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Accurate measurements of optics functions, β, α, D, are essential for proper operation of a synchrotron both for machine protection and for performance. β functions can be obtained from different observables: phase and amplitude of the transverse betatron oscillations and change of the tune by modulating the current of quadrupoles (K-modulation). Reconstruction of β function using the betatron phase, in combination with K-modulation, has been the main measurement approach in the LHC IRs. Nonetheless, challenges have appeared in the β calculation using these two techniques when aiming for smaller β^{*}, i.e., β-values at the interaction point (IP) in the LHC and the HL-LHC. The third β measurement technique, based on the beam position monitor (BPM) signal amplitude, has not been used as widely in the LHC as the other methods since it requires accurate BPM gain calibration. This paper presents the development of a technique based on optics measurements to calibrate accurately LHC IR BPMs, allowing to use of the amplitude information in the measurement of IR β functions.

Most contemporary storage rings operate in the multibunch mode. In this case, the transverse dynamics in the presence of feedback may be complicated. Indeed, generally, the amplified signal of beam position monitor kicks all circulating bunches. In this paper, the stability of such system with many degrees of freedom is considered. Damping times are estimated for the simplest cases.

Graphical abstract, A compact beam-position monitor was constructed using a linear contact image sensor attached to a plastic scintillator and tested using a 230 MeV proton beam. The results indicate that the beam position can be obtained in real-time, and the beam position with a precision of up to 0.03 mm. The compactness and high precision of the device hold considerable potential for it to be used as a beam-position monitor and offline, daily quality assurance monitor in hadron therapy. • The method can provide a high precision and high resolution beam position for flash irradiation in particle therapy in real-time. • The method using contact image sensor with scintillator does not require a long focal length for camera and it is free of image distortion. • The method can be integrated into medical particle accelerator for feedback control and daily quality assurance.

Graphical abstract, We introduce a novel technique to implement gate functionality for the beam position monitors (BPM) at the National Synchrotron Light Source II (NSLS-II). The functionality, now implemented in FPGA, allows us to acquire two separated bunch-trains’ synchronized turn-by-turn (TBT) data simultaneously with the NSLS-II in-house developed BPM system. The gated position resolution is improved about 3 times by narrowing the sampling width. Experimentally we demonstrated that the machine lattice could be transparently characterized with the gated TBT data of a short diagnostic bunch-train Cheng et al., 2017; Li et al., 2017. Other applications, for example, precisely characterizing storage ring impedance/wake-field through recording the beam positions of two separated bunch trains has been experimentally demonstrated. • Gated BPM signal processing improves the position resolution. • Transparent lattice measurement using the gate function with diagnostic bunches. • Collective effect study with simultaneous position measurement from two gates.

We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.

Diagnostic systems are key components for all accelerators, and Beam Position Monitor (BPM) systems are one of the primary functional units. Such systems allow us to observe the beam characteristics and hence interpret and adjust the beam parameters to achieve the required parameter range. This study aims to specify BPM parameters like antenna radius, capacitance, signal-to-noise ratio (SNR), etc. for Turkish Accelerator and Radiation Laboratory in Ankara (TARLA). Searching optimal values for such parameters is conventionally performed using methods including Finite Element Methods (FEM) or analytical approximation. Here, Multiple Objective Evolutionary Algorithms (MOEA) were employed as an alternative. We aimed to obtain a wide range of available results for possible production constraints. Considering TARLA beam parameters, button-type BPMs can be employed as diagnostic tools due to their low cost and simple mechanical structure. SNR levels of 20–40[Formula: see text]dB were achieved using antennas with radius parameters of 3–10[Formula: see text]mm. It is known that these SNR levels are in the acceptable range for the read-out electronic system.

A system has been developed to measure the vertical position and angle of the electron beam at a single location from a synchrotron source. The system uses a monochromator tuned to the absorption edge of a contrast material and has a sensitivity comparable with other beam position monitors., The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered in position and angle at the source point. The results are comparable with other methods of beam position measurement and indicate that such a system is feasible in situations where part of the synchrotron beam can be used for the phase-space measurement.

