Formation of Compressed Flat Electron Beams with High Transverse-Emittance Ratios

Flat beams -- beams with asymmetric transverse emittances -- have important applications in novel light-source concepts, advanced-acceleration schemes and could possibly alleviate the need for damping rings in lepton colliders. Over the last decade, a flat-beam-generation technique based on the conversion of an angular-momentum-dominated beam was proposed and experimentally tested. In this paper we explore the production of compressed flat beams. We especially investigate and optimize the flat-beam transformation for beams with substantial fractional energy spread. We use as a simulation example the photoinjector of the Fermilab's Advanced Superconducting Test Accelerator (ASTA). The optimizations of the flat beam generation and compression at ASTA were done via start-to-end numerical simulations for bunch charges of 3.2 nC, 1.0 nC and 20 pC at ~37 MeV. The optimized emittances of flat beams with different bunch charges were found to be 0.25 {\mu}m (emittance ratio is ~400), 0.13 {\mu}m, 15 nm before compression, and 0.41 {\mu}m, 0.20 {\mu}m, 16 nm after full compression, respectively with peak currents as high as 5.5 kA for a 3.2-nC flat beam. These parameters are consistent with requirements needed to excite wakefields in asymmetric dielectric-lined waveguides or produce significant photon flux using small-gap micro-undulators.Comment: 17

Smell you later - the repelling effect of secondary plant compounds against water voles and common voles

Fischer, D., Prokop, A., Wink, M., Mattes, H., Jacob, J

UK Competitiveness Index 2023

The report covers UK Competitiveness Index for 2023. This is a benchmarking study covering the competitiveness of localities (local authority districts) in Great Britain. Measures are also included for Local Enterprise Partnerships (LEPs) and City Regions

UK Competitiveness Index 2021

First introduced and published in 2000, this UK Competitiveness Index (UKCI) report represents the 2021 edition of the report. The UKCI provides a benchmarking of the competitiveness of the UK’s localities, and it has been designed to be an integrated measure of competitiveness focusing on both the development and sustainability of businesses and the economic welfare of individuals. This report publishes competitiveness indices that incorporate the most up-to-date data available in 2021. These data will largely relate to the period since the UK’s departure from the European Union (EU) and the beginning of the Covid-19 Pandemic and associated economic downturn in 2020. As a comparator prior to these major unforeseen (Covid-19 Pandemic) and foreseen (UK’s departure from EU) economic events, an updated UKCI is also generated for 2018. This UKCI will provide a measure of competitiveness prior to these shocks and before the period of greatest uncertainty associated with the UK’s departure from the EU. This provides a means of comparison and an examination of the UK’s changing competitiveness landscape

Study of the island morphology at the early stages of Fe/Mo(110) MBE growth

We present theoretical study of morphology of Fe islands grown at Mo(110) surface in sub-monolayer MBE mode. We utilize atomistic SOS model with bond counting, and interactions of Fe adatom up to third nearest neighbors. We performed KMC simulations for different values of adatom interactions and varying temperatures. We have found that, while for the low temperature islands are fat fractals, for the temperature 500K islands have faceted rhombic-like shape. For the higher temperature, islands acquire a rounded shape. In order to evaluated qualitatively morphological changes, we measured averaged aspect ration of islands. We calculated dependence of the average aspect ratio on the temperature, and on the strength of interactions of an adatom with neighbors.Comment: 6 pages, 6 figures. Proceedings of 11-th Symposium on Surface Physics, Prague 200

Short range order and topology of binary Ge-S glasses

Short range order and topology of GexS100-x glasses over a broad composition range (20 ≤ x ≤ 42 in at%) was investigated by neutron diffraction, X-ray diffraction, and Ge K-edge extended X-ray absorption fine structure (EXAFS) measurements. The experimental data sets were fitted simultaneously in the framework of the reverse Monte Carlo simulation method. It was found that both constituents (Ge and S) satisfy the Mott-rule in all investigated glasses: Ge and S atoms have 4 and 2 neighbours, respectively. The structure of these glasses can be described with the chemically ordered network model: Ge-S bonds are preferred; S-S bonds are present only in S-rich glasses. Dedicated simulations showed that Ge-Ge bonds are necessary in Ge-rich glasses. Connections between Ge atoms (such as edge-sharing GeS4/2 tetrahedra) in stoichiometric and S-rich glasses were analysed. The frequency of primitive rings was also calculated