CN105908257A

CN105908257A - Calcium and ytterbium ion co-doped YAG ultra-fast scintillation crystal and preparation method thereof

Info

Publication number: CN105908257A
Application number: CN201610407716.2A
Authority: CN
Inventors: 陈建玉; 侯晴; 齐红基; 韩和同; 宋朝辉; 张侃
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2016-06-12
Filing date: 2016-06-12
Publication date: 2016-08-31
Anticipated expiration: 2036-06-12
Also published as: CN105908257B

Abstract

The invention discloses a calcium and ytterbium ion co-doped YAG ultra-fast scintillation crystal and a preparation method thereof. The chemical formula of calcium and ytterbium ion co-doped YAG crystal is Ca3xYb3yY3(1-x-y)Al5O12, wherein x is equal to 0.0001-0.01, y is equal to 0.05-0.3, x is the doping amount of Ca ions, y is the doping amount of Yb ions, and Ca ions and Yb ions enter crystal to replace Y ion sites. The prepared Ca3xYb3yY3(1-x-y)Al5O12 ultra-fast scintillation crystal has the advantages of being high in photoyield, strong in irradiation damage resistance and the like, and can be applied in the field of ultra-fast pulse radiation detection, inertial confinement nuclear fusion, space radiation detection, nuclear reaction kinetics research and the like.

Description

Calcium ytterbium ion is co-doped with YAG fast flashing crystal and preparation method thereof

Technical field

The present invention relates to scintillation crystal, it is brilliant that particularly a kind of calcium ytterbium ion is co-doped with YAG fast flashing Body and preparation method thereof.

Background technology

Inorganic scintillation crystal is that one can be by high-energy photon (X/ gamma-rays) or particle (proton, neutron etc.) Energy be converted into be prone to detection ultraviolet/visible light son crystalline state energy transfer medium.Scintillation crystal does The detector become is widely used in high-energy physics, nuclear physics detecting and imaging, nuclear medical imaging diagnosis (XCT, PET), geological prospecting, the astronomical field such as Space Physics and safety random check.Along with core Detection and the developing rapidly of correlation technique, the application of scintillation crystal is constantly widened.Different application Field proposes requirements at the higher level to scintillation crystal, and traditional NaI (Tl), BGO, PWO etc. flash Crystal cannot meet the requirement of high-performance scintillation detector.

Ultrafast pulse radiometric technique typically requires that the current signal that detector system exports can be use up The temporal information of radiation field may be reflected truly, be find out material inner core course of reaction information and The important technical of advanced radiation appliance performance.Require that Inorganic scintillation detector has the fastest Time resolution characteristics and moderate photoyield.According to ultrafast pulse radiometric technique, the time is decayed Specific demand, typically luminescence decay time is referred to as fast flashing less than the scintillation crystal of 10ns brilliant Body,

Fast flashing body combination property is one of key factor determining ultrafast detector performance.Table 1 It is that Basic Physical Properties and the scintillation properties parameter of at present conventional fast flashing material compares.From table In can find, subnanosecond can be reached organic scintillator (such as BC422Q) time response the soonest, but Its density and atomic number are relatively low, thus gamma/neutron resolution capability (often below 1 times) is the most weak In inorganic scintillator (typically at 5～20 times), it is unfavorable for the gal in gamma, neutron mixed radiation field Horse radionetric survey.Inorganic scintillator meets subnanosecond arteries and veins time response typically more than tens nanoseconds The crystal rushing radiation detection technology requirement is little.BaF₂Crystal can reach sub-nanosecond temporal response, but BaF₂Crystal also has the slow light-emitting components of 620ns while having the fast composition of 0.6ns, and this is slow Composition share is higher, limits the application in ultrafast pulse radiation detection of this crystal；Yb:YAP It is less than 1ns die-away time, and light output is of a relatively high, but YAP crystal is owing to having complexity Orthogonal perovskite structure, crystal growing process easily ftractures, in addition to being difficult to prepare large-size crystals, Another major defect is that the perovskite structure of YAP crystal lattice distortion makes crystals easily be formed greatly The point defect of amount, crystal overstrike under high-energy ray irradiation, light output drastically declines.

