Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has...

This paper presents the measurement of sub-picosecond relativistic electron beam bunch length by analyzing the spectra of the coherent terahertz pulses through Kramers-Kronig transformation. The results are compared with autocorrelation from a scanning polarization autocorrelator that measures the coherent optical transition radiation. The limitations of the different methods to such a characte...

The exact solution of a problem on electromagnetic field excitation by a thin annular charged bunch in a semi-infinite round cylindrical waveguide with metal sidewalls and solid homogeneous dielectric filling is obtained. Expressions for all components of electromagnetic field are derived. These formulas describe the excited field at any point and any moment of time. In contrast to previous wor...

This paper discusses various aspects of multibunch motion in thepresence of nearest neighbor wakefield coupling. Included are the solution to the problem for smooth focusing with equal bunch energies, an explanation for the apparent &mping of the bunch amplitudes that is observed for weak coupling, and a treatment of the problem for discrete focusing based on the moments of the wakefield distri...

The amplitude of Parametric X-ray radiation emitted coherently by a bunch of electrons crossing a crystal (CPXR) is calculated. When the bunch density is modulated with a longitudinal period close to the X-ray wavelenght, constructive many-electron interferences enhance the intensity by Nb × |F (K)| , where Nb is the number of electrons in the bunch, F (K) the bunch form factor and K a specifie...

In this paper, we have developed a novel block cipher involving a key bunch matrix supported by a key-based permutation and a key-based substitution. In this analysis, the decryption key bunch matrix is obtained by using the given encryption key bunch matrix and the concept of multiplicative inverse. From the cryptanalysis carried out in this investigation, we have seen that the strength of the...

In this paper we try to explain the single bunch energy spread increasing in a proton storage ring. Different from an electron machine, the random motions of some particles of a bunch are caused by the nonlinear synchrotron oscillations perturbed by the short range longitudinal wakefield. An analytical single bunch threshold current formula has been established to indicate the beginning of the ...

Bunch-by-bunch feedback systems for curing coupled-bunch instabilities in the KEKB rings have been constructed. Even at a very early stage of the commissioning of the rings, strong transverse instabilities occurred in both rings which limited maximum storable currents. Stabilization of the beams with transverse feedback systems has been successful so far, enabling us to accumulate greater beam ...

We report on tests of an x-ray beam size monitor based on coded aperture imaging[1]. This technique uses a mask pattern to modulate incoming photons, with the resulting image being deconvolved through the mask and detector responses, including the effects of diffraction and attenuation materials in the path, over the spectral and angular distribution of the synchrotron radiation generated by th...

Oil palm empty fruit bunch is abundantly available as waste from oil processing which only used for boiler fuel and plant fertilizers. This study aims to investigate the utilization of a composite reinforcement material be applied raw outer shell Indonesian national standard (SNI) helmets. The materials include bunch, polyester resin BQTN yukalac, catalyst MEKPO. manufacturing process uses hand...