EP0182105A1 - Scintillation crystal and method of making it - Google Patents
Scintillation crystal and method of making it Download PDFInfo
- Publication number
- EP0182105A1 EP0182105A1 EP85113232A EP85113232A EP0182105A1 EP 0182105 A1 EP0182105 A1 EP 0182105A1 EP 85113232 A EP85113232 A EP 85113232A EP 85113232 A EP85113232 A EP 85113232A EP 0182105 A1 EP0182105 A1 EP 0182105A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- crystal
- cooling
- scintillation
- thick
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000013078 crystal Substances 0.000 title claims description 60
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 239000000463 material Substances 0.000 claims abstract description 29
- 238000002844 melting Methods 0.000 claims abstract description 11
- 230000008018 melting Effects 0.000 claims abstract description 11
- 238000001816 cooling Methods 0.000 claims description 18
- 239000000758 substrate Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 13
- 238000001704 evaporation Methods 0.000 claims description 6
- 230000008020 evaporation Effects 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 230000001788 irregular Effects 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 2
- 238000007738 vacuum evaporation Methods 0.000 claims description 2
- 239000011734 sodium Substances 0.000 description 10
- 230000005855 radiation Effects 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 4
- 230000005499 meniscus Effects 0.000 description 4
- 239000005297 pyrex Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000005538 encapsulation Methods 0.000 description 2
- 239000003129 oil well Substances 0.000 description 2
- NJXPYZHXZZCTNI-UHFFFAOYSA-N 3-aminobenzonitrile Chemical compound NC1=CC=CC(C#N)=C1 NJXPYZHXZZCTNI-UHFFFAOYSA-N 0.000 description 1
- 241001572615 Amorphus Species 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000005388 borosilicate glass Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 230000016776 visual perception Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/20—Measuring radiation intensity with scintillation detectors
- G01T1/202—Measuring radiation intensity with scintillation detectors the detector being a crystal
Definitions
- the invention relates to scintillation crystals.
- crystal includes bodies which are used as scintillators; such bodies may be single crystal, polycrystalline, amorphous, etc.
- the invention relates to thick scintillation crystals, i.e. crystals which are sufficiently thick that a large fraction of radiation incident on the crystal loses all its energy in tne crystal as a result of interactions with it.
- thick scintillation crystals are at least 1/4 to 3/8 inch thick when used in gamma cameras, and may be several inches thick when used for oil well logging, background monitoring, and other applications.
- Thin scintillation crystals have thicknesses on the order of hundreds of microns and are used for example in X-ray equipment.
- Thick scintillation crystals are traditionally grown as large single crystals. This is slow and expensive. Furthermore, the growth process requires large and expensive furnaces, and substantial machining is required to cut and polish the rough scintillation crystal into an appropriate form for mounting and encapsulation.
- Thick scintillation crystals have also been produced by evaporation of CsI(Na).
- the end product of this manufacturing process is a thick crystal with a needle-like polycrystalline structure. Crystals so produced are unusable for applications in which the incident radiation is gamama rays, because the crystals are not clear enough, have poor conversion efficiency, and poor energy resolution.
- One object of the invention is to produce a thick scintillation crystal without requiring the large and expensive furnaces needed to produce grown crystals.
- a further object is to provide a thick scintillation crystal which is optically clear enough for use in applications such as oil-well logging, etc.
- Yet a further object is to provide a thick scintillation crystal which can be produced more cost effectively than known thick scintillation crystals.
- Yet still another object is in general to improve over the prior art.
- scintillation material is heated either close to or at its melting point for between 4 and 10 hours. Thereafter, the material is cooled to room temperature.
- the cooling is in two steps, the first being to cool the crystal to a temperature of about 400° C at one predetermined rate, and the second being to cool the crystal down to room temperature at another faster rate.
- the material is maintained slightly below its melting point. This produces an optically translucent scintillation crystal having a crystal structure in which there are many optically visible irregularly shaped domains, i.e. irregularly shaped domains which can be visually perceived with the unaided eye.
