Magnetic Spectroscopy with Scintillation Detectors at the LUXE Experiment
The success of the physical model of quantum electrodynamics relies on the use of a small perturbation above a quantum vacuum solution. In the physically possible case of a strong electric field, defined as being near or greater than the Schwinger limit, the assumption underlying this perturbation theory approach becomes unviable. In this new regime lies unexplored phenomena and a chance at new physics.
The upcoming LUXE experiment at the Deutsches ElektronenSynchrotron intends to reach new parameter-space for intensity of an electric field, and access the strong regime. This is performed in two modes, with a modern high-power laser firing intense pulses at either accelerated bunches of electrons from the EU.XFEL (e-laser mode), or high-energy photons produced from the same EU.XFEL electron bunches (γ-laser mode). This thesis includes analysis of high-energy Bremsstrahlung emission, with the goal of accurately describing the flux of high-energy photons within the interaction point at LUXE.
Presented here is the design and performance of operation of a magnetic spectrometer system, used to reconstruct the energy distributions of a flux of electrons, using a screen of scintillating material and optical cameras. This includes results from both simulation and using a prototype within test-beam.
The Bremsstrahlung-related test-beam measurement resulted in a reconstructed polar angle profile which gives a reduction of maximum photon flux of 63% compared to the accepted model, if one assumes all measured discrepancy is due to inaccuracy in the theory.
The suitability of the scintillator screen & camera system for LUXE is proven, in particular as the reconstruction of energy to ± 2% on a single-shot-basis is shown in simulation. The signal to noise ratio and dynamic range of the system, measured in test-beam, were included in the simulation.
https://discovery.ucl.ac.uk/id/eprint/10180560/7/john_andrew_hallford_thesis_corrected_redacted.pdf