Question

You are helping to design a piece of equipment that will aim beta particles (electrons) from a radioactive source at cancerous tumors in patients. You wonder whether it would be more efficient to use a uniform electric or uniform magnetic field to aim the electrons and decide to calculate the magnitude of the fields needed in the two cases. The electrons will emerge from the source with a kinetic energy of 2.5 keV (kiloelectronVolts) and your apparatus needs to deflect their velocities by an angle of up to 5°. Space constraints dictate that the length of the region with the uniform field through which the particles travel can be no longer than 40 cm. You will also need to specify the best orientation for the fields relative to the direction in which the electrons are initially traveling.

Answer 1