Cyclotron Frequency Bandwidth and Energy-Time Uncertainty

4 Cyclotron Frequency Bandwidth and Energy-Time Uncertainty 

Although discouraging for ion detection, the energy-time uncertainty principle opens up new perspectives for ion excitation. According to Av x At 1, a rectangular pulse of 1 ms duration covers a frequency bandwidth of 1000 Hz a pulse of even 1 ps should correspond to a bandwidth (frequency uncertainty) of 1 MHz, i.e., shorter pulses cover increasingly broader ranges. This has been employed in so-called pulse excitation. 

Note The bell model To understand pulse excitation, it is helpful to consider a mechanical comparison - a bell, for exanple, does not require excitation at its resonance frequency. Instead, a short strike with a hammer (pulse excitation) is hilly sufficient. The bell takes up the energy with no specified frequency (all potential frequencies are contained) and automatically finds its own frequency plus its overtones to resonate and, thus, to sound. 

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