Double-bend achromat
= Double-bend achromat
A lattice cell with two bending magnets whose dispersion and dispersion slope vanish at its boundaries. In an ideal identical-uniform-bend model with horizontal damping partition one, its minimum <geometric emittance> is $C_q\gamma^2\theta^3/(4\sqrt{15})$, larger than the unconstrained theoretical minimum because of the achromatic <Boundary condition>[boundary conditions].