METHOD OF OBTAINING SCINTILLATION MONOCRYSTALS BASED ON LANTHANUM BROMIDE Russian patent published in 2015 - IPC C30B11/00 C30B29/12 C09K11/85 G01T1/202 

FIELD: chemistry.

SUBSTANCE: invention can be applied in the production of sensitive elements of a gamma- and roentgen radiation detector. Scintillation monocrystals La_(1-m-n)Hf_nCe_mBr_(3+n), where m is the molar part of La substitution with cerium (0.0005≤m≤0.3), n is the molar part of La substitution with hafnium (0≤n≤0.015), are obtained from a mixture of metal bromides. The charge is loaded in a quartz ampoule with inoculum, the ampoule is vacuumised, soldered, placed in a growth installation, heated to the charge melting, exposed until an equilibrium condition is set in the liquor, a monocrystal is grown by the creation of a gradient temperature section in the ampoule and cooled, with the application of a multi-zone growth installation with the electrodynamic movement of a temperature gradient in the longitudinal-axial direction. To melt the charge the temperature of the installation heater in the zone of the inoculum t₁ is selected from the interval of 685°C<t₁<720°C, the temperature of the following heater t₂ - from the interval of 770°C≤t₂≤790°C. After the charge melting the ampoule is exposed for not less than 10 hours, the monocrystal growing is realised by the movement of the temperature gradient along the longitudinal axis of the installation at a rate of 0.3 mm/h≤v_tg≤0.5 mm/h. Boundary values of temperatures of so-called cold t_cz and hot t_hz zones of the gradient section are selected from the intervals of 720°C<t_cz≤740°C and 790°C≤t_hz≤820°C, with the ampoule cooling being realised at a rate of not higher than 15°C/h.

EFFECT: accuracy of supporting temperature fields, stability of their movement at all stages of the crystal growth, strict control of temperature and time parameters of the growth process, obtaining monocrystals with specified optical characteristics and sizes with high output.

2 cl, 2 tbl, 9 ex