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Beam Analysis

This section provides documentation for the BeamAnalysis class, which is used to analyze the properties of a particle beam. The class performs beam diagnostics such as bunching, energy, and transverse beam sizes, and saves the analysis results to a file.

BeamAnalysis Class​

The BeamAnalysis class analyzes various properties of a particle beam during a simulation, including the bunching factor, transverse beam sizes (sigma_x, sigma_y), and energy. It uses a curve-fitting method to analyze the longitudinal profile of the beam and computes beam characteristics like bunching and transverse sigma values.

Parameters:​

  • filename (str): The name of the file where the analysis data will be saved.

Attributes:​

  • lambda_mod (float): The modulation wavelength for the analysis. Default is 1e-6.
  • nlambdas (int): The number of modulation wavelengths to include in the analysis (default is 4).
  • p (list): A list of particle momenta corresponding to each analysis step.
  • phi (list): A list of phase values corresponding to each analysis step.
  • s (list): A list of longitudinal positions (s) for each analysis step.
  • energy (list): A list of particle energies for each analysis step.
  • bunching (list): A list of bunching factors for each analysis step.
  • sigma_x (list): A list of standard deviations of the transverse beam size in the x-direction for each analysis step.
  • sigma_y (list): A list of standard deviations of the transverse beam size in the y-direction for each analysis step.

Methods:​

__init__(self, filename)​

Constructor to initialize the BeamAnalysis class. This method accepts the filename where the analysis data will be saved.

apply(self, p_array, dz)​

Applies the beam analysis to the particle array (p_array) over a step size (dz). The method:

  1. Defines a test function to fit to the longitudinal profile of the beam.
  2. Selects a portion of the beam that corresponds to the region defined by lambda_mod and nlambdas.
  3. Performs curve fitting to determine parameters related to the beam's longitudinal profile.
  4. Computes the bunching factor and transverse beam sizes (sigma_x, sigma_y).
  5. Appends the computed values (momentum, phase, bunching, sigma_x, sigma_y, energy) to the corresponding lists.

finalize(self)​

Finalizes the beam analysis by saving the computed data (e.g., momentum, phase, bunching factor, transverse sizes) to a text file (filename).

Summary​

The BeamAnalysis class is used for analyzing and saving data related to the longitudinal and transverse properties of a particle beam. It computes parameters such as bunching factor, transverse beam sizes, and energy, and stores the results in a file for later use. This class is useful for beam diagnostics and optimization in accelerator simulations.

Example Usage​

# Create a BeamAnalysis instance with a specified filename
beam_analysis = BeamAnalysis(filename="beam_analysis_results.txt")

# Apply the beam analysis to a particle array `p_array` over a step size `dz`
beam_analysis.apply(p_array, dz=0.01)

# Finalize and save the analysis results to the file
beam_analysis.finalize()