Hard photons well above 100GeV have to be generated in a future photon-collider which essentially will be based on the infrastructure of the planned International Linear Collider (ILC). The energy of near-infrared laser photons will be boosted by Compton backscattering against a high energy relativistic electron beam. For high effectiveness, a very powerful lasersystem is required that exceeds ...

It has been shown that high performance cavity BPM's are capable of accurate beam trajectory angle and beam ‘tilt’, (x-z or y-z correlation) measurements [1],[2]. Such a device will be very useful for the optimization of a variety of beamlines, such as high current linacs, bunch rotators and storage rings. The signal from a non-axial trajectory or a tilted beam is in quadrature to that observed...

In this paper we consider the design of a four-cavity microwave circuit for a high-gain K-band gyroklystron. The goal is to use this device to test a high gradient linear accelerator structure. The frequency doubling circular gyroklystron uses a beam voltage of 500 kV, beam current of 200 A in the circular TE011 mode and provides an output in the TE021 mode. We study the behavior of the four-ca...

Superconducting accelerator technology is celebrating an anniversary this year. Ten years ago, in 1962, Q’s in the range 166-169 and peak rf mangetic fields on the order of 100 G were obtained in measurements on leadplated, S-band cavities at Stanford. While the theoretical possibility of building superconducting linear accelerators had been considered previously, these results marked, if not t...

At Peking University (PKU) a new helium injector for coupled radio frequency quadrupole(RFQ) and separated function radio frequency quadrupole(SFRFQ) within one cavity, so called as coupled RFQ & SFRFQ, was designed recently[1]. It will provide a 30keV 10mA He beam whose emittance is less than 0.15 π.mm.mrad for the accelerator. It is a combination of a 2.45GHz PKU permanent magnet electron cyc...

The FLASH (Free Electron Laser in Hamburg) (Ackermann et al., 2007) is a user facility providing high brilliant laser light for experiments. It is also a unique facility for testing the superconducting accelerator technology for the European XFEL (Weise, 2004) and the International Linear Collider (Ross et al., 2011). The LLRF (low level RF) system is used to maintain the beam stabilities by st...

The present state of progress in laser wakefield acceleration encourages considering it as a practical alternative to conventional particle accelerators. A promising application would be use laser-plasma accelerator an injector for synchrotron light source. Yet, the energy spread and jitter beam pose significant difficulty efficient injection. In this paper, we propose design prototype deliver ...

Mid-infrared laser absorption spectroscopy utilizing a high-finesse optical cavity enables high precision trace analysis of gas molecules. In particular, detection radiocarbon ( 14 C) based on ringdown using quantum cascade (QCL) is gaining attention as an alternative to accelerator mass spectrometry. This paper reports compact-packaged narrow-linewidth QCL system resonant feedback from externa...

This paper presents an updated estimate of the higher-order mode impedance spectrum of the RF cavities for the PEP-II B-factory. The cavity is designed for continuous operation at 476 MHz with up to 150 kW wall dissipation and heavy beam loading. To reduce the growth rates of coupled-bunch instabilities the cavity higher-order modes are damped by three rectangular waveguides and broad-band load...

At SLAC, a 5-cell, normal-conducting, L-band (1.3 GHz), standing-wave (SW) cavity was built as a prototype positron capture accelerator for the ILC. The structure met the ILC gradient goal but required extensive rf processing. When rf breakdowns occurred, a large variation was observed in the decay rate of the stored energy in the cavity after the input power was shut off. It appeared that the ...