CERN, Geneva
This presentation will detail the performance achieved to date with all the main LHC beam instrumentation systems. It will include an overview of the beam loss system and its role in machine protection, along with that of the beam position system and its use for automatic orbit control. Results will be shown from the highly sensitive base band tune system as well as the bunch-by-bunch and DC beam current transformer systems, the synchrotron light monitoring systems, the wire scanner system and OTR screens. It will also cover the US-LARP contribution to the LHC in the form of results from the collision rate monitors developed by LBL and the Schottky monitors developed by FNAL.
Diamond, Oxfordshire
With refined lattice tuning it becomes increasingly important to monitor or feedback on many parameters to keep stable optimum operating conditions. To this end we present techniques to measure betatron tune, chromaticity, betafunction magnitude/phase, and orbit response matrices all in such a way that no disturbance to the stored beam can be observed by the users of the light source. Examples of measurements for the various categories are compared to established methods, and their use in feedback schemes is discussed.
Fermilab, Batavia
Ionization profile monitors (IPMs) are installed in the Fermilab Booster, Main Injector and Tevatron. They are used routinely for injection matching measurements. For emittance measurements the IPMs have played a secondary role to the Flying Wires, with the exception of the Booster (where it is the only profile diagnostics). As Fermilab is refocusing its attention on the intensity frontier, non-intercepting diagnostics such as IPMs are expected to become even more important. This paper gives an overview of the operational use of IPMs for emittance and injection matching measurements at Fermilab, and summarizes the future plans.
LANL, Los Alamos, New Mexico
A beam position reproducibility measurement was performed using the beam position monitors in the Los Alamos Proton Storage Ring. The purpose of this measurement was to gain a better understanding of the quality, errors, and repeatability associated with such a measurement. Described here is a somewhat detailed understanding of how the beam position monitor measurement is made, and the procedure for this reproducibility experiment. Data and statistical analysis, and the fitting of the turn-by-turn position data are discussed in detail. Also reported are the errors found in the data acquisition, how often the errors occur, how the errors are identified and removed from the dataset, their effect on the quality of the beam position measurement, and scenarios of how these errors manifest in the data acquisition. The resulting conclusions of the repeatability of the beam position measurement is based on the spread of fitting parameters fit to the turn-by-turn beam position data.
SLAC, Menlo Park, California
SSRL designed and built beam position electronics for its SPEAR3 storage ring. We designed the electronics, using digital receiver technology, for highly accurate turn by turn measurements of both the position and arrival time of the beam, allowing us to use this system to measure the betatron and synchrotron tunes of the beam. The dynamic range of the system allows us to measure the properties of the beam at currents ranging from those of single bunch injection to those of the full SPEAR stored beam. This paper discusses the architecture of the electronics, presents their performance specifications, and shows a range of applications of this system for accelerator physics experiments.
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.
CERN, Geneva
The fast beam current transformers (FBCTs) for the Large Hadron Collider (LHC) were designed to provide bunch to bunch and turn by turn intensity measurements. The required bunch to bunch measurements together with a large machine circumference call for stringent control of the transmission bandwidth, droop and DC offsets in the front-end electronics. In addition, two measurement dynamic ranges are needed to achieve the required measurement precision, increasing the complexity of the calibration. This paper reports on the analysis of the measurement and calibration methods, discusses theoretical precision limits and system limitations and provides a comparison of the theoretical results with the real data measured during the LHC start-up.
I-Tech, Solkan
ESRF, Grenoble
The lifetime of the electron beam in a Synchrotron Light Source is an important parameter. Its precise measurement within a short time is an essential tool to evaluate properties and stability of a storage ring. In some cases, for example during short gas outbursts in the UHV vacuum chamber leading to rapid lifetime drops, it can be used as a useful diagnostic tool as well. Traditionally, dedicated PCTs (Parametric Current Transformers) are mostly used for this purpose. The idea to use Libera Brilliance Beam Position Processor instead came after the excellent quality of its sum signal was observed. Moreover, the measurement accuracy is greatly increased by averaging the lifetime measurements of all the individual stations, bearing in mind that there are typically more than hundred BPMs positioned around the ring. First measurements were performed on ESRF, showing very good performance potential. The article discusses the measurements, their results, the comparison with more classical methods, and the implementation of this feature in the Libera Brilliance software.
SLAC, Menlo Park, California
BNL, Upton, Long Island, New York
Life Imaging Technology, Palo Alto, California
For top-up injection it is important to understand the time evolution of the incident charge in the transverse and longitudinal coordinate systems. In SPEAR3, the injection system has a vertically-deflecting Lambertson septum with the injected beam entering ~13mm to the inside. The resulting large-amplitude betatron oscillations give rise to rapid filamentation followed by nominal radiation damping and in some cases non-linear x-y coupling. Similarly, in the longitudinal dimension, a mis-match in beam arrival time or energy can result non-linear beam dynamics and damped synchrotron motion. To the next order, any betatron, bunch length or energy spread mismatch will generate damped ‘quadrupole’ oscillations or even higher-order motion. In this paper we report on measurements of injection beam dynamics in the transverse and longitudinal coordinate systems using a fast-gated, image-intensified CCD camera and a Hamamatsu C5680 streak camera, respectively. The injection beam dynamics are shown to contain relatively complicated evolution in the x-y-z beam distributions that change with injection conditions and storage ring lattice configuration.
CERN, Geneva
The BBQ tune (Q) and chromaticity (Q') diagnostic systems played a crucial role during LHC commissioning, both in establishing circulating beam and for the first ramps. Early on, they allowed identification of issues such as the residual tune stability, beam spectrum interferences and beam-beam effects – all of which may impact beam life times and are therefore being addressed in view of nominal LHC operation. This contribution discusses the initial beam stability in relation to the achieved instrumentation sensitivity, corresponding tune frequency and chromaticity resolution.
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
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.
NSRRC, Hsinchu
Diagnostics of the 1.5 GeV Taiwan Light Source (TLS) has been continue upgraded since it operation started in 1993. BPM electronics and orbit feedback system have been upgrade in 2008. Commercial photon BPM electronics was tested recently. The bunch-by-bunch feedback have been deployed to improve beam stability. These upgrades are contributed to improve beam quality a lots. These efforts will be addressed also.