Characterization study of a hybrid undulator

In this paper, we describe the design details of a prototype DEVU25.20h, a 9 mm minimum gap, hybrid undulator designed, built, and measured in house at the IDD Laboratory, DAVV, Indore, India. The undulator is a NdFeB-based hybrid undulator with 25 period and 20 mm each period length. Low-cost M35 grade cobalt steel is used as the pole material of the undulator. The magnet size is 6.25 mm in width, 6.25 mm in height, and 50 mm in length. The pole size is 3.75 mm in width, 4.7 mm in height, and 50 mm in length. The gap is manually driven. The 20 periods are arranged in 112 mm wide and 500 mm long 316 steel jaws. The two jaws are held in a rigid variable gap support structure giving a minimum gap of 9 mm. The hybrid undulator is designed as asymmetric structure, i.e., one end starts with a magnet and terminates with a pole at the other end. The measured performance and characteristics of the undulator are evaluated with RADIA.