| 摘要 |
The invention concerns a method for preparing a polycrystalhne hahde block, of formula ALnX, wherein Ln represents one or more rare earth(s), X represents one or more halogen atom(s) selected among Cl, Br or I and A represents one or more alkali(s) such as K, Li, Na, Rb or Cs, e may be nil, being not more than 3f and f being not less than 1, with low water and oxyhalide content Said method comprises the following steps heating a mixture of at least one compound containing at least one Ln-X bond and a sufficient amount of NH^X to obtain the desired oxyhalide content, said step resulting in a melt including the rare earth hahde, said heating step being followed by a cooling step, the heating step, after reaching 300°С never falling below 200°С before the melt is obtained The resulting blocks enable growth of very pure single crystals with remarkable scintillating properties. |
