Overview of charged-particle beam diagnostics for the Advanced Photon Source (APS)

Plans, prototypes, and initial test results for the charged-particle beam (e[sup [minus]],e[sup +]) diagnostic systems on the injector rings, their transport lines, and the storage ring for the Advanced Photon Source (APS) are presented. The APS will be a synchrotron radiation user facility with one of the world's brightest x-ray sources in the 10-keV to 100-keV regime. Its 200-MeV electron linac, 450-MeV positron linac, positron accumulator ring, 7-GeV booster synchrotron, 7-GeV storage ring, and undulator test lines will also demand the development and demonstration of key particle-beam characterization techniques over a wide range of parameter space. Some of these parameter values overlap or approach those projected for fourth generation light sources (linac-driven FELs and high brightness storage rings) as described at a recent workshop. Initial results from the diagnostics prototypes on the linac test stand operating at 45-MeV include current monitor data, beam loss monitor data, and video digitization using VME architecture

Initial optical transition radiation measurements of the electron beam for the Boeing Free-Electron Laser experiment

The potential for characterization of electron beams at {approximately}100 MeV at the Boeing Free-Electron Laser (FEL) facility by optical transition radiation (OTR) techniques has been demonstrated as an important complement to other diagnostic means. Electron beam properties such as spatial profile and position, current intensity, emittance, and energy were made accessible in an on-line manner. Initial examples including transport through the 5-m wiggler and the resolution of Cerenkov radiation and spontaneous emission radiation competitive sources are discussed. 11 refs., 13 figs

Digital Signal Processing for the APS Transverse and Longitudinal Damping System

The Advanced Photon Source (APS) at Argonne National Laboratory will be a 7-GeV machine. It is anticipated that for beam operations beyond the baseline design of 100 mA stored beam current, a transverse and longitudinal damping system is needed to damp instabilities. A key part of this digital damping system is digital signal processing. This digital system will be used to process samples taken from the beam and determine appropriate correction values to be applied to the beam. The processing will take the form of a transversal digital filter with adaptable filter weights. Sampling will be done at 176 MHz with a possible correction bandwidth of 88 MHz. This paper concentrates on the digital processing involved in this system, and especially on the adaptive algorithms used for determining the digital filter weights. I. INTRODUCTION If there are no interactions between circulating bunches of a synchrotron, the motion of each bunch can be described by three harmonic oscillators corresp..

Digital signal processing for the APS transverse and longitudinal damping system

The Advanced Photon Source (APS) at Argonne National Laboratory will be a 7-GeV machine. It is anticipated that for beam operations beyond the baseline design of 100 mA stored beam current, a transverse and longitudinal damping system is needed to damp instabilities. A key part of this digital damping system is digital signal processing. This digital system will be used to process samples taken from the beam and determine appropriate correction values to be applied to the beam. The processing will take the form of a transversal digital filter with adaptable filter weights. Sampling will be done at 176 MHz with a possible correction bandwidth of 88 MHz. This paper concentrates on the digital processing involved in this system, and especially on the adaptive algorithms used for determining the digital filter weights

A Low-Frequency RFQ for a Low-Charge-State Injector for ATLAS

A design for a split-coaxial, normally-conducting, 12 MHz RFQ structure is being developed to accelerate singly charged ions of mass 132 and heavier to a velocity v/c = 0.008, suitable for injection into the ATLAS superconducting heavy-ion linac. Numerical studies have shown that a transverse (normalized) acceptance of 0.25 {pi} mm-mrad can be achieved while maintaining a longitudinal emittance as small as a few keV-nsec. A novel feature is the use of drift-tubes at the entrance and exit of the RFQ which make use of the voltage offsets intrinsic to the split-coaxial structure to increase the voltage gain by about 30%. A half-scale model of the RFQ has been built and tested. The model, with no provision for cooling, was not operable cw but was pulsed to vane-vane voltages as high as 59 kV for periods of several milliseconds. The achieved level, limited by arcing in an rf feedthrough and so not a fundamental limit for the structure, corresponds to 1.2 times the (frequency and gap dependent) Kilpatrick limit. Assuming the model results scale, a 2 meter long 12 MHz RFQ, with 8 mm minimum aperture radius, will operate at 100 kV intervane voltage with an RF input of slightly less than 25 kW. Design and construction status of a full-scale prototype is discussed

Bench Test of a Residual Gas Ionization Profile Monitor (RGIPM)

An RGIPM has been designed, constructed and bench tested to verify that all components are functioning properly and that the desired resolution of about 50μm× rms can be achieved. This paper will describe some system details and it will compare observed results to detailed numerical calculations of expected detector response

Diagnostics for the APS undulator test line

One of the research and development thrusts at the Advanced Photon Source (APS) is to use an rf gun as a low-emittance electron source for injection into the 100- to 650-MeV linac subsystem and subsequent transport to an undulator test area. This configuration would combine the acceleration capability of the 200-MeV S-band electron linac and the in-line 450-MeV positron linac that normally provide positrons to the positron accumulator ring (PAR). A transport line that bypasses the PAR will bring the electrons to the undulator test area. Characterization techniques will be discussed for the electron beam with a normalized, rms emittance of <10 {pi} mm mrad (l{sigma}) at micropulse charges of up to 350 pC and micropulse durations of {approximately}5 ps (FWHM). Preservation of such beam properties will be critical. The diagnostics planned, with resolutions in parentheses, include the beam position monitors based on stripline pickups (100 {mu}m), current monitors based on a transformer (60 {mu}A), beam profile monitors (25 {mu}m FWHM), and bunch length monitor based on a streak camera (2 ps). Tests proposed include measurement of particle beam transport effects (at one-tenth the storage ring beam rigidity) caused by small undulator field errors