967 research outputs found
Simulations on a potential hybrid and compact attosecond X-ray source based on RF and THz technologies
We investigate through beam dynamics simulations the potential of a hybrid
layout mixing RF and THz technologies to be a compact X-ray source based on
Inverse Compton Scattering (ICS), delivering few femtoseconds to
sub-femtosecond pulses. The layout consists of an S-band gun as electron source
and a dielectric-loaded circular waveguide driven by a multicycle THz pulse to
accelerate and longitudinally compress the bunch, which will then be used to
produce X-ray pulses via ICS with an infrared laser pulse. The beam dynamics
simulations we performed, from the photocathode up to the ICS point, allows to
have an insight in several important physical effects for the proposed scheme
and also in the influence on the achievable bunch properties of various
parameters of the accelerating and transverse focusing devices. The study
presented in this paper leads to a preliminary layout and set of parameters
able to deliver at the ICS point, according to our simulations, ultrashort
bunches (around 1 fs rms), at 15 MeV, with at least 1 pC charge and
transversely focused down to around 10 um rms or below while keeping a compact
beamline (less than 1.5 m), which has not yet been achieved using only
conventional RF technologies. Future studies will be devoted to the
investigation of several potential ways to improve the achieved bunch
properties, to overcome the limitations identified in the current study and to
the definition of the technical requirements. This will lead to an updated
layout and set of parameters.Comment: To be published in Nucl. Inst. Meth. A as proceedings of the EAAC17
conference 9 pages, 11 figure
Program transformations using temporal logic side conditions
This paper describes an approach to program optimisation based on transformations, where temporal logic is used to specify side conditions, and strategies are created which expand the repertoire of transformations and provide a suitable level of abstraction. We demonstrate the power of this approach by developing a set of optimisations using our transformation language and showing how the transformations can be converted into a form which makes it easier to apply them, while maintaining trust in the resulting optimising steps. The approach is illustrated through a transformational case study where we apply several optimisations to a small program
Detection of vancomycin resistances in enterococci within 3 1/2 Hours
Vancomycin resistant enterococci (VRE) constitute a challenging problem in health care institutions worldwide. Novel methods to rapidly identify resistances are highly required to ensure an early start of tailored therapy and to prevent further spread of the bacteria. Here, a spectroscopy-based rapid test is presented that reveals resistances of enterococci towards vancomycin within 3.5 hours. Without any specific knowledge on the strain, VRE can be recognized with high accuracy in two different enterococci species. By means of dielectrophoresis, bacteria are directly captured from dilute suspensions, making sample preparation very easy. Raman spectroscopic analysis of the trapped bacteria over a time span of two hours in absence and presence of antibiotics reveals characteristic differences in the molecular response of sensitive as well as resistant Enterococcus faecalis and Enterococcus faecium. Furthermore, the spectroscopic fingerprints provide an indication on the mechanisms of induced resistance in VRE
Beam Dynamics and Tolerance Studies of the THz-driven Electron Linac for the AXSIS Experiment
A dielectric-loaded linac powered by THz-pulses is one of the key parts of
the "Attosecond X-ray Science: Imaging and Spectroscopy" (AXSIS) project at
DESY, Hamburg. As in conventional accelerators, the AXSIS linac is designed to
have phase velocity equal to the speed of light which, in this case, is
realized by tuning the thickness of the dielectric layer and the radius of the
vacuum channel. Therefore, structure fabrication errors will lead to a change
in the beam dynamics and beam quality. Additionally, errors in the bunch
injection will also affect the acceleration process and can cause beam loss on
the linac wall. This paper numerically investigates the process of electron
beam acceleration in the AXSIS linac, taking into account the aforementioned
errors. Particle tracking simulations were done using the code ECHO, which uses
a low-dispersive algorithm for the field calculation and was specially adapted
for the dielectric-loaded accelerating structures.Comment: EAAC'17 conference proceeding
Potential applications of the dielectric wakefield accelerators in the SINBAD facility at DESY
