T型高差固定结构中双晶长度最小定位算法

设计双晶单色仪时,为减小T型高差固定结构中双晶长度,提出了一晶长度最小定理与二晶长度最小定理。这两个定理中,前者表明入射光只有掠过转角仪中心O点,一晶长度可取为最小值;后者表明出射光只有掠过两个滑道的交点P,二晶长度可取为最小值。双晶长度最小定位算法使这两个双晶定位条件同时满足,从而使一晶与二晶长度同时最小。结合入射光高度放大法,将此定位算法应用于EXAFS双晶单色仪中,可使双晶长度分别由80mm,180mm都减小到60mm。

A method of location of shortest double-crystals in T-shaped exit fixed mechanism

When designing a double-crystal monochromator, in order to shorten the length of double crystals in T-shaped exit fixed mechanism, theorems of the shortest first crystal and that of the shortest second crystal are put forward. The former one indicates only when the entrance beam sweeps point O, the center of the goniometer, can the first crystal be shortened to the minimum; the later one indicates only when the exit beam sweeps point P, the crossing point of two slide tracks, can the second crystal be shortened to the minimum. The locating method of double crystals meets two location conditions of double crystals at the same time, so the double crystals are both shortened to their minimum. In combination with the enlargement of the aspect of entrance beam, this locating method can be applied to designing the double-crystal monochromator for EXAFS, both crystals have been shortened to 60mm from 80mm and 180mm respectively.