Design of a revolving helical staggered undulator

This investigation proposes a revolving helical staggered undulator with 10-mm and 15-mm period lengths for free electron laser operation. The helical staggered structure with a 10-mm period length is designed to produce vertical and horizontal field strength of 0.625 T at a phase shift of 90 degrees, by driving a longitudinal solenoid field of 0.7 T with a 3-mm gap. Three-dimensional magnetic field analysis was performed using RADIA computer code. An optimized magnetic structure was studied over various operating field ranges. A revolving helical undulator is equipped with two helical magnetic arrays to switch the helicity of radiation and broad radiation spectrum. Accordingly, the design of a helical staggered undulator is outlined.