Method and device for diagnosing bundle length

Abstract

The invention discloses a beam bunch length diagnosis method and device. At present, a subpicosecond-level electron beam widely adopts a cylindrical or multi-cavity structure. By contrast, the beam bunch length diagnosis method provided by the invention adopts a rectangular single-deflection cavity to work in a TM120 mode or TE102 mode, and a vertical direction deflection effect is generated on anelectron beam through a horizontal magnetic field on a central axis. Due to nonaxisymmetry of a cross section of a cavity, mode separation can be naturally realized while a length-width ratio is guaranteed not to be 1, and an asymmetric structure does not need to be additionally introduced, so that a cavity design process is greatly simplified. Resonant frequency in a single-cavity TM120 mode orTE102 mode has nothing to do with the longitudinal size of the cavity, a pi phase shift mode under a multi-cavity structure can be abandoned, and optimization can be performed aiming at a transverse size and a longitudinal size separately, thereby obtaining a relatively compact structure. The beam bunch length diagnosis method and device go through three-dimensional electromagnetic calculation andbeam tracking verification, are novel in concept and reliable in design, and are of great significance to diagnosis of an ultrafast electron beam represented by free electron laser application.

Description

technical field [0001] The invention belongs to the field of nuclear science and technology, and more specifically relates to a method and device for diagnosing bundle length. Background technique [0002] In recent years, accelerator-based light source devices, such as free electron lasers and synchrotron radiation light sources, have been widely used in life sciences and materials science because of their excellent performance that traditional light sources cannot match, such as ultra-high brightness, ultra-short pulse, and strong coherence. A great success has been achieved in the field of atomic and molecular dynamic detection. Correspondingly, with the application of photocathode electron guns and magnetic compression systems, the length of the electron beams produced by the accelerator has been shortened from the initial nanosecond level to the picosecond or even femtosecond level, which brings great advantages to the measurement of the longitudinal distribution of the...

AI Technical Summary

Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a bunch length diagnostic method and device, thereby solving the difficulty in separating the modes of the cylindrical deflection cavity in the current ultrafast electron beam detection and the need for a specially designed asymmetric structure And cavity design analysis complex technical issues

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