A high resolution, broad energy acceptance spectrometer for laser wakefield acceleration experiments.

Area of Science:

• Plasma Physics
• Particle Accelerators
• High-Energy Physics

Background:

• Laser wakefield acceleration produces high-energy electron beams with broad energy ranges and significant divergence.
• Accurate measurement of electron energy spectra is crucial for understanding and optimizing laser wakefield acceleration.
• Existing spectrometers face challenges with beam divergence, pointing jitter, and limited energy resolution.

Purpose of the Study:

• To design and characterize a new electron energy spectrometer tailored for laser wakefield experiments.
• To achieve high energy resolution and accuracy over a broad energy spectrum.
• To overcome the limitations of beam divergence and pointing jitter in measurements.

Main Methods:

• A two-magnet spectrometer design utilizing permanent magnets and an optional electromagnet.
• Electron refocusing in the energy plane to enhance resolution without postprocessing.
• Dual detection systems: calibrated scintillation screens and a scintillating fiber array with a CCD.

Main Results:

• Spectrometer acceptance range of 2.5-400 MeV (E(max)/E(min)>100).
• Achieved energy resolution better than 1% rms for electron energies above 25 MeV.
• Demonstrated high accuracy and reliability without image deconvolution.

Conclusions:

• The developed spectrometer effectively measures electron energies from laser wakefield experiments with unprecedented resolution.
• The design addresses key challenges, enabling more precise characterization of accelerated electron beams.
• This instrument advances the study and application of laser-driven particle acceleration.