LANL, Los Alamos, New Mexico
The goal of the design LANSCE-R Wire-Scanner Analog Front-end Electronics is to develop a high-performance, dual-axis wire-scanner analog front-end system implemented in a single cRIO module. This new design accommodates macropulse widths as wide as 700 us at a maximum pulse rate of 120 Hz. A lossey integrator is utilized as the integration element to eliminate the requirement for providing gating signals to each wire scanner. The long macropulse and the high repetition rate present conflicting requirements for the design of the integrator. The long macropulse requires a long integration time constant to assure minimum integrator droop for accurate charge integration, and the high repetition rate requires a short time constant to assure adequate integrator reset between macropulses. Also, grounding is a serious concern due to the small signal levels. This paper reviews the basic Wire Scanner AFE system design implemented in the cRIO-module form factor to capture the charge information from the wire sensors and the grounding topology to assure minimum noise contamination of the wire signals.
Fermilab, Batavia
CERN, Geneva
In the context of the development of a high resolution BPM system for the CLIC Main Linac we present the design of a cavity BPM prototype. It consists of a waveguide loaded dipole mode resonator and a monopole mode reference cavity, both operating at 15 GHz, to be compatible with the bunch frequencies at the CLIC Test Facility. Requirements, design concept, numerical analysis, and practical considerations are discussed.
BNL, Upton, Long Island, New York
The NSLS-II Light Source is being built at Brookhaven National Laboratory. It will provide users with ultimate brightness beam and the full realization of its capabilities requires corresponding stability of the beam orbit. The small aperture BPMs, located at the ends of a insertion device, will provide better sensitivity to the beam position but also requires thorough design. In this paper we present the results of the optimization including signal power levels and button heating.
KEK, Ibaraki
Button-type beam position monitors for SuperKEKB rings have been designed. The RF characteristics such as beam response, trapped modes or wake functions have been simulated using 3-D E-M codes such as GdfidL and HFSS. The estimated instability threshold from the trapped modes was much higher than the radiation damping time. The prototype units have been tested in the prototype-antechambers installed in KEKB and KEK-PF BT line. The mechanical reliability and the beam responses are also reported.
CERN, Geneva
A high resolution beam position monitor (BPM) electronics based on diode peak detectors has been developed at CERN. The circuit processes the BPM electrode signals independently, converting the short beam pulses into slowly varying signals which are digitized with high resolution ADCs operating in the kHz range. For large enough amplitudes the non-linear forward voltage of the diodes is compensated by a simple network using signals from single-diode and double-diode peak detectors. This contribution discusses the performance of the built prototype with beam in the CERN-SPS and comments on possible future applications of the technique.
BNL, Upton, Long Island, New York
AC-dipole magnets are typically implemented as a parallel LC resonant circuit. To maximize efficiency, it’s beneficial to operate at a high Q. This, however, limits the magnet to a narrow frequency range. Current designs therefore deliberately spoil the Q to provide a wider bandwidth at the cost of efficiency. Dynamically tuning the resonant circuit tries to maintain a high efficiency while providing a wide frequency range. The results of ongoing efforts at BNL to implement dynamically tuned high-Q AC dipoles will be presented.
BNL, Upton, Long Island, New York
A diffraction-limited storage ring like NSLS2 sets more stringent beam stability requirements. Due to resistive wall impedance and fast-ion effect, transverse instabilities will happen at low current (~15 mA). An active transverse feedback system has been designed to cure the betatron oscillations. The system will have a <200 us damping rate at 50 0mA to suppress the fast-ion instability, which is severe in the vertical plane due to small beam size.