BNL, Upton, Long Island, New York
Modes with transverse electric field (TE-modes) in the NSLS-II multipole vacuum chamber can be generated at frequencies above 450 MHz due to its geometric dimensions. Since the NSLS-II BPM system is triggered by the RF at 500 MHz, frequencies of higher-order modes (HOMs) can be generated within the transmission band of the band pass filter. In order to avoid systematic errors in the NSLS-II BPM system, we introduced frequency shift of HOMs by using RF metal shielding located in the antechamber slot.
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.
BNL, Upton, Long Island, New York
An internal R&D program has been undertaken at BNL to develop an RF BPM to meet all requirements of both the injection system and storage ring. The RF BPM architecture consists of an Analog Front-End (AFE) board and a Digital Front-End board (DFE) contained in a 1U 19" chassis. An external passive RF signal processor has been developed that will be located near the RF BPM pickups. The partitioning into two boards enables a flexible Software Defined Instrument. A model-based design flow has been adopted utilizing AWR VSS, Simulink, and Xilinx System Generator for algorithm development and AFE impairment performance analysis. The DFE architecture consists of a Virtex-6 with MicroBlaze embedded processor. An optional Intel Atom SBC is also supported. The AFE is based on a bandpass sampling architecture utilizing 16-bit ADCs. Long-term drift is corrected by inclusion of an out-of-band calibration tone. An RF BPM Calibration Tool is being developed for removal of systematic errors and performance verification. In this contribution we will present a detailed overview of the architecture, compare simulation results to laboratory performance, and report beam test results.
BNL, Upton, Long Island, New York
The NSLS-II Injector System Diagnostics will provide instrumentation in the Linac, Booster, transfer lines and beam dumps for measuring key beam parameters. These instruments will be adequate in providing staged commissioning of NSLS-II injectors, as well as allowing sufficient beam diagnostics for tune-up and top up operations. This paper will summarize the progress and implementation status of the NSLS-II injector system diagnostics.