Determination of the Level Error with the Electric-Collimator of the LLMC

In this paper, we introduce the principle of the electric-collimator which is used in the LLMC and discuss the method of determining the scale of the Reticon and its precision when the electric-collimator is used to determine the level error of the up-plate of the location plate. Then, the method of determining the tilt of the slit used in the electric-collimator is discussed. Finally, the range of the level error and its measuring accuracy are given, showing that for the LLMC, the axis system is not needed to be too strict, but the accuracy of the determinantion of the level error is needed to be very high.