A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. According to one method, presence information is collected for a presentity. When the knob is turned, a tightness of the bushing ring against the flared round recess is progressively changed to thereby adjust the tape holder to different degrees of immobility, allowing the tape dispenser to apply to tapes of different adhesion ability. The local computer system which received the password sends the password to the remote computer system for personal identification of the user. The advantages include efficient productivity, excellent magnetic performance, a minimal or zero amount of Tb or Dy used, an increased coercive force, and a minimized decline of remanence.