sheet of claim 8 which is laminated on the paper or the sheet.
10. A method for producing the thin film body of claim 9 , comprising:
a step C for preparing a powder of the photostimulable phosphor,
a step D for forming a flowable binder layer on the paper or biological tissue-equivalent plastic sheet,
a step E for retaining the powder obtained in the step C in the flowable binder layer obtained in the step D by placing the powder on the surface of the flowable binder layer, and
a step F for solidifying the flowable binder layer.
11. The method of claim 10 , wherein the flowable binder in the step D is a thermosetting resin and the thermosetting resin is cured in the step F.
12. A laminate comprising a biological tissue-equivalent plastic plate and the photostimulable phosphor sheet of claim 8 or thin film body of claim 9 which is laminated on the plastic plate.