A novel attempt to develop very short period undulators

We are exploring a novel method to fabricate undulator magnets having a very short period. We have succeeded in producing a 100-mm long magnet plate with 4-mm period length, which gives an undulator field of approximately 7kG at a 'virtual gap' of 1.2mm. A spectrum calculation shows that the quality of the radiation emitted from this magnetic field is satisfactory for the fundamental radiation as compared to the ideal undulator field.