Simultaneous photon beam position and intensity monitoring is becoming of increasing importance for new generation synchrotron radiation sources and free electron lasers (FEL). Thus, novel concepts of beam diagnostics are required in order to keep such beams under control. From this perspective diamond is a promising material for the production of semitransparent in situ photon beam monitors, which can withstand the high dose rates occurring in such radiation facilities. Here, we report on the development of freestanding, single-crystal chemical-vapor-deposited diamond detectors with segmented electrodes. Due to their direct, low-energy band gap, InGaAs quantum well devices operated at room temperature may also be used as fast detectors for photons ranging from visible to X-ray. These features are valuable in low-energy and time-resolved FEL applications. In particular, a novel segmented InGaAs/InAlAs device has been developed and will be discussed. Dedicated measurements carried out on both these devices at the Elettra Synchrotron show their capability to monitor the position and the intensity of the photon beam with bunch-by-bunch temporal performances. Furthermore, preliminary tests have been performed on diamond detectors at the Fermi EEL, extracting quantitative intensity and position information for 100-fs-wide FEL pulses with a photon energy of 28.8 eV. (C) 2013 Elsevier B.V. All rights reserved

This paper summarizes the results of the study of a bunch length monitor based on the button BPM (Beam Position Monitor). The monitor consists of a BPM installed on the beam pipe and a spectrum analyzer. We use the button-BPM's button pickups as the electrodes to pick up the signal. The bunch length can be derived from the spectrum of the beam-induced signal got by the spectrum analyzer. We show the theoretical results and the simulations performed by CST

The Touschek lifetime scales with bunch current, beam vertical emittance, bunch length and momentum acceptance, as derived in previous chapter: $$\begin{aligned} \tau _t \propto \frac{\sqrt{\varepsilon _y} \sigma _z}{I_b} \delta _{acc}^3 \end{aligned}$$ where \(\varepsilon _y\) is the vertical emittance, \(\sigma _z\) is the root mean square bunch length, \(I_b\) is the bunch current and \(\delta _{acc}\) is the momentum acceptance. In this chapter, the measurements of all the relevant parameters for the Touschek lifetime are discussed.

A 20-MeV proton accelerator has been developed and tested at the Korea Atomic Energy Institute (KAERI) by the Proton Engineering Frontier Project (PEFP). Beam phase was measured at the end of the 20-MeV accelerator by using the beam position monitor (BPM) signal. The beam current and phase were measured by changing the relative RF phase between the 3-MeV radio frequency quadrupole (RFQ) and the 20-MeV drift; tube linac (DTL), and the results were compared with those simulated by using the PARMILA code. In tins paper, the beam phase measurement results are presented, and the phase scan results based on the normal operating condition are compared with the simulation results.

A non-destructive large-aperture beam position monitor has been developed to measure the beam position of the 150 MeV Fixed Field Alternating Gradient (FFAG) accelerator at Center for Accelerator and Beam Applied Science of Kyushu University. The results of the performance test of a prototype of the new beam position monitor with multi-electrodes are described.��

A prototype of resistive beam position monitor was designed and built for Mini-LIA. The design parameters and bench test results are presented. A beam displacement nearly 1 mm off-axis can be observed. The relationship between the signal amplitude and decay time constant to current rising time was studied.