The Fundamental Physical Properties of fast flashing material commonly used by table 1 and scintillation properties compares

For meeting the demand of ultrafast pulse radiation detection application, it is thus achieved that easily preparation, physical and chemical performance are stable Novel inorganic scintillator material become current fast flashing body development major trend.In recent years, The Yb inorganic ultrafast crystal of doping based on Yb electric charge transfer luminous mechanism causes domestic and international colleague's Pay much attention to.Wherein, the YAG crystal of Yb admixture is to have the one that typical charge transfer is luminous Ultrafast inorganic scintillation crystal.The ultrafast crystal of Yb:YAG has following features: 1) emission wavelength is positioned at The coupling such as photomultiplier tube near 350nm and 550nm and currently used is good；2) due to Optical attenuation time τ ＜ 1ns at temperature and its room temperature of concentration effect, and there is no slow light emitting elements.

Although the die-away time of Yb:YAG crystal is very fast, have in inorganic scintillation crystal definitely Advantage.But its luminescence yield is relatively low, only 1250Ph/MeV, this severely limits Yb:YAG Application as the inorganic fast flashing crystal of superior performance.Before not reducing crystal die-away time Putting, the study mechanism and the realization rate that improve Yb:YAG crystal photoyield are international material educational circles The hot issue paid close attention to pulsed radiation detection field.

Summary of the invention

In order to solve the deficiency of the photoyield of above-mentioned Yb:YAG fast flashing crystal, the mesh of the present invention Be provide one be co-doped with YAG SuperFlash for ultrafast pulse radiation detection field calcium ytterbium ion Bright crystal and preparation method thereof, this crystal is capable of higher concentration Yb³⁺Ion doping, and have High light yield, is the high temperature ultrafast inorganic scintillation crystal material of a kind of excellent performance.

The technical solution of the present invention is as follows:

A kind of calcium ytterbium ion is co-doped with YAG fast flashing crystal, and feature is that this crystal is to use melt Method grows, and its chemical formula is:

Ca_3xYb_3yY_3(1-x-y)Al₅O₁₂

In formula, x=0.0001～0.005, y=0.05～0.3, x is dopant ion Ca²⁺, it replaces YAG Y in parent lattice³⁺Ion.

A kind of calcium ytterbium ion is co-doped with the preparation method of YAG fast flashing crystal, under the method includes Row step:

1. composition of raw materials:

The YAG crystal that calcium ytterbium ion is co-doped with, i.e. Ca_3xYb_3yY_3(1-x-y)Al₅O₁₂Crystal the most former Material uses CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃: >=99.999%, Al₂O₃:≥ 99.999%, 3x:3y/2:3 (1-x-y)/2:5/2 carries out dispensing, the wherein value of x, y in molar ratio Scope is respectively x=0.0001～0.01, y=0.05～0.3；

2. melt method for growing Ca is used_3xYb_3yY_3(1-x-y)Al₅O₁₂Scintillation crystal:

First by the most predrying for each high pure oxide powder, removing absorption water, calcination temperature is 1000 DEG C, by molar ratio weighing CaO: >=99.99%, Yb after selected x, y value₂O₃:≥ 99.999%, Y₂O₃: >=99.999%, Al₂O₃: >=99.999% raw material.Raw material is sufficiently mixed all Use isostatic pressing machine briquet after even, be then charged in alumina crucible, put in Muffle furnace and sinter, Being warming up to 1300 DEG C with 10 hours, constant temperature was cooled to room temperature through 10 hours after 10 hours, Block is taken out and puts into crucible, the employing above-mentioned monocrystal of melt method for growing:

Described melt method is czochralski method, and described crucible material is iraurite, seed crystal be<111>or <100>the pure YAG seed crystal in direction, crystal growth is carried out in high-purity Ar atmosphere.Pull rate Being 0.5～5mm/h, rotary speed is 10～30rpm.

Described melt method is Bridgman-Stockbarger method, and described crucible material uses high purity graphite, crucible Seed crystal can not be put in bottom, or puts into the pure YAG seed crystal described in above-mentioned czochralski method, and crystal is raw Length is carried out in high-purity Ar atmosphere.Crucible fall off rate is 0.1～1.5mm/h.

