Impedance Scaling for Small-angle Tapers and Collimators

Stupakov, G. ; /SLAC

关键词: COLLIMATORS;    IMPEDANCE;    SCALARS;    MAXWELL EQUATIONS;    FREQUENCY RANGE Accelerators;    ACCPHY;    XFEL;   

DOI  :  10.2172/972231
RP-ID  :  SLAC-TN-10-001
PID  :  OSTI ID: 972231
Others  :  TRN: US201005%%190

美国|英语

来源: SciTech Connect

【 摘 要 】

In this note I will prove that the impedance calculated for a small-angle collimator or taper, of arbitrary 3D profile, has a scaling property that can greatly simplify numerical calculations. This proof is based on the parabolic equation approach to solving Maxwell's equation developed in Refs. [1, 2]. We start from the parabolic equation formulated in [3]. As discussed in [1], in general case this equation is valid for frequencies {omega} >> c/a where a is a characteristic dimension of the obstacle. However, for small-angle tapers and collimators, the region of validity of this equation extends toward smaller frequencies and includes {omega} {approx} c/a.