Since spring, 2005 vacuum ultraviolet free electron laser (VUV FEL) at DESY operates as user facility in the wavelength range around 30 nm. Electron beam formation system at the VUV FEL is essentially nonlinear and naturally results in a formation of a short high-current leading peak in the density distribution that produces FEL radiation. The main feature of the femtosecond mode of operation o...

After successful completion of the High Gain Harmonic Generation (HGHG) free electron laser (FEL) experiment [1,2] at the Accelerator Test Facility (ATF), R&D toward future light sources at the NSLS achieved another milestone on March 17, 2001 when the visible-infrared self-amplified spontaneous emission amplifier (VISA) experiment at the ATF achieved saturation. The VISA Self Amplified Spontan...

The Feedback Error Learning (FEL) for Functional Electrical Stimulation (FES) controller was examined through computer simulation using a musculoskeletal model. Feedforward controller of the FEL controller consisted of the inverse dynamics model (IDM) and the inverse statics model (ISM) in order to achieve successful learning. The new controller showed better performance in learning of the feed...

Methods We select 105 sensitized patients to cat. Specific IgE measurement to cat allergens Fel d1, Fel d2 and Fel d4 was performed by ImmunoCAP and/or microarray ISAC (ThermoFisher Scientific, Sweden), a value > 0,35 kU/L or >0,3 ISU was considered as positive, respectively. Skin prick test was performed with an ALK-Abelló extract (Denmark). Association of Specific IgE measurements and presenc...

This review is focused on free-electron lasers (FELs) in the hard to soft x-ray regime. The aim is to provide newcomers to the area with insights into: the basic physics of FELs, the qualities of the radiation they produce, the challenges of transmitting that radiation to end users and the diversity of current scientific applications. Initial consideration is given to FEL theory in order to pro...

The integrated-FEL concept is proposed as an alternative approach for the discrete compact-FELs [1]. In the proposed integrated-FEL, the accelerator and the wiggler are integrated for the sake of compaction. Two examples of integrated-FEL schemes are presented here briefly in order to demonstrate the FEL-integration concept: a) A functional integration scheme is shown in fig. 1. Two electron be...

Allergic responses can be triggered by structurally diverse allergens. Most allergens are proteins, yet extensive research has not revealed how they initiate the allergic response and why the myriad of other inhaled proteins do not. Among these allergens, the cat secretoglobulin protein Fel d 1 is a major allergen and is responsible for severe allergic responses. In this study, we show that sim...

The commissioning of a terahertz-field-driven streak camera installed at the free-electron laser (FEL) FLASH at DESY in Hamburg, being able to deliver photon pulse duration as well as arrival time information with ∼10 fs resolution for each single XUV FEL pulse, is reported. Pulse durations between 300 fs and <15 fs have been measured for different FLASH FEL settings. A comparison between the X...

Radiation safety is one of the most important issues for free electron laser [FEL] facilities and the users. Many FEL facilities are under operation worldwide, and their number is growing. The wave length of FEL ranges from a few millimeters to about 0.5 nm, and the electron energy is from a few MeV to about 20 GeV. Furthermore, various kinds of electron accelerator types are constructed for FE...

A large amplitude upper hybrid wave has potential to be employed as a wiggler for the generation of high frequency coherent radiation via free electron laser (FEL) instability. At a density fluctuation level of a few percent, due to the upper hybrid wave, the growth time of FEL instability, with electron beam current of a few kilo ampere, turns out to be of the order of a nanosecond. The growth...