Described melt method is temperature gradient method, and crucible material uses molybdenum or tungsten-molybdenum alloy, earthenware Can not put seed crystal bottom crucible, or put into the pure YAG seed crystal described in above-mentioned czochralski method, crystal is raw Length is carried out in high-purity Ar atmosphere, with the rate of temperature fall fall that crystal growth rate is 0.1～100 DEG C/h Temperature also grows crystal.

The technique effect of the present invention:

High-quality Ca is grown with above raw material and technique_3xYb_3yY_3(1-x-y)Al₅O₁₂Crystal, crystal Water white transparency, outward appearance is good, has excellent optics and physical and chemical performance, Ca ion concentration to be doped into 1at%；The photoyield of this crystal is 3800Ph/MeV, and Yb (15at%): YAG's 1250Ph/MeV compares, and improves about 2 times；This crystal die-away time is 0.422ns, substantially protects Hold constant.

Ca_3xYb_3yY_3(1-x-y)Al₅O₁₂Fast flashing crystal can set with photodetections such as silicon photo diodes Standby efficient coupling, can apply ultrafast pulse radiation detection, inertial confinement fusion, space radiation to visit The fields such as survey, nuclear reaction kinetics research.

Detailed description of the invention

Below by being embodied as, the invention will be further described, but should not limit the present invention with this Protection domain.

Embodiment 1: Czochralski grown Ca²⁺Doping content is 0.01at%, Yb³⁺Doping content is 5% Ca_0.0003:Yb_0.15Y_2.8497Al₅O₁₂Scintillation crystal

First by the most suitable for each high pure oxide powder predrying, remove absorption water, Calcination 10h at 1000 DEG C, then by CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃:≥ 99.999%, Al₂O₃: >=99.999% raw material carries out weighing according to mol ratio, dispensing.Raw material is abundant Use isostatic pressing machine briquet after mix homogeneously, be then charged in alumina crucible, put Muffle furnace into Middle sintering, was warming up to 1300 DEG C with 10 hours, and constant temperature was lowered the temperature through 10 hours after 10 hours To room temperature, block is taken out and puts into Iridium Crucible；Use Czochralski grown Ca_0.0003:Yb_0.15Y_2.8497Al₅O₁₂Fast flashing crystal: do insulation material with zirconium oxide and aluminium oxide, Sealing observation panel with gem sheet, seed crystal is the pure YAG seed crystal in<111>direction, and crystal growth is at height Pure Ar atmosphere is carried out.The pull rate of crystal is 0.9mm/h, and rotary speed is 14-30rpm, Controlling the growth of crystal Raised key axis, growth temperature is 1970 DEG C.Crystal growth is through shove charge → evacuation → applying argon gas → temperature increasing for melting materials → roasting crystal seed → sow → necking down → shouldering → isodiametric growth → carry de-and The processes such as cooling, whole growth cycle about 9 days.Grow the colourless of a size of Φ 50*100mm Transparent Ca_0.0003:Yb_0.15Y_2.8497Al₅O₁₂Crystal, crystal weighs about 1200g.

Embodiment 2: Czochralski grown Ca²⁺Doping content is 0.05at%, Yb³⁺Doping content is The Ca of 15%_0.0015:Yb_0.45Y_2.5485Al₅O₁₂Scintillation crystal

First by the most suitable for each high pure oxide powder predrying, remove absorption water, Calcination 10h at 1000 DEG C, then by CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃:≥ 99.999%, Al₂O₃: >=99.999% raw material carries out weighing according to mol ratio, dispensing.Raw material is abundant Use isostatic pressing machine briquet after mix homogeneously, be then charged in alumina crucible, put Muffle furnace into Middle sintering, was warming up to 1300 DEG C with 10 hours, and constant temperature was lowered the temperature through 10 hours after 10 hours To room temperature, block is taken out and puts into Iridium Crucible；Use Czochralski grown Ca_0.0015:Yb_0.45Y_2.5485Al₅O₁₂Fast flashing crystal: do insulation material with zirconium oxide and aluminium oxide, Sealing observation panel with gem sheet, seed crystal is the pure YAG seed crystal in<111>direction, and crystal growth is at height Pure Ar atmosphere is carried out.The pull rate of crystal is 0.9mm/h, and rotary speed is 14-30rpm, Controlling the growth of crystal Raised key axis, growth temperature is 1970 DEG C.Crystal growth is through shove charge → evacuation → applying argon gas → temperature increasing for melting materials → roasting crystal seed → sow → necking down → shouldering → isodiametric growth → carry de-and The processes such as cooling, whole growth cycle about 9 days.Grow the colourless of a size of Φ 50*100mm Transparent Ca_0.0015:Yb_0.45Y_2.5485Al₅O₁₂Crystal, crystal weighs about 1200g.

