Single particle detection system for strong-field QED experiments

Abstract

Measuring signatures of strong-field quantum electrodynamics (SF-QED) processes in an intense laser field is an experimental challenge: it requires detectors to be highly sensitive to single electrons and positrons in the presence of the typically very strong x-ray and γ-photon background levels. In this paper, we describe a particle detector capable of diagnosing single leptons from SF-QED interactions and discuss the background level simulations for the upcoming Experiment-320 at FACET-II (SLAC National Accelerator Laboratory). The single particle detection system described here combines pixelated scintillation LYSO screens and a Cherenkov calorimeter. We detail the performance of the system using simulations and a calibration of the Cherenkov detector at the ELBE accelerator. Single 3 GeV leptons are expected to produce approximately 537 detectable photons in a single calorimeter channel. This signal is compared to Monte-Carlo simulations of the experiment. A signal-to-noise ratio of 18 in a single Cherenkov calorimeter detector is expected and a spectral resolution of 2% is achieved using the pixelated LYSO screens.

Advances in QED with intense background fields

“…. 12, 0.0036) [64]; DRACO (0.6, 0.0027 [230 MeV]) [65]; E144 (0.36, 0.83) [66]; E320 (2, 0.15) [39]; E320 II (proposed upgrade) (16, 0.15) [67]; ELI [45]; EP-OPAL [68]; Gemini 1 (1 . .…”

“…1 for some estimate of the increase in papers published in recent years. QED in intense fields has also begun to attract attention from the high energy physics community, and experiments colliding conventionally-accelerated electron beams with intense laser pulses will be performed in E320 [39] at SLAC and LUXE [40,41,42,43] at DESY in the near future. At the same time, a new generation of laser facilities have recently come online (CoRELS [44]), are being commissioned (ELI [45]), are being built (SEL [46]) or are in the process of consultation (MP3 [47]).…”

Fully polarized nonlinear Breit-Wheeler pair production in pulsed plane waves

“…In this work, we are interested in the spin properties of each produced particle, but not the spin correlation between the paired particles. This consideration is for the generation of a polarized particle source, and partially because of the difficulty in the coherent measurement for the spin state of the paired particles [53]. To manifest the polarization properties of the produced positron ρ + (electron ρ − ), one can trace the matrix ρ f over the spin states of its paired electron (positron), as…”

“…The decay of a high-energy photon into a pair of electron and positron when colliding with intense laser pulses, is often referred to as the nonlinear Breit-Wheeler (NBW) pair production [1][2][3], and has been measured in the perturbative regime via the landmark E144 experiment more than two decades ago [4,5]. The measurement of the process in the transition regime from the perturbative to the non-perturbative regime is one of the main goals for the modern-day laser-particle experiments [6][7][8][9][10][11]. For the next generation of multi-PW laser facilities [12][13][14], the NBW pair production will be explored in the thoroughly non-perturbative regime.…”

“…The study of the photon polarization effect on the NBW pair production and the spin polarization property of the produced particles is partly motivated by the upcoming high-energy laser-particle experiment, i.e., LUXE at DESY [6][7][8] and E320 at SLAC [9][10][11] in which photons with energy O(10 GeV) are planned to be generated to collide with laser pulses with the intermediate intensity ξ ∼ O (1), where ξ is the classical nonlinearity parameter. Compact expressions of the positron (electron) spectrum and spin polarization depending on the seed photon polarization are derived starting from the theory of scattering matrix and polarization density matrix.…”