Methods and apparatus are provided for determining a defibrillation treatment protocol in an external defibrillator using a measurement of elapsed time. The first wall panel is received by the at least one channel when the first wall panel is in a display position and is removed from the at least one channel when the first wall panel is in a storage position. The upper horizontal member terminates at each end with a coupling, while the lower horizontal member terminates without a coupling on either end. A plurality of punch units each include a punch frame and a punch member whose front end is used to punch sheets and rear end of the punch member extends out from the punch frame and is in contact with the pushing member. An electron beam is generated to be incident upon a surface. During the cool-down period, the beam successively scans two rows separated by about half the wafer diameter, and travels back and then forth across the distance between the two rows, while the radiation beam source continuously generates the beam.