Magnet lattice for the Siam Photon Source

The magnet lattice for the Siam Photon Source, the first storage ring for synchrotron radiation research in Thailand, has been designed. The storage ring has a double-bend achromat lattice and fourfold symmetry with four straight sections. Although the magnet lattice is relaxed, an emittance value of 72 π nm rad has been obtained, which is only 1.4 times as large as the theoretical minimum emittance with eight bending magnets. The dynamic aperture is found to be much larger than the physical aperture.