2024 Workshop on Polarized Sources, Targets, and Polarimetry

Session

Polarized Electron Sources III

Sep 26, 2024, 4:00 PM

Cebaf Center Auditorium (Jefferson Lab)

Conveners

Polarized Electron Sources III

• Marcy Stutzman (Jefferson Lab)

93. Development of GaN as a Robust Spin-Polarized Photocathode at Cornell University

Samuel Levenson

9/26/24, 4:00 PM

The creation of a durable spin-polarized electron source that can maintain mA-scale average beam currents over an extended period in a photoinjector is essential for the success of future accelerator facilities like the International Linear Collider (ILC). In the Bright Beams Laboratory at Cornell University, photoemission of a spin-polarized electron beam from gallium nitride (GaN)...

35. High-Precision Measurements of Asymmetry and Quantum Efficiency in Photocathodes for Polarised Electron Beam Experiments

Jennifer Trieb (Johannes Gutenberg-Universität)

9/26/24, 4:20 PM

At the new, energy-recovering superconducting accelerator MESA in Mainz, spin-polarised electrons are required in the P2 experiment. Here the requirements increase considerably compared to the experiments at the micotron MAMI in Mainz.

A very sensitive part of the photocathodes lies in the specially prepared surface, characterised by its negative electron affinity. This surface is highly...

55. Enhanced durability NEA surface layer for GaAs photocathodes using Cs, O$_2$, and Li* (via Zoom)

Dr Maximilian Herbert (Institut für Kernphysik, Technische Universität Darmstadt)

9/26/24, 4:40 PM

Photocathodes based on GaAs are used as photo-electron sources to supply spin-polarized, high-current electron beams for accelerator applications. A thin surface layer, typically comprised of Cs and an oxidant, needs to be applied to such photocathodes during an activation process in order achieve negative electron affinity (NEA). The NEA layer and the associated quantum efficiency (QE)...

97. Quantum Efficiency, Electron Spin Polarization and Lifetime Study for GaAs Based Truncated Nanocone Array Photocathodes

Md Aziz Ar Rahman (Old Dominion University)

9/26/24, 5:00 PM

GaAs based nanostructured photocathodes with truncated nano-cones were fabricated and studied at a low voltage test chamber. Quantum Efficiency (QE) enhancement due to dipole resonance mode excitation has been consistently observed throughout the waveband of 530-680 nm compared to the QE of flat bulk GaAs wafers. A modified photocathode activation recipe was followed for negative electron...