Beijing Q3D magnetic spectrometer and its applications

The Beijing Q3D magnetic spectrometer has been used for many experiments in this laboratory. It is found that the locations of the effective field boundaries (EFB) of the dipole magnets with the floating snakes are shifted towards the magnets, comparing with the design. Their effects on the ion-optical performances of the spectrometer were checked by the calculation with the program RAYTRACE and a method to reoptimize the performance with the program is described. The experimental investigation of the spectrometer performances has been carried out by the so-called ''experimental ray-tracing'' method. A method to adjust experimentally the focal plane angle in a finite region is proposed. The focal plane angle of 47.5 has been adjusted successfully to the original designed value, 45 . By the use of this method not only the various features of the spectrometer are well determined, but also the empirical field-setting for every adjustable magnetic element is uniquely set up. Some of the applications are mentioned in this paper. (orig.)