Linac Alignment Algorithm: Analysis on 1-to-1 Steering

Sun, Yipeng ; Adolphsen, Chris ; /SLAC

关键词: ACCELERATION;    ACCELERATORS;    ALGORITHMS;    ALIGNMENT;    BEAM EMITTANCE;    BEAM POSITION;    BETATRON OSCILLATIONS;    CAVITIES;    FOCUSING;    LINEAR ACCELERATORS;    LINEAR COLLIDERS;    MAGNETS;    MONITORS;    QUADRUPOLES;    SIMULATION Accelerators;    ACCPHY;   

DOI  :  10.2172/1022483
RP-ID  :  SLAC-PUB-14322
PID  :  OSTI ID: 1022483
Others  :  TRN: US1104380

学科分类：核物理和高能物理

美国|英语

来源: SciTech Connect

【 摘 要 】

In a linear accelerator, it is important to achieve a good alignment between all of its components (such as quadrupoles, RF cavities, beam position monitors et al.), in order to better preserve the beam quality during acceleration. After the survey of the main linac components, there are several beam-based alignment (BBA) techniques to be applied, to further optimize the beam trajectory and calculate the corresponding steering magnets strength. Among these techniques the most simple and straightforward one is the one-to-one (1-to-1) steering technique, which steers the beam from quad center to center, and removes the betatron oscillation from quad focusing. For a future linear collider such as the International Linear Collider (ILC), the initial beam emittance is very small in the vertical plane (flat beam with {gamma}{epsilon}{sub y} = 20-40nm), which means the alignment requirement is very tight. In this note, we evaluate the emittance growth with one-to-one correction algorithm employed, both analytically and numerically. Then the ILC main linac accelerator is taken as an example to compare the vertical emittance growth after 1-to-1 steering, both from analytical formulae and multi-particle tracking simulation. It is demonstrated that the estimated emittance growth from the derived formulae agrees well with the results from numerical simulation, with and without acceleration, respectively.