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To get information about arrival of the electron bunch relative to the laser pulse; electro-optic detection scheme in near-crossed polarizer configuration was set up and tested. Electron bunch induced birefringence in ZnTe crystal leaves a polarization footprint in a chirped infrared pulse. The IR pulse is sampled before third harmonic generation from the amplifier, stretched and synchronized to t
A facility for seeding and harmonic generation utilizing an optical klystron is under commissioning at MAX-lab. The facility utilizes the 400 MeV linac accelerator, improved operation of an RF-gun, an undulator system of two undulators and a magnetic chicane and combined laser system for gun and seeding. The goal is to seed the electron beam at 263 nm and generate the harmonics 2-5 (131-53 nm). Cu
A European project to develop the first storage ring free-electron laser on a third-generation synchrotron radiation facility is presented, including a description of the main features, initial performance at 350 and 220 nm and future prospects.
A method to achieve spatial bunching on the double frequency of the induced energy spread in an optical klystron is described. Criteria necessary to construct such a second order buncher and the phase space evolution are presented.
The initial concept of the electromagnetic elliptical wiggler (EEW) for ELETTRA is a combination of a vertical permanent magnet to generate a wiggler field and a horizontal electromagnet to provide the possibility of switching the helicity of the X-ray radiation. The main aspects of the design of the EEW under construction for ELETTRA are discussed.
We present the results of extensive beam dynamic simulations that have been carried out in order to study the non-linear effects of an electromagnetic elliptical wiggler, presently under construction for ELETTRA, using different symplectic tracking methods implemented in the codes BETA and RACETRACK.
An FEL test facility is built on the existing MAX-lab linac system in collaboration between MAX-lab and BESSY. The goal is to study and analyse seeding, harmonic generation, beam compression and diagnostic techniques with the focus of gaining knowledge and experience for the MAX IV FEL and the BESSY FEL projects. The test facility will in the first stage be using the 400 MeV linac beam to generate
An undulator operating at radiation wavelengths between 250 and 2000 Å has been constructed at the Technical Research Centre of Finland and recently installed at the MAX storage ring in Lund. The undulator utilizes ferrite permanent magnets in the hybrid configuration. The magnetic and mechanical design, calculated performance and influence on the electron beam of the undulator are discussed.
Though the pandemic has passed, social media-based messaging continues to exhibit COVID-19-related cues (e.g., wearing a face mask to stay safe), continuing to foster consumers’ health-protective behavior. However, it remains unclear how social media communications (e.g., advertising) affect such behavior, exposing an important literature-based gap. Addressing this gap, we deploy Ducoffe’s adverti
A growing number of primary school students experience difficulties with grapho-motor skills involved in handwriting, which impact both form and content of their texts. Therefore, it is important to assess and monitor handwriting skills in primary school via standardized tests and detect specific grapho-motor parameters (GMPs) which impact handwriting legibility. Multiple standardized tools are av
This paper describes the shape optimization of hyperelastic structures exhibiting finite deformation and contact. The structure's shapes are parameterized with B-splines and the spline control point coordinates serve as the design variables. This design parametrization provides precise boundary representations and analytical sensitivity computations. To accommodate non-matching grids between the c
We show that the Hausdorff dimension of the closure of the second Grigorchuk group is 43/128. Furthermore, we establish that the second Grigorchuk group is super strongly fractal and that its automorphism group equals its normalizer in the full automorphism group of the tree.
The class of multi-EGS groups is a generalisation of the well-known Grigorchuk–Gupta–Sidki (GGS-)groups. Here we classify branch multi-EGS groups with the congruence subgroup property and determine the profinite completion of all branch multi-EGS groups. Additionally, our results show that branch multi-EGS groups are just infinite.
Let w be a word in k variables. For a finite nilpotent group G, a conjecture of Amit states that Nw(1) ≥ | G| k-1, where for g∈ G, the quantity Nw(g) is the number of k-tuples (g1, … , gk) ∈ G(k) such that w(g1, … , gk) = g. Currently, this conjecture is known to be true for groups of nilpotency class 2. Here we consider a generalized version of Amit’s conjecture, which states that Nw(g) ≥ | G| k-
For a generalized (or non-central) camera model, the minimal problem for two views of six points has efficient solvers. However, minimal problems of three views with four points and three views of six lines have not yet been explored and solved, despite the efforts from the computer vision community. This paper develops the formulations of these two minimal problems and shows how state-of-the-art
Research connecting text and images has recently seen several breakthroughs, with models like CLIP, DALL•E 2, and Stable Diffusion. However, the connection between text and other visual modalities, such as lidar data, has received less attention, prohibited by the lack of text-lidar datasets. In this work, we propose LidarCLIP, a mapping from automotive point clouds to a pre-existing CLIP embeddin
The following problem was originally posed by B. H. Neumann and H. Neumann.Suppose that a group can be generated by elements and that is a homomor-phic image of . Does there exist, for every generating -tuple (ℎ1, … , ℎ ) of ,a homomorphism ∶ → and a generating -tuple (1, … , ) of such that( 1 , … , ) = (ℎ1, … , ℎ )?M. J. Dunwoody gave a negative answer to this question, by means of a carefullyeng