Embodiment 3: Czochralski grown Ca²⁺Doping content is 1at%, Yb³⁺Doping content is 30% Ca_0.03:Yb_0.9Y_2.07Al₅O₁₂Scintillation crystal

First by the most suitable for each high pure oxide powder predrying, remove absorption water, Calcination 10h at 1000 DEG C, then by CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃:≥ 99.999%, Al₂O₃: >=99.999% raw material carries out weighing according to mol ratio, dispensing.Raw material is abundant Use isostatic pressing machine briquet after mix homogeneously, be then charged in alumina crucible, put Muffle furnace into Middle sintering, was warming up to 1300 DEG C with 10 hours, and constant temperature was lowered the temperature through 10 hours after 10 hours To room temperature, block is taken out and puts into Iridium Crucible；Use Czochralski grown Ca_0.03:Yb_0.9Y_2.07Al₅O₁₂Fast flashing crystal: do insulation material with zirconium oxide and aluminium oxide, uses Gem sheet seals observation panel, and seed crystal is the pure YAG seed crystal in<111>direction, and crystal growth is high-purity Ar atmosphere is carried out.The pull rate of crystal is 0.9mm/h, and rotary speed is 14-30rpm, control Combinations body Raised key axis grows, and growth temperature is 1970 DEG C.Crystal growth through shove charge → evacuation → Applying argon gas → temperature increasing for melting materials → roasting crystal seed → sow → necking down → shouldering → isodiametric growth → put forward de-and fall The processes such as temperature, whole growth cycle about 9 days.Grow the colourless of a size of Φ 50*100mm Bright Ca_0.03:Yb_0.9Y_2.07Al₅O₁₂Crystal, crystal weighs about 1200g.

Embodiment 4: descent method for growing Ca²⁺Doping content is 0.01at%, Yb³⁺Doping content is 15% Ca_0.003:Yb_0.45Y_2.547Al₅O₁₂Scintillation crystal

First by the most suitable for each high pure oxide powder predrying, remove absorption water, Calcination 10h at 1000 DEG C, then by CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃:≥ 99.999%, Al₂O₃: >=99.999% raw material carries out weighing according to mol ratio, dispensing.Raw material is abundant Use isostatic pressing machine briquet after mix homogeneously, be then charged in alumina crucible, put Muffle furnace into Middle sintering, was warming up to 1300 DEG C with 10 hours, and constant temperature was lowered the temperature through 10 hours after 10 hours To room temperature, block is taken out and puts into Iridium Crucible；Use descent method for growing Ca_0.003:Yb_0.45Y_2.547Al₅O₁₂Fast flashing crystal, described crucible material use high purity graphite or Tungsten-molybdenum alloy, seed crystal is the pure YAG seed crystal in<111>or<100>direction, and crystal growth is high-purity Carrying out in Ar atmosphere, crucible fall off rate is 0.1～1.5mm/h.Growing the isometrical score of size is The transparent Ca of Φ 80*50mm_0.003:Yb_0.45Y_2.547Al₅O₁₂Crystal, crystal weighs about 1400g.

