Reconstruction of electron beam distribution using phase-retrieval algorithm

Area of Science:

• Coherent electron optics
• Image reconstruction techniques
• Particle beam diagnostics

Background:

• Reconstructing light source shapes, like electron beams, relies on inverse Fourier transformation of spatial coherency.
• Young's interferometer is a key instrument for measuring the complex degree of spatial coherency.
• Phase measurement errors can limit the accuracy of shape reconstruction.

Purpose of the Study:

• To numerically investigate the application of a phase-retrieval algorithm for reducing phase errors in spatial coherency measurements.
• To improve the accuracy of electron beam shape reconstruction using this advanced algorithm.
• To demonstrate the practical utility of the phase-retrieval method with experimental data.

Main Methods:

• Numerical simulation of electron beam propagation and spatial coherency measurement.
• Application of a phase-retrieval algorithm to simulated and experimental complex degree of spatial coherency data.
• Utilizing Young's interferometer principles for data acquisition.

Main Results:

• The phase-retrieval algorithm effectively reduced phase measurement errors in the complex degree of spatial coherency.
• Accurate reconstruction of an asymmetric electron beam's shape was achieved.
• Successful validation of the numerical findings with experimental data from the Pohang Accelerator Laboratory.

Conclusions:

• Phase-retrieval algorithms are a viable method for enhancing the accuracy of electron beam shape reconstruction.
• This technique offers improved diagnostics for particle beams, particularly those with complex or asymmetric profiles.
• The study validates the algorithm's effectiveness in both simulated and real-world experimental conditions.