Question

Accelerated electron beams are often used to study features of atoms on the surfaces of materials. If you wanted to alter the design of an electron accelerator to produce an electron beam appropriate for the studying the nuclei of atoms instead, what would be the appropriate alteration?

Answer 1

Solution

In the case of a linear accelerator like particle accelerator, the accelerating potential must be increased. In the case of cyclotron like accelerators, the radius of ' D ' s must be increased.

The modifications done to the accelerator must be for producing even more energetic ( more accelerated ) electrons. In order to produce more acceleration to charged particle like electron, the accelerating potential must be increased. Electron beams used to study material surface morphology ( in SEM etc ) are less energetic than those required to study the nucleus. The matter waves associated with electrons is used in both. Higher the momenta of electron ( higher energy) lower will be the wavelength of associated matter wave . Since diffraction, interference like wave phenomenons are more pronouncing when the incident wavelength is comparable with obstacle sizes it is interacting with. Nuclear size is of the order of Armstrongs(10^-10) and hence they require much shorter electron waves to produce diffraction effects. Hence electron beams must be enegetic while studying nucleus of atoms. Thus the accelerators must be modified to have higher accelerating potentials.