A security system is described which controls the access of applications to system resources in the field of interactive multimedia. In one embodiment, a magnetic head tester employs the VCM actuator and the control circuit of a production HDD and has a lightweight, simple HGA fixing mechanism mounted on an actuator arm. Capacity for supporting multiple access can be increased by effectively utilizing limited wireless communication resources. The first ion reflector is disposed at the exit of the drift region to reflect, back towards the entrance, ions which are traveling towards the reflector in the drift region.