- the crystal is ready for encapsulation after it has been cooled down.
- the scintillation material is actually melted and held at its melting point.
- the crystal so produced has a meniscus at its edge; the meniscus should be ground off before the crystal can be used.
- An oven generally indicated by reference numeral 2 has an insulated housing 4, a bottom 5, and a cover 6. Inside the oven 2 is a heater 8 which is controlled by appropriate external circuitry (not shown). The heater 8 is preferably electrical, but this is not part of the invention.
- a horizontal support 10 with an open center is located inside the oven 2 above the heater 8.
- the housing 4 is cylindrical so the support 10 is annular, but the shapes of the support 10 and housing 4 are not part of the invention.
- a substrate 12 is placed on top of the support 10. Suitable materials for the . substrate 12 include quartz, high purity A1203, aluminum, Pyrex glass, lime glass or borosilicate glass, but other materials may be utilized. If the finished scintillation crystal described below is to be fixed to this substrate (as for use in a gamma camera) the substrate 12 must be of a material which is transparent to gamma radiation.
- a layer 14 of scintillation material such as CsI(Na) is placed on top of the substrate 12.
- the layer 14 may be produced in a separate vacuum evaporation oven (not shown) and then laid on the substrate 12, or may merely be raw scintillation material in powdered form.
- the layer 14 may be produced in a vacuum evaporator which contains an appropriate heating means such as oven 2. It is advantageous if the oven 2 is provided with appropriate evaporation equipment because this reduces handling, but this is not part of the invention.
- the interior of the oven 2 is filled with argon or other nonreactive gas having a low continuous flow. This keeps oxygen out of the oven 2.
- the layer 14 of scintillation material is heated and then cooled down to room temperature.
- Tnree preferred examples are set forth below:
- a thick uniform layer 14 of CsI(Na) scintillation material produced by evaporation and having the characteristic needle-like crystal structure is heated in a uniform manner (i.e. in an environment containing the minimum feasable temperature gradient) from room temperature to approximately 617 0 C (i.e. to within approximately 5° C of its melting point of 622° C). This heating step is carried out linearly over a period of between 2 and .6 hours, 4 hours being presently preferred.
- the layer 14 After the layer 14 has been heated to the desired temperature, it is held at that temperature for between approximately 4 and 10 hours. The lower the temperature to which the layer 14 is heated, the longer must the layer 14 be so held. If the layer 14 is kept at the desired temperature for too long, the sodium in the scintillation material might evaporate, because of its vapor pressure.
- the layer 14 After the layer 14 has been heated for an appropriate period, it is cooled down linearly to approximately 400° C over approximately 8 hours. Thereafter, it is cooled down to room temperature. This final cooling step is preferably carried out linearly over 4 hours, but this is non-critical. It is not necessary that cooling be carried out in two steps, but this is preferred because this reduces the time required for cooling. The cooler the crystal, the faster the rate at which it can be cooled down without breaking; the second cooling step therefore proceeds more rapidly than does the first.
- the cooled layer 14 of CsI(Na) is a thick scintillation crystal of uniform thickness, characterized by many small optically visible (i.e. as by visual perception with the unaided eye) domains having irregular shapes. Each domain has a diameter which at most approximates the thickness of the layer 14 (see Fig. 2). The diameters increase with the temperature to which the layer 14 is heated and the length of time during which heating is carried out.
- the crystal is optically translucent, has a conversion efficiency of approximately 90%, and an energy resolution of approximately 12% for 122 keV gamma radiation.
- a dish-shaped substrate 12 made of thin (approximately 1 mm) Pyrex glass is used to support a thick uniform layer 14 of CsI(Na) scintillation material produced by evaporation and having the characteristic needle-like crystal structure.
