region of the quadrupole. Lines go from positive to negative poles. (b) Given your sketch, where is the electric field the strongest? Where is it the weakest? Strongest at any pole, weakest at center. (c) Now imagine that a beam of moving electrons enters the quadrupole, with velocity parallel to the charged rods. When the beam enters the device, its cross-sectional profile is circular. What will the beam look like when it exits the quadrupole on the other side? (Assume that the force exerted on the electrons is not too large.) The beam of electrons would be attened into a oval that is long in the x-axis and short in the y-axis. y ' eam of electrons ~31 O heading info page