The aluminum bending chambers for the Taiwan Photon Source (TPS) is designed to meet the requirement of ultra high vacuum condition for the electron beam of 3 ~ 3.3 GeV and 400 mA. The crotch absorbers are located far from the source to reduce the synchrotron radiation power density thus the design of the cooling is simple. A program of finite element analysis is applied to simulate the thermal...

Synchrotron radiation induced photodesorption in particle accelerators may lead to pressure rise and to beam-gas scattering losses, finally affecting the beam lifetime [1]. We discuss the beam tube vacuum in the low field Stage 1 and Stage 2 Very Large Hadron Collider VLHC. Since VLHC Stage 1 has a room temperature beam tube, a non-evaporable getter (NEG St101 strip) pumping system located insi...

As a result of the synchrotron radiation from a positivelycharged beam, an electron cloud is expected to develop in the vacuum chamber from the combined effects of the photoelectric and secondary emission processes [1–3]. We provide here a first estimate of the electron-cloud effect on individual particles of the beam. We focus on the spacecharge tune spread, the distortion of the beta function...

With a pulsed electron beam a gas mixture of Ar, Xe, and Rb was excited producing (XeRb) + ionic excimer molecules. To study the formation kinetics the (XeRb) + fluorescence pulse was measured as a function of the gas composition and the pumping density. From the observed fluorescence signal decay a value of 6k 1 X 10m3’ cm”/s for the formation rate constant of (XeRb) + from Xe+, Ar, and Rb was...

Flat-top, Ar-Xe laser pulses at 1.73 ,um have been achieved by pumping the laser medium with a constant-current electron beam for pulse durations of up to 2.5 ms. The 220 keV electron beam pumped an active volume of 50X 8X6 cm3 at power loadings of 6-100 W/cm3. Small signal gain, saturation flux, and nonsaturable absorption were determined as a function of Xe concentration, total gas pressure, ...

There have been a considerable number of studies on alkali molecular diffuse bands concerning their excimertype nature.’ Such diffuse bands might be developed as possible sources of tunable, high-power lasers.2 Fluorescence of a Naa violet diffuse band could be observed either by one-photon excitation of X’c,’ w C’II, or two-photon excitation of an X’c,’ -+ A’C: -+ high-lying g state in Na,, or...

A mechanism for generating large (>1 GeV/m) accelerating wakes in a plasma is proposed. Two slightly detuned counterpropagating laser beams, an ultrashort timing pulse and a long pump, exchange photons and deposit the recoil momentum in plasma electrons. This produces a localized region of electron current, which acts as a virtual electron beam, inducing intense plasma wakes with phase velocity...

We consider optical pumping with a quasi monochromatic tunable light beam, in the low intensity limit where a rate equation regime is obtained The velocity selective optical pumping (V.S.O.P.) introduces a correlation between atomic velocity and internal variables in the ground (or metastable) state. The aim of this article is to evaluate these atomic observables (orientation, alignment, popula...