It is a key performance requirement for a double-crystal monochromator that the exit is fixed

and in order to improve the height accuracy of the exit in T-shaped exit fixed mechanism

the expression between the height of the exit and various original errors was put forward using geometrical analysis method.According to the independent action principle of original errors

accuracy synthesis of T-shaped exit fixed mechanism was studied by using the equal accuracy method

and the tolerance ranges of original errors were obtained.How to calculate the tolerance ranges of original errors was explained by giving an example.