Bagging of female inflorescence following pollination has recently received growers attention. Although this process occurs early in the season but affects fruit quality, yield, and marketability. Date palm growers have used to use grocery paper bags for this bagging process. Since inflorescence bagging causes what is called the greenhouse effect, it was very important to investigate the effect...

A new method of monitoring the luminosity has been developed at CESR. The method involves shaking one bunch at a speciic frequency and observing the resulting oscillations of the corresponding opposing bunch. In initial tests, measurements with 1 accuracy have been obtained in 1 second. Measurements of diierent bunches in a train shows bunch to bunch diierences with the optimum luminosity condi...

In order to study the wakefield effects of an electron cloud, a test bunch was placed behind a bunch train, where the cloud density rapidly varied. A currentdependent tune shift and the tune spread of the test bunch were measured as a function of the bunch current while varying the bucket position of the test bunch. The vertical tune shift indicated a strong defocusing force together with a wid...

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...

Limits on Efficient Computation in the Physical World

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...