- the layer 14 is uniformly heated to its melting point of 622° C at the same rate as in Example I above and held in its liquid state for between 4 and 10 hours. The layer 14 is then cooled in the two steps described in Example I above.
- the scintillation material in the layer 14 has a different coefficient of expansion than does the Pyrex dish used as the substrate 12.
- either the substrate 12 or the layer 14 (preferably the substrate 12) cracks and the finished thick scintillation crystal may be separated from the Pyrex substrate 12.
- the finished scintillation crystal is optically transparent and has an amorphous crystal structure.
- the conversion efficiency is approximately 60-70% and the energy resolution is approximately 13% for 122 keV gamma radiation.
- the finished thick scintillation crystal it is desirable for the finished thick scintillation crystal to be uniformly (i.e. gaplessly) bonded to a substrate.
- a thicker and/or,stronger substrate 12 is used and the cooling process is carried out more slowly for a longer time, such as 16 hours.
- the CsI(Na) is somewhat rubbery and accommodates itself to the stresses of cooling and generally no breakage occurs.
- the scintillation material in the layer 14 is liquified during melting, a meniscus remains upon cooling on the upper periphery of the layer 14 and this should be removed (as by grinding) prior to use of the finished scintillation crystal.
- a mixture of CsI and NaI powders of appropriate proportions (in the range of 0.040 mole percent Na to 0.220 mole percent Na) is placed in the dish-shaped substrate of Example II above. This mixture is of sufficient depth to create a thick layer 14.
- the mixture is uniformly heated and cooled as in Example II above.
- the finished thick scintillation crystal is optically transparent, has an amorphus crystal structure, a conversion efficiency of 60% - 85% and an energy resolution of 13% for 122 keV gamma radiation. There is a meniscus which should be removed, as in Example II above.
- the scintillation material will not be melted, because the conversion efficiency and energy resolution are better where melting has not taKen place.
- the invention is not restricted to any particular scintillation material, CsI(Na) being only preferred. NaI(Tl) may be used as the scintillation material, as may any other appropriate compound.
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Molecular Biology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Luminescent Compositions (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Measurement Of Radiation (AREA)
Abstract
Scintillation material is heated either at or slightly below its melting point. The material is held at that temperature for 4 to 10 hours, and is cooled down to room temperature, preferably in two steps.
Description
- The invention relates to scintillation crystals. (The term "crystal" includes bodies which are used as scintillators; such bodies may be single crystal, polycrystalline, amorphous, etc.) More particularly, the invention relates to thick scintillation crystals, i.e. crystals which are sufficiently thick that a large fraction of radiation incident on the crystal loses all its energy in tne crystal as a result of interactions with it. In practice, thick scintillation crystals are at least 1/4 to 3/8 inch thick when used in gamma cameras, and may be several inches thick when used for oil well logging, background monitoring, and other applications. Thin scintillation crystals have thicknesses on the order of hundreds of microns and are used for example in X-ray equipment.
- Thick scintillation crystals are traditionally grown as large single crystals. This is slow and expensive. Furthermore, the growth process requires large and expensive furnaces, and substantial machining is required to cut and polish the rough scintillation crystal into an appropriate form for mounting and encapsulation.
- Thick scintillation crystals have also been produced by evaporation of CsI(Na). The end product of this manufacturing process is a thick crystal with a needle-like polycrystalline structure. Crystals so produced are unusable for applications in which the incident radiation is gamama rays, because the crystals are not clear enough, have poor conversion efficiency, and poor energy resolution.
- For applications requiring very thick crystals, optical clarity is an important characteristic, because the clearer is a scintillation crystal, the less attenuated is the scintillation light generated in it. To produce thick scintillation crystals with the required optical clarity, conventionally grown scintillation crystals have been required. This is highly expensive.
- One object of the invention is to produce a thick scintillation crystal without requiring the large and expensive furnaces needed to produce grown crystals.
- A further object is to provide a thick scintillation crystal which is optically clear enough for use in applications such as oil-well logging, etc.
