Suppression of Emittance Growth Using a Shaped Cold Atom Electron and Ion Source

Abstract

We demonstrate precise control of charged particle bunch shape with a cold atom electron and ion source to create bunches with linear and, therefore, reversible Coulomb expansion. Using ultracold charged particles enables detailed observation of space-charge effects without loss of information from thermal diffusion, unambiguously demonstrating that shaping in three dimensions can result in a marked reduction of Coulomb-driven emittance growth. We show that the emittance growth suppression is accompanied by an increase in bunch focusability and brightness, improvements necessary for the development of sources capable of coherent single-shot ultrafast electron diffraction of noncrystalline objects, with applications ranging from femtosecond chemistry to materials science and rational drug design.

Ionization spectra of highly Stark-shifted rubidium Rydberg states

“…A complete study of these possible Fano resonances may yield a more accurate prediction of the spectrum, but is beyond the scope of this work. 15 15 Results from the numerical calculations for η = 2 · 10 5 . The detuning is given relative to the unperturbed state.…”

“…Furthermore, this opens up the possibility to tune a coupling between ionizing and non-ionizing states by the external electric field. This way of tailoring the ionization process is highly useful for the design of sources of cold ions and electrons for microscopy purposes [13][14][15][16]. Moreover, a precise knowledge of these ionization spectra opens new perspectives for experiments incorporating Rydberg atoms near surfaces, where static electric fields arise due to adsorbates [17][18][19][20].…”

Tipping solutions: emerging 3D nano-fabrication/ -imaging technologies

“…Such possibilities to create strongly directional electron bunches via strong E-fields using ultracold atoms is a rapidly evolving field [40].…”

Recent Advances in Ultrafast Structural Techniques

“…For instance, laser plasma electron accelerators [267][268][269][270][271][272][273] are quickly improving through the reduction of the large energy spread that has limited their application as FED sources. Another interesting candidate is the cold-atom electron source, [202,[274][275][276][277][278][279][280][281] which has recently been proposed as an alternative to photoinjectors owing to the large reduction in electron beam emittance that should considerably improve the X-ray beam properties. Moreover, important advances have been made in the development and implementation of dynamic and ultrafast electron microscopes [3,[282][283][284][285][286][287][288][289].…”