PX156 - K3 - cyclotron

to accelerate heavy things (eg: protons, ions) in not much space
essentially a rolled up linear accelerator

hollow conducting structures known as 'Dees' connected to an AC source
the electric field in the gap changes direction as the AC power supply
particle accelerates across the gap under the application of an electric field
moves in a half circle in the Dee under the application of a magnetic field
moves faster in subsequent half-orbit
key: time taken to travel each half orbit is the same: 'equal time assumption
time in Dee:

\begin{aligned} t & = \frac{d}{v} \\ = \frac{π}{v} r \\ = \frac{π}{v} \cdot \frac{m v}{q B} \\ ∴ t & = \frac{π m}{q B} \end{aligned}

advantages

cheap
small footprint
can accelerate relatively heavy particles

drawbacks

relies on the 'equal time assumption'
- fine at low-medium energies $\sim 100 M e V$
- relativistic speeds are difficult to accelerate to