Embodiment 5: temperature ladder method growth Ca²⁺Doping content is 0.15at%, Yb³⁺Doping content is 15% Ca_0.0045:Yb_0.45Y_2.5455Al₅O₁₂Scintillation crystal

First by the most suitable for each high pure oxide powder predrying, remove absorption water, Calcination 10h at 1000 DEG C, then by CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃:≥ 99.999%, Al₂O₃: >=99.999% raw material carries out weighing according to mol ratio, dispensing.Raw material is abundant Use isostatic pressing machine briquet after mix homogeneously, be then charged in alumina crucible, put Muffle furnace into Middle sintering, was warming up to 1300 DEG C with 10 hours, and constant temperature was lowered the temperature through 10 hours after 10 hours To room temperature, block is taken out and puts into tungsten and molybdenum crucible；Use temperature ladder growth Ca_0.0045:Yb_0.45Y_2.5455Al₅O₁₂Fast flashing crystal, described crucible material use molybdenum or Tungsten-molybdenum alloy, seed crystal is the pure YAG seed crystal in<111>or<100>direction, and crystal growth is high-purity Ar atmosphere is carried out, lowers the temperature with the rate of temperature fall that crystal growth rate is 0.1～100 DEG C/h and grow Crystal.Growing the isometrical score of size is the transparent of Φ 80*50mm Ca_0.0045:Yb_0.45Y_2.5455Al₅O₁₂Crystal, crystal weighs about 1400g.

Claims

1. a calcium ytterbium ion is co-doped with YAG fast flashing crystal, it is characterised in that: molecular formula is Ca_3xYb_3yY_3(1-x-y)Al₅O₁₂, x=0.0001～0.01 in formula, y=0.05～0.3, x are Ca ion Doping, y is the doping of substrate Yb ion, and it is equal that Ca ion and Yb ion enter crystal Replace Y-ion case.

2. the preparation method of the yag crystal that a calcium and ytterbium ion are co-doped with, it is characterised in that The method step is as follows:

1. composition of raw materials:

Use CaO, Yb₂O₃、Y₂O₃And Al₂O₃As initial feed and in molar ratio 3x:3y/2:3 (1-x-y)/2:5/2 carries out dispensing, wherein the span of x, y be respectively x=0.0001～ 0.01, y=0.05～0.3；Raw material uses isostatic pressing machine briquet after being sufficiently mixed uniformly, then fills Enter in alumina crucible, put in Muffle furnace and sinter, be warming up to 1300 DEG C with 10 hours, permanent Temperature was cooled to room temperature through 10 hours after 10 hours, block is taken out and puts into crucible；

2. melt method for growing Ca is used_3xYb_3yY_3(1-x-y)Al₅O₁₂Scintillation crystal: with zirconium oxide and oxygen Change aluminum and do insulation material, seal observation panel with gem sheet, use inert gas shielding, growth temperature Being 1950 DEG C, it is Ca that chemical formula is prepared in growth_3xYb_3yY_3(1-x-y)Al₅O₁₂Crystal.

Ca the most according to claim 2_3xYb_3yY_3(1-x-y)Al₅O₁₂The preparation method of crystal, It is characterized in that, raw materials used purity is: CaO: >=99.99%, Yb₂O₃: >=99.999%, Y₂O₃: >=99.999%, Al₂O₃: >=99.999%.

Ca the most according to claim 2_3xYb_3yY_3(1-x-y)Al₅O₁₂The preparation method of crystal, It is characterized in that, described melt method is czochralski method, and described crucible material uses iraurite, and seed crystal is <111>or the pure YAG seed crystal in<100>direction, crystal growth carries out in high-purity Ar atmosphere, carries Pulling rate degree 0.5～5mm/h, crystal rotation 10～30rpm.

Ca the most according to claim 2_3xYb_3yY_3(1-x-y)Al₅O₁₂The preparation method of crystal, It is characterized in that, described melt method is Bridgman-Stockbarger method, and described crucible material uses high purity graphite Or molybdenum, seed crystal is the pure YAG seed crystal in<111>or<100>direction, and crystal growth is high-purity Carrying out in Ar atmosphere, crucible fall off rate is 0.1～1.5mm/h.

Ca the most according to claim 2_3xYb_3yY_3(1-x-y)Al₅O₁₂The preparation method of crystal, It is characterized in that, described melt method is temperature gradient method, described crucible material use molybdenum or Tungsten-molybdenum alloy, seed crystal is the pure YAG seed crystal in<111>or<100>direction, and crystal growth is high-purity Ar atmosphere is carried out, lowers the temperature with the rate of temperature fall that crystal growth rate is 0.1～100 DEG C/h and grow Crystal.