- Yet a further object is to provide a thick scintillation crystal which can be produced more cost effectively than known thick scintillation crystals.
- Yet still another object is in general to improve over the prior art.
- In accordance with the invention, scintillation material is heated either close to or at its melting point for between 4 and 10 hours. Thereafter, the material is cooled to room temperature. Advantageously, the cooling is in two steps, the first being to cool the crystal to a temperature of about 400° C at one predetermined rate, and the second being to cool the crystal down to room temperature at another faster rate.
- In one advantageous embodiment, the material is maintained slightly below its melting point. This produces an optically translucent scintillation crystal having a crystal structure in which there are many optically visible irregularly shaped domains, i.e. irregularly shaped domains which can be visually perceived with the unaided eye. The crystal is ready for encapsulation after it has been cooled down.
- In a second advantageous embodiment, the scintillation material is actually melted and held at its melting point. This produces an optically transparent crystal with an amorphous crystal structure. The crystal so produced has a meniscus at its edge; the meniscus should be ground off before the crystal can be used.
- In accordance with the invention, there is produced a new thick scintillation crystal.
- The invention will be better understood with reference to the following drawing and the detailed description of preferred embodiments.
- Exemplary and non-limiting preferred embodiments of the invention are shown in the drawings, in which:
- Fig. 1 is a schematic cross-sectional drawing of apparatus in accordance with the invention; and
- Fig. 2 schematically illustrates the appearance of a preferred embodiment.
- An oven generally indicated by
reference numeral 2 has an insulated housing 4, abottom 5, and acover 6. Inside theoven 2 is aheater 8 which is controlled by appropriate external circuitry (not shown). Theheater 8 is preferably electrical, but this is not part of the invention. - A
horizontal support 10 with an open center is located inside theoven 2 above theheater 8. In this example, the housing 4 is cylindrical so thesupport 10 is annular, but the shapes of thesupport 10 and housing 4 are not part of the invention. A substrate 12 is placed on top of thesupport 10. Suitable materials for the . substrate 12 include quartz, high purity A1203, aluminum, Pyrex glass, lime glass or borosilicate glass, but other materials may be utilized. If the finished scintillation crystal described below is to be fixed to this substrate (as for use in a gamma camera) the substrate 12 must be of a material which is transparent to gamma radiation. - A
layer 14 of scintillation material such as CsI(Na) is placed on top of the substrate 12. Thelayer 14 may be produced in a separate vacuum evaporation oven (not shown) and then laid on the substrate 12, or may merely be raw scintillation material in powdered form. Alternatively, thelayer 14 may be produced in a vacuum evaporator which contains an appropriate heating means such asoven 2. It is advantageous if theoven 2 is provided with appropriate evaporation equipment because this reduces handling, but this is not part of the invention. The interior of theoven 2 is filled with argon or other nonreactive gas having a low continuous flow. This keeps oxygen out of theoven 2. - In accordance with the invention, the
layer 14 of scintillation material is heated and then cooled down to room temperature. Tnree preferred examples are set forth below: - A thick
uniform layer 14 of CsI(Na) scintillation material produced by evaporation and having the characteristic needle-like crystal structure is heated in a uniform manner (i.e. in an environment containing the minimum feasable temperature gradient) from room temperature to approximately 6170 C (i.e. to within approximately 5° C of its melting point of 622° C). This heating step is carried out linearly over a period of between 2 and .6 hours, 4 hours being presently preferred. - After the
layer 14 has been heated to the desired temperature, it is held at that temperature for between approximately 4 and 10 hours. The lower the temperature to which thelayer 14 is heated, the longer must thelayer 14 be so held. If thelayer 14 is kept at the desired temperature for too long, the sodium in the scintillation material might evaporate, because of its vapor pressure. - After the