The work for this thesis is in line with the field of Instrumentation for Particle Accelerators, so called Beam Diagnostics. It is presented the development of a series of electro-mechanical devices called Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM). A full set of 17 BPM units (16 + 1 spare), named BPS units, were built and installed into the Test Beam Line (TBL), an electron beam decelerator, of the 3rd CLIC Test Facility (CTF3) at CERN ¿European Organization for the Nuclear Research¿. The CTF3, built at CERN by an international collaboration, was meant to demonstrate the technical feasibility of the key concepts for CLIC ¿Compact Linear Collider¿ as a future linear collider based on the novel two-beam acceleration scheme, and in order to achieve the next energy frontier for a lepton collider in theMulti-TeV scale. Modern particle accelerators and in particular future colliders like CLIC requires an extreme alignment and stabilization of the beam in order to enhance its quality, which rely heavily on a beam based alignment techniques. Here the BPMs, like the BPS-IPU, play an important role providing the beam position with precision and high resolution, besides a beam current measurement in the case of the BPS, along the beam lines. The BPS project carried out at IFIC was mainly developed in two phases: prototyping and series production and test for the TBL. In the first project phase two fully functional BPS prototypes were constructed, focusing in this thesis work on the electronic design of the BPS on-board PCBs (Printed Circuit Boards) which are based on transformers for the current sensing and beam position measurement. Furthermore, it is described the monitor mechanical design with emphasis on all the parts directly involved in its electromagnetic functioning, as a result of the coupling of the EM fields generated by the beam with those parts. For that, it was studied its operational parameters, according the TBL specifications, and it was also simulated a new circuital model reproducing the BPS monitor frequency response for its operational bandwidth (1kHz-100MHz). These prototypes were initially tested in the laboratories of the BI-PI section¿Beam Instrumentation - Position and Intensity¿ at CERN. In the second project phase the BPS monitor series, which were built based on the experience acquired during the prototyping phase, the work was focused on the realization of the characterization tests to measure the main operational parameters of each series monitor, for which it was designed and constructed two test benches with different purposes and frequency regions. The first one is designed to work in the low frequency region, between 1kHz-100MHz, in the time scale of the electron beam pulse with a repetition period of 1s and an approximate duration of 140ns. This kind of test setups called Wire Test-bench are commonly used in the accelerators instrumentation field in order to determine the characteristic parameters of a BPM (or pick-up) like its linearity and precision in the position measurement, and also its frequency response (bandwidth). This is done by emulating a low current intensity beam with a stretched wire carrying a current signals which can be precisely positioned with respect the device under test. This test bench was specifically made for the BPS monitor and conceived to perform the measurement data acquisition in an automated way, managing the measurement equipment and the wire positioning motors controller from a PC workstation. Each one of the BPS monitors series were characterized by using this system at the IFIC labs, and the test results and analysis are presented in this work. On the other hand, the high frequency tests, above the X band in the microwave spectrum and at the time scale of the micro-bunch pulses with a bunching period of 83ps (12GHz) inside a long 140ns pulse, were performed in order to measure the longitudinal impedance of the BPS monitor. This must be low enough in order to minimize the perturbations on the beam produced at crossing the monitor, which affects to its stability during the propagation along the line. For that, it was built the high frequency test bench as a coaxial waveguide structure of 24mm diameter matched at 50¿ and with a bandwidth from 18MHz to 30GHz, which was previously simulated, and having room in the middle to place the BPS as the device under test. This high frequency test bench is able to reproduce the TEM (Transversal Electro-Magnetic) propagative modes corresponding to an ultra-relativistic electron beam of 12GHz bunching frequency, so that the Scattering parameters can be measured to obtain the longitudinal impedance of the BPS in the frequency range of interest. Finally, it is also presented the results of the beam test made in the TBL line, with beam currents from 3.5A to 13A (max. available at the moment of the test). In order to determine the minimum resolution attainable by a BPS monitor in the measurement of the beam position, being the device figure of merit, with a resolution goal of 5¿m at maximum beam current of 28A according to the TBL specifications., García Garrigós, JJ. (2013). Development of the Beam Position Monitors for the Diagnostics of the Test Beam Line in the CTF3 at CERN [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/34327., Alfresco

The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, albeit with a slightly lower precision than requested, giving a promising new beam position monitoring system. They work for the full intensity range and a single bunch resolution is achieved. Functionality is also shown with backscattering from dense targets.

Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

At present, the beam-based alignment of the LHC collimators is performed by touching the beam halo with both jaws of each collimator. This method requires dedicated fills at low intensities that are done infrequently and makes this procedure time consuming. This limits the operational flexibility, in particular in the case of changes of optics and orbit configuration in the experimental regions. The performance of the LHC collimation system relies on the machine reproducibility and regular loss maps to validate the settings of the collimator jaws. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with jaw-integrated Beam Position Monitors (BPMs) was proposed and successfully tested with a prototype (mock-up) collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper, the results of these experiments are discussed. The non-linear response of the BPMs is compared to the predictions from electromagnetic simulations. Finally, the measured alignment accuracy is compared to the one achieved with the present collimators in the LHC., peer-reviewed

Model-independent analysis (MIA) methods are generally useful for analysing complex systems in which relationships between the observables are non-trivial and noise is present. Principal Component Analysis (PCA) is one of MIA methods allowing to isolate components in the input data graded to their contribution to the variability of the data. In this publication we show how the PCA can be applied to digitised signals obtained from a cavity beam position monitor (CBPM) