Speaker
Description
The stretched wire method is one of the magnet alignment techniques and also the field measurement techniques, especially for long and narrow magnets. A stretched wire measurement system has been developed at IHEP to measure the roll angles of the longitudinal gradient dipole and quadrupole magnets, as well as two superconducting combined quadrupole magnets in the horizontal test. The wire position is detected by an absolute scanner AS1 with a Leica AT960 laser tracker or a coordinate measuring machine. Some experiments are performed with a CMM for verification. The linear motion and the circular trajectory are compared. The roll angle is obtained by linear fitting of linear motion or Fourier analysis of the circular trajectory. The roll angle measurement accuracy obtained is better than 30 urad.