layer 14 has been heated for an appropriate period, it is cooled down linearly to approximately 400° C over approximately 8 hours. Thereafter, it is cooled down to room temperature. This final cooling step is preferably carried out linearly over 4 hours, but this is non-critical. It is not necessary that cooling be carried out in two steps, but this is preferred because this reduces the time required for cooling. The cooler the crystal, the faster the rate at which it can be cooled down without breaking; the second cooling step therefore proceeds more rapidly than does the first. - The cooled
layer 14 of CsI(Na) is a thick scintillation crystal of uniform thickness, characterized by many small optically visible (i.e. as by visual perception with the unaided eye) domains having irregular shapes. Each domain has a diameter which at most approximates the thickness of the layer 14 (see Fig. 2). The diameters increase with the temperature to which thelayer 14 is heated and the length of time during which heating is carried out. The crystal is optically translucent, has a conversion efficiency of approximately 90%, and an energy resolution of approximately 12% for 122 keV gamma radiation. - A dish-shaped substrate 12 made of thin (approximately 1 mm) Pyrex glass is used to support a
thick uniform layer 14 of CsI(Na) scintillation material produced by evaporation and having the characteristic needle-like crystal structure. Thelayer 14 is uniformly heated to its melting point of 622° C at the same rate as in Example I above and held in its liquid state for between 4 and 10 hours. Thelayer 14 is then cooled in the two steps described in Example I above. - The scintillation material in the
layer 14 has a different coefficient of expansion than does the Pyrex dish used as the substrate 12. When cooled as set forth above, either the substrate 12 or the layer 14 (preferably the substrate 12) cracks and the finished thick scintillation crystal may be separated from the Pyrex substrate 12. - The finished scintillation crystal is optically transparent and has an amorphous crystal structure. The conversion efficiency is approximately 60-70% and the energy resolution is approximately 13% for 122 keV gamma radiation.
- In some cases, it is desirable for the finished thick scintillation crystal to be uniformly (i.e. gaplessly) bonded to a substrate. To achieve this objective, a thicker and/or,stronger substrate 12 is used and the cooling process is carried out more slowly for a longer time, such as 16 hours. The CsI(Na) is somewhat rubbery and accommodates itself to the stresses of cooling and generally no breakage occurs.
- Because the scintillation material in the
layer 14 is liquified during melting, a meniscus remains upon cooling on the upper periphery of thelayer 14 and this should be removed (as by grinding) prior to use of the finished scintillation crystal. - A mixture of CsI and NaI powders of appropriate proportions (in the range of 0.040 mole percent Na to 0.220 mole percent Na) is placed in the dish-shaped substrate of Example II above. This mixture is of sufficient depth to create a
thick layer 14. - The mixture is uniformly heated and cooled as in Example II above. The finished thick scintillation crystal is optically transparent, has an amorphus crystal structure, a conversion efficiency of 60% - 85% and an energy resolution of 13% for 122 keV gamma radiation. There is a meniscus which should be removed, as in Example II above.
- In general, where very thick scintillation crystals are required, the scintillation material will be melted, because optical clarity becomes more important to performance in thicker crystals.
- Where the crystals are thinner, the scintillation material will not be melted, because the conversion efficiency and energy resolution are better where melting has not taKen place.
- The invention is not restricted to any particular scintillation material, CsI(Na) being only preferred. NaI(Tl) may be used as the scintillation material, as may any other appropriate compound.
- Those skilled in the art will understand that changes can be made in the preferred embodiments here described, and that these embodiments can be used for other purposes. Such changes and uses are within the scope of the invention, which is limited only by the claims which follow.
Claims (18)
1. An optically translucent scintillation crystal having a structure characterized by a plurality of optically visible irregular domains.
2. An optically transparent scintillation crystal having an amorphous structure.
3. An optically translucent crystal of CsI(Na) having a structure characterized by a plurality of optically visible . irregular domains.
