For several years, a large variety of beams have been prepared in the LHC injectors, such as single-bunch and multi-bunch beams, with 25 ns, 50 ns and 75 ns bunch spacings, nominal and intermediate intensities per bunch. As compared to the nominal LHC beam (i.e. with nominal bunch intensity and 25 ns spacing) the other beams can be produced with lower transverse emittances. Beams of low transve...

In order to achieve high luminosity in CLIC, ultra-low emittance bunches have to be generated in both electron and positron damping rings. To achieve this goal, big energy loss per turn in the wigglers has to be compensated by the RF system. This results in very strong beam loading transients affecting the longitudinal bunch position and bunch length. In this paper, the conceptual design of the...

The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30-50 MeV m(-1) gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequen...

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...

For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task es...

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 ...