We present a real-time complex amplitude reconstruction method for determining the beam propagation ratio M2 of laser beams based on the transport of intensity equation (TIE). In this work, a synchronous acquisition system consisting of two identical CCDs is established. Once two beam intensity images at different cross-section positions along the optical axis are captured simultaneously by the...

Analysis of a laminated composite beam under impact by a rigid particle is investigated. The importance of this project is to simulate the impact of objects on small scale aerial structures. The stresses are considered uni- axial bending with no torsion loading. The first order shear deformation theory is used to simulate the beam. After obtaining kinematic and potential energy for a laminated ...

We report experimental results demonstrating 54% power conversion efficiency ~43% energy conversion efficiency!, from a two-stage X-band traveling wave tube amplifier designed for high-power operation. The first stage of the amplifier is a 12-cm-long Boron Nitride dielectric section used to modulate the electron beam. The second stage consists of a long high-phase-velocity bunching section foll...

The feedback system has been developed in KU-FEL linac to stabilize the FEL power fluctuation. The system consists of six 4-button type BPMs and the signal processing system. As the first step, the beam displacement information at the RF-gun section was used for the feedback control to stabilize the electron energy and the vertical beam position at the RF-gun section. As the result the FEL powe...

An electron energy measurement setup based on the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam, has been proposed and developed for operation at the ANKA storage ring of the Karlsruhe Institute of Technology (KIT). In contrast to conventional methods based on head-on collisions, the setup at ANKA is, for the first time, realiz...

The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finitesize beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary ...

This note determines the profile of the power input into an accelerator section during one fill time prior to beam injection required to reduce the transient beam energy spread to zero, for any group velocity profile along the section, and for any variation of shunt resistance and Q with group velocity. It confirms that the field (the square root of the power) has to be linear for a true consta...

We propose a method for the separation of long DNA molecules, based on elastomeric nanochannels with tunable cross section. These nanoconfinement structures can be used to stretch DNA molecules and lower their conformational entropy. The sieving mechanism of entropic recoil, proposed by Cabodi et al. [1], will be implemented using an array of elastomeric nanocheannels. Structures of various dim...

Cavity-type beam position monitors were developed to measure the beam alignment at the undulator section of DESY’s TESLA Test Facility (TTF). This paper describes some theoretical aspects and the experimental setup. The results of some in-beam measurements at the TTF are presented and pros and cons of the monitor concept are discussed.

The ISAC II superconducting linac is presently in the beam commissioning phase. The linac lattice consists of modules of four quarter wave cavities and one superconducting solenoid. At the moment five cryomodules (indicated as medium beta section) are installed. Beam steerers between cryomodules compensate for steering effects due to misalignments in the solenoids. Beam dynamics aspects of lina...