Design of a Room-Temperature Surko Trap for Precision Low-Energy Electron Scattering and Lifetime Studies

We present the design of a room-temperature Surko electron trap under construction at TIFR, Mumbai. Adapting positron buffer-gas techniques, the apparatus confines electrons, thermalized (~ 25 meV) via electronic and vibrational excitation of N₂ and CF₄. Monte-Carlo simulations applying positron protocols [1] to optimize electron energy resolution and transport efficiency will be presented. The facility targets gaps in low-energy electron-molecule scattering, such as absolute cross-sections for targets relevant to astrophysical environments. Additionally, high energy resolution enables precision studies of dissociative electron attachment in terms of accurate momentum distribution of fragment anions formed at various electron energies [2]. It is also envisaged to measure the dynamics of sharp resonances in biomolecules like Uracil near zero energy [3]. Furthermore, the trap enables the measurement of metastable anion lifetimes (~ μs), which are difficult to probe in continuous beams due to velocity dispersion. The proposed strategy of leveraging the trap’s pulsed, thermalized extraction to define a precise interaction time (t=0) for determining these lifetimes (~ μs), along with its potential for diverse collision studies, will be discussed.