The SuperB project has the goal to build in Italy, in the Frascati or Tor Vergata area, an asymmetric e+/eSuper Flavor Factory to achieve a peak luminosity > 10**36 cm-2 s-1. The SuperB design is based on collisions with extremely low vertical emittance beams and high beam currents. A source of emittance growth comes from the bunch by bunch feedback systems producing high power correction signa...

A new regime of laser wakefield acceleration of an injected electron bunch is described. In this regime, the bunch charge is so high that the bunch wakefields play an important role in the bunch dynamics. In particular, the transverse bunch wakefield induces a strong self-focusing that suppresses the transverse emittance growth arising from misalignment errors. The decelerating longitudinal bun...

A new bunch-by-bunch beam position measurement (BPM) prototype has been designed and built to monitor the beam instability and analyse the beam trip in the BEPCII (Beijing Electron-Positron ColliderII) machine. The broadband electronics system which employs fast analogy digital converter (ADC) and field programmable gate array (FPGA) can obtain the beam information bunch-by-bunch with high bunc...

The DSP-based bunch-by-bunch feedback system installed in the PEPII high-energy ring (HER) has been used to damp instabilities induced by unwanted higher-order modes (HOMs) at beam currents up to 605 mA during commissioning. Beam pseudospectra calculated from feedback system data indicate the presence of coupled-bunch modes that coincide with a previously observed cavity mode (0-M-2). Bunch cur...

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste [1]. LAYOUT AND DESIGN PARAMETERS The FERMI accelerator layout is schematically shown in Figure 1. It consists of an injector, four linacs, two bunch compressors, a laser heater, and a spreader used to direct the electron beam into one of tw...

The endeavour to reach higher brightness of electron beams in designs of future FEL is often challenged by the coherent synchrotron radiation (CSR) effect in bunch compression chicanes. Extensive studies on the CSR effects have shown that the 1D approximation of the CSR force is valid for a wide parameter regime. However, as the bunch gets increasingly compressed in the chicane, the behaviour o...

Abstract A THz-pulse-driven compact, < 150 mm in total length, two-stage electron accelerator setup was designed. It uses 2 × pairs of nearly counter-propagating focused THz pulses. The effects the initial bunch charge and propagation direction pulses on energy accelerated electrons were investigated by numerical simulations. Generation 8 fC bunches with up to 340 keV energy; only 2.0% sprea...

The proposed PEP II B factory at SLAC requires a feedback to damp out longitudinal synchrotron oscillations. A time domain, downsampled, bunch-by-bunch feedback system in which each bunch is treated as an oscillator being driven by disturbances from other bunches is presented as we review the evolution of the system design. Results from a synchrotron oscillation damping experiment conducted at ...

We present the design and performance of a highresolution, high charge sensitivity imaging camera system for the APS linac beam profile measurement. Electron beam distribution is converted to light intensity distribution using standard YAG or optical transition radiation (OTR) screens. Two CCD cameras share the light through a beam splitter, each with its own imaging optics. One camera is norma...

every year large amounts of grapes are stores in normal and cold rooms to offer off-season of grapes to the market which based on several reasons their quality and weight greatly decreases. therefore, in order to decrease the post harvest losses of grapes and selection of suitable cultivars for long time storage, this study was conducted in two experiments, one in a factorial experiment based o...