Dipole magnet using permanent magnet technology is under investigation for ILC. It can reduce the cost of electricity for coil excitation and cooling water pump, thick electric cabling and water ...piping, power supply, and their maintenance cost. The structure and the field adjustment scheme of a trial conceptual design will be discussed.
The development of linac-based narrow-band THz sources with sub-picosecond, Formula: see text-level radiation pulses is in demand from the scientific community. Intrinsically monochromatic emitters ...such as coherent Smith-Purcell radiation sources appear as natural candidates. However, the lack of broad spectral tunability continues to stimulate active research in this field. We hereby present the first experimental investigation of coherent grating diffraction radiation (GDR), for which comparable radiation intensity with central frequency fine-tuning in a much wider spectral range has been confirmed. Additionally, the approach allows for bandwidth selection at the same central frequency. The experimental validation of performance included the basic spectral, spatial and polarization properties. The discussion of the comparison between GDR intensity and other coherent radiation sources is also presented. These results further strengthen the foundation for the design of a tabletop wide-range tunable quasi-monochromatic or multi-colour radiation source in the GHz-THz frequency range.
Coherent radiation spectrum measurements at KEK LUCX facility Shevelev, M.; Aryshev, A.; Araki, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2015, Letnik:
771
Journal Article
Recenzirano
This paper demonstrates the detailed design concept, alignment, and initial testing of a Michelson interferometer for the THz spectral range. We present the first results on the measurement of a ...coherent transition radiation spectrum and describe the performance of a pair of ultra-fast broadband room temperature Schottky barrier diode detectors. We discuss the main criteria of interferometer beam splitter optimization, the alignment technique, the high-precision calibration and linearity check of the motion system.
Momentum bandwidth is an important characteristic for final focus systems (FFS) of future high-energy colliders. A large momentum bandwidth is a notable feature of the novel ...local-chromaticity-correction FFS, being demonstrated at the KEK Accelerator Test Facility 2 (ATF2), owing to the locality of chromaticity correction. In this article, analytical estimations and simulations of momentum bandwidth for various optics of ATF2 are presented. Possible deviations of the momentum bandwidth due to realistic machine imperfections are studied. Experimental measurements at ATF2 following successful tuning of small vertical beam size at the interaction point (IP) are also described, which agree well with numerical predictions and further verify the robustness of the local chromaticity correction scheme.
The interest in producing ultrashort electron bunches has risen sharply among scientists working on the design of high-gradient wakefield accelerators. One attractive approach generating electron ...bunches is to illuminate a photocathode with a train of femtosecond laser pulses. In this paper we describe the design and testing of a laser system for an rf gun based on a commercial titanium-sapphire laser technology. The technology allows the production of four femtosecond laser pulses with a continuously variable pulse delay. We also use the designed system to demonstrate the experimental generation of an electron microbunch train obtained by illuminating a cesium-telluride semiconductor photocathode. We use conventional diagnostics to characterize the electron microbunches produced and confirm that it may be possible to control the main parameter of an electron microbunch train.
A beam halo collimator was installed at the Accelerator Test Facility ATF2 in the spring of 2016. The main objective of the collimator is the reduction of background photons that limit the ...performance of key diagnostic devices around the Interaction Point, especially the Shintake Monitor, used for measuring the nanometer level vertical beam sizes, and the vertical and horizontal Diamond Sensors, used for transverse beam halo measurements. In this paper we present the simulations performed to optimize the efficiency of the collimator as well as the wakefield study performed in order to optimize the geometry and material of the collimator jaws. Finally, measurements of the cleaning efficiency and of the collimator induced wakefields impact on the orbit, performed during the Spring and Fall 2016 runs, are presented and compared with simulations.
A cycle of measurements of the polarization characteristics of coherent transition radiation and coherent diffraction radiation at the LUCX accelerator has been performed. It has been shown that the ...results of measurements of the linear polarization component in both cases are well described by a theoretical model according to which the degree of elliptical polarization of diffraction radiation is close to 100%. This fact indicates a significant contribution (up to 90%) of the circularly polarized component of diffraction radiation for radiation angles with respect to the direction of mirror reflection exceeding γ
−
; (γ is the Lorentz factor).
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