Short, high-brightness relativistic electron bunches can drive ultra-high wakefields in the dielectric wakefield accelerators (DWFAs). This effect can be used to generate high power THz coherent Cherenkov radiation, accelerate a witness bunch with gradient two or three orders of magnitude larger than that in the conventional RF linear accelerators, introduce energy modulation within the driving bunch itself, etc. The paper studies potential applications of the DWFAs in the SINBAD facility at DESY. The simulations show that the ultra-short relativistic bunches from the SINBAD injector ARES can excite accelerating wakefields with peak amplitudes as high as GV/m at THz frequencies in proper DWFA structures. In addition, it illustrates that the DWFA structure can serve as a dechirper to compensate the correlated energy spread of the bunches accelerated by the laser plasma wakefield accelerator
The societal cost of treatment-seeking patients with borderline personality disorder in Germany
According to previous research, borderline personality disorder (BPD) is associated with high cost-of-illness. However, there is still a shortage of cost-of-illness-studies assessing costs from a broad societal perspective, including direct and indirect costs. Further, there are considerable differences in the results among the existing studies. In the present study, 167 German men and women seeking specialized outpatient treatment for BPD were included. We assessed societal cost-of-illness bottom-up through structured face-to-face interviews and encompassed a wide range of cost components. All costs were calculated for the 2015 price level. Cost-of-illness amounted to € 31,130 per patient and year preceding disorder-specific outpatient treatment. € 17,044 (54.8%) were direct costs that were mostly related to hospital treatment. Indirect costs amounted to € 14,086 (45.2%). Within indirect costs, costs related to work disability were the most crucial cost driver. The present study underlines the tremendous economic burden of BPD. According to the present study, both the direct and indirect costs are of significant importance for the societal costs associated with BPD. Besides the need for more disorder-specific treatment facilities for men and women with BPD, we assume that education and employment are topics that should be specifically targeted and individually supported at an early stage of treatment. Trial Registration: German Clinical Trial Registration, DRKS00011534, Date of Registration: 11/01/2017, retrospectively registered
A High Luminosity e+e- Collider to study the Higgs Boson
A strong candidate for the Standard Model Scalar boson, H(126), has been
discovered by the Large Hadron Collider (LHC) experiments. In order to study
this fundamental particle with unprecedented precision, and to perform
precision tests of the closure of the Standard Model, we investigate the
possibilities offered by An e+e- storage ring collider. We use a design
inspired by the B-factories, taking into account the performance achieved at
LEP2, and imposing a synchrotron radiation power limit of 100 MW. At the most
relevant centre-of-mass energy of 240 GeV, near-constant luminosities of 10^34
cm^{-2}s^{-1} are possible in up to four collision points for a ring of 27km
circumference. The achievable luminosity increases with the bending radius, and
for 80km circumference, a luminosity of 5 10^34 cm^{-2}s^{-1} in four collision
points appears feasible. Beamstrahlung becomes relevant at these high
luminosities, leading to a design requirement of large momentum acceptance both
in the accelerating system and in the optics. The larger machine could reach
the top quark threshold, would yield luminosities per interaction point of
10^36 cm^{-2}s^{-1} at the Z pole (91 GeV) and 2 10^35 cm^{-2}s^{-1} at the W
pair production threshold (80 GeV per beam). The energy spread is reduced in
the larger ring with respect to what is was at LEP, giving confidence that beam
polarization for energy calibration purposes should be available up to the W
pair threshold. The capabilities in term of physics performance are outlined.Comment: Submitted to the European Strategy Preparatory Group 01-04-2013 new
version as re-submitted to PRSTA
Proposed Beam Test of a Transverse Gradient Undulator at the SINBAD Facility at DESY
While Laser Plasma Accelerators produce beams with the high output energy required for FELs, up to now the relatively high energy spread has prohibited FEL lasing. Therefore it was proposed to replace the normal FEL undulators by Transverse Gradient Undulators (TGUs). For a first, small scale test of the TGU concept, a 40 period prototype high gradient superconductive TGU was built at KIT and will be tested with beam at the ARES-linac in the new accelerator test facility SINBAD (Short Innovative Bunches and Accelerators at Desy) at DESY. The proposed tests are summarized in this paper
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