4. An optically transparent crystal of CsI(Na) having an amorphous structure.
5. The crystal of claims 1, 2, 3 or 4, wherein the crystal is thick.
6. A method of making a thick scintillation crystal, comprising the steps of:
forming a thick layer of a meltable scintillation material;
heating said layer to a temperature below the melting point of said material;
maintaining said layer at said temperature for between approximately 4 and 10 hours; and
cooling said layer to room temperature.
7. The method of claim 6, wherein said material is CsI(Na).
8. The method of claim 6, wherein said forming step is carried out by evaporation.
9. The method of claim 6, wherein said cooling step comprises the steps of cooling the layer to approximately 400° C at a first rate and subsequently cooling the layer to room temperature at a second and faster rate.
10. The method of claim 7, wherein said temperature is . approximately 617° C.
11. A method of making a thick scintillation crystal, comprising the steps of:
forming a thick layer of a meltable scintillation material;
heating said layer to its melting point;
maintaining said layer at said melting point for between approximately 4 and 10 hours; and
cooling said layer to room temperature.
12. The method of claim 11, wherein the material is CsI(Na).
13. The method of claim 11, wherein said forming step is carried out by evaporation.
14. The method of claim 11, wherein said forming step is carried out by laying down a layer of powder which includes CsI and NaI mixed together.
15. The method of claim 11, wherein said cooling step comprises the steps of cooling the layer to approximately 400° C at a first rate and subsequently cooling the layer to room temperature at a second and faster rate.
16. The method of claim 11, wherein said material is held in a frangible vessel and said cooling step is carried out in a manner that a likelihood of breakage of the vessel is maximized.
17. The method of claim 11, wherein said material is laid on a substrate and said cooling step is carried out in a manner that said material is uniformly bonded to said substrate.
18. The method of claims 8 or 13, wherein said forming step is carried out by vacuum evaporation.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/667,304 US4663187A (en) | 1984-11-01 | 1984-11-01 | Scintillation crystal and method of making it |
US667304 | 1984-11-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0182105A1 true EP0182105A1 (en) | 1986-05-28 |
Family
ID=24677675
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85113232A Withdrawn EP0182105A1 (en) | 1984-11-01 | 1985-10-18 | Scintillation crystal and method of making it |
Country Status (2)
Country | Link |
---|---|
US (1) | US4663187A (en) |
EP (1) | EP0182105A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7057187B1 (en) * | 2003-11-07 | 2006-06-06 | Xradia, Inc. | Scintillator optical system and method of manufacture |
US7482602B2 (en) * | 2005-11-16 | 2009-01-27 | Konica Minolta Medical & Graphic, Inc. | Scintillator plate for radiation and production method of the same |
JP6179925B2 (en) * | 2014-08-27 | 2017-08-16 | 国立研究開発法人理化学研究所 | Radiation detection element, radiation detection apparatus, and method of manufacturing radiation detection element |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB792071A (en) * | 1955-02-24 | 1958-03-19 | Armour Res Found | Improvements in or relating to scintillation material and methods of making same |
FR2319908A1 (en) * | 1975-07-28 | 1977-02-25 | Hitachi Medical Corp | GAMMA CAMERA SPARKLER |
FR2360989A1 (en) * | 1976-08-03 | 1978-03-03 | Thomson Csf | RADIOLOGICAL IMAGE INTENSIFIER, AND ITS MANUFACTURING PROCESS |
DE3345450A1 (en) * | 1982-12-16 | 1984-06-20 | Siemens AG, 1000 Berlin und 8000 München | Arrangement of a scintillation crystal and a carrier, and method for producing such an arrangement |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US30156A (en) * | 1860-09-25 | Cheese-vat | ||
US2149076A (en) * | 1935-10-18 | 1939-02-28 | Massachusetts Inst Technology | Method for the manufacture of crystalline bodies |
