PbWO_(4) crystal is a dense,fast and radiation hard scintillator which is being t ested to be used as a radiator of EM calorimeters.With a density of 8.2g/cm^(3),t his crystal is having a decay time of less than 10nm ...PbWO_(4) crystal is a dense,fast and radiation hard scintillator which is being t ested to be used as a radiator of EM calorimeters.With a density of 8.2g/cm^(3),t his crystal is having a decay time of less than 10nm for about 85% of light outp ut.Its unit radiation length, x_(0) is shorter than any of the well establish ed scintillators. In order to improve the scintillating property,CeO_(2)(0.01wt%) and Ge_(2)O_(3) add ed into PWO,Ce:Ge:PWO crystal was grown by Czochraski method.The growth technolo gy parameters were:the temperature gradient of 40℃/cm,the rotating rate of 30r/ m in and the growth speed of 1 2mm/h.The transmissibility of pure PWO crystal was 68%,where as that of Ce:Ge:PWO was 70%.The light yield of pure PWO and Ce:Ge:PWO was 9.5p.e./MeV and 14.6 p.e./MeV,respectively.展开更多
KDP and its deuterated analog DKDP (K (D x H 1- x ) 2PO 4) are the first ch oice materials in the fabrication of optical switcher and frequency converter fo r inertial confinement fusion study.In the past years,the gr...KDP and its deuterated analog DKDP (K (D x H 1- x ) 2PO 4) are the first ch oice materials in the fabrication of optical switcher and frequency converter fo r inertial confinement fusion study.In the past years,the growth technique has b een d eveloped greatly.Large aperture crystals can be grown with various methods,such as,temperature decreasing,solution circular flow,and rapid growth method,which i ntend to reduce the cost of production and satisfy the requirement of ICF.As to rapid growth method,much attention has been paid to solution stability and the K DP crystal qualities of this method which has been proved that high speed can be obtained.LLNL has grown KDP crystal with dimension of 57mm×57mm×55mm,260 kil ogram in 59 days.This method is very different from conventional method for grow ing KDP crystal in three directions uniformly.In addition to the growth of the pyramidal faces,rapid crystallization from supersaturated solution results in si gnificant growth of prismatic faces.Inclusions of growth solution and incorporat ion of metal impurities will occur in the prism sector as prism extends very muc h by this method.Fast growth needs high supersaturation(10%—30%),so the grow th condition,such as ,raw materials,apparatus,temperature lowing proceed should be controlled very strictly.In order to improve the utilization of KDP crystal g rown by point seed method,we developed 4 vessels circular technique on the bas e of 3 vessels circular technique recently.展开更多
文摘PbWO_(4) crystal is a dense,fast and radiation hard scintillator which is being t ested to be used as a radiator of EM calorimeters.With a density of 8.2g/cm^(3),t his crystal is having a decay time of less than 10nm for about 85% of light outp ut.Its unit radiation length, x_(0) is shorter than any of the well establish ed scintillators. In order to improve the scintillating property,CeO_(2)(0.01wt%) and Ge_(2)O_(3) add ed into PWO,Ce:Ge:PWO crystal was grown by Czochraski method.The growth technolo gy parameters were:the temperature gradient of 40℃/cm,the rotating rate of 30r/ m in and the growth speed of 1 2mm/h.The transmissibility of pure PWO crystal was 68%,where as that of Ce:Ge:PWO was 70%.The light yield of pure PWO and Ce:Ge:PWO was 9.5p.e./MeV and 14.6 p.e./MeV,respectively.
文摘KDP and its deuterated analog DKDP (K (D x H 1- x ) 2PO 4) are the first ch oice materials in the fabrication of optical switcher and frequency converter fo r inertial confinement fusion study.In the past years,the growth technique has b een d eveloped greatly.Large aperture crystals can be grown with various methods,such as,temperature decreasing,solution circular flow,and rapid growth method,which i ntend to reduce the cost of production and satisfy the requirement of ICF.As to rapid growth method,much attention has been paid to solution stability and the K DP crystal qualities of this method which has been proved that high speed can be obtained.LLNL has grown KDP crystal with dimension of 57mm×57mm×55mm,260 kil ogram in 59 days.This method is very different from conventional method for grow ing KDP crystal in three directions uniformly.In addition to the growth of the pyramidal faces,rapid crystallization from supersaturated solution results in si gnificant growth of prismatic faces.Inclusions of growth solution and incorporat ion of metal impurities will occur in the prism sector as prism extends very muc h by this method.Fast growth needs high supersaturation(10%—30%),so the grow th condition,such as ,raw materials,apparatus,temperature lowing proceed should be controlled very strictly.In order to improve the utilization of KDP crystal g rown by point seed method,we developed 4 vessels circular technique on the bas e of 3 vessels circular technique recently.
