A new technique of beam energy resolution by using only quadrupole magnets

摘要

In the standard technique of beam energy resolution one uses the property of momentum dispersion by dipole magnets. It is shown that one can, alternatively, use three quadrupole magnets to select the beam momentum or energy. The lengths and magnetic fields of the quadrupoles can be adjusted to focus the particles of the required energy and simultaneously defocus the particles of higher or lower energies. For obtaining a very high resolving power one can use such triplets in cascade. The resolving powers of these are multiplicative, whereas in the case of dipoles one can use just two bending magnets for roughly doubling the resolving power. This method is different from the technique used in quadrupole mass filters where RF field is used in quadrupoles. [References: 18]