US3693018A (en) * | 1966-12-27 | 1972-09-19 | Varian Associates | X-ray image intensifier tubes having the photo-cathode formed directly on the pick-up screen |
US3795531A (en) * | 1970-02-03 | 1974-04-05 | Varian Associates | X-ray image intensifier tube and method of making same |
US3961182A (en) * | 1970-02-03 | 1976-06-01 | Varian Associates | Pick up screens for X-ray image intensifier tubes employing evaporated activated scintillator layer |
US4044082A (en) * | 1971-09-13 | 1977-08-23 | The Harshaw Chemical Company | Multiple extrusion of polycrystalline extrudates |
US4313257A (en) * | 1979-11-19 | 1982-02-02 | General Electric Company | Annealing methods for improving performance of a radiation sensor |
-
1984
- 1984-11-01 US US06/667,304 patent/US4663187A/en not_active Expired - Lifetime
-
1985
- 1985-10-18 EP EP85113232A patent/EP0182105A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB792071A (en) * | 1955-02-24 | 1958-03-19 | Armour Res Found | Improvements in or relating to scintillation material and methods of making same |
FR2319908A1 (en) * | 1975-07-28 | 1977-02-25 | Hitachi Medical Corp | GAMMA CAMERA SPARKLER |
FR2360989A1 (en) * | 1976-08-03 | 1978-03-03 | Thomson Csf | RADIOLOGICAL IMAGE INTENSIFIER, AND ITS MANUFACTURING PROCESS |
DE3345450A1 (en) * | 1982-12-16 | 1984-06-20 | Siemens AG, 1000 Berlin und 8000 München | Arrangement of a scintillation crystal and a carrier, and method for producing such an arrangement |
Also Published As
Publication number | Publication date |
---|---|
US4663187A (en) | 1987-05-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Rubin | A shock-metamorphic model for silicate darkening and compositionally variable plagioclase in CK and ordinary chondrites | |
US4180618A (en) | Thin silicon film electronic device | |
US4650540A (en) | Methods and apparatus for producing coherent or monolithic elements | |
Novak et al. | The production of EFG sapphire ribbon for heteroepitaxial silicon substrates | |
US4663187A (en) | Scintillation crystal and method of making it | |
US4311743A (en) | Semiconductor-glass composite material and method for producing it | |
Holton et al. | Synthesis and melt growth of doped ZnSe crystals | |
EP0123809A2 (en) | Process for growing a large single crystal from multiple seed crystals | |
Warren | Procedures and apparatus for zone purification of the alkali halides | |
EP0400266B1 (en) | Apparatus for manufacturing single silicon crystal | |
Van Valkenburg et al. | Synthesis of mica | |
US4784715A (en) | Methods and apparatus for producing coherent or monolithic elements | |
CN1283852C (en) | Method for growing gadolinium silicate scintillation crystal | |
US3503717A (en) | Crystallization at high pressure to prevent self diffusion of materials | |
CN1046004C (en) | Descent method for growing large size cesium iodide (CSI) crystal | |
CN113930842A (en) | Preparation method of cerium-doped lithium lutetium borate crystal | |
US2584427A (en) | Process of sealing glass to sapphire | |
CN1062317C (en) | Vertical temperature gradient method for growing lithium aluminate and lithium gallate crystals | |
CN106757353A (en) | The growing method of bismuth germanate single crystal | |
CN109457296B (en) | Preparation method and device of cerium doped lanthanum bromide | |
CN111893557A (en) | Thermal barrier device for isolating heat and smelting furnace | |
GB1572915A (en) | Crystallisation device | |
US4540550A (en) | Apparatus for growing crystals | |
JPS6051694A (en) | Manufacture of bismuth germanate single crystal with high scintillation response | |
JPH07309691A (en) | Production of crystal and producing device therefor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB NL |
|
17P | Request for examination filed |
Effective date: 19860626 |
|
17Q | First examination report despatched |
Effective date: 19880113 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Withdrawal date: 19890405 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: STOUB, EVERETT W. Inventor name: PERSYK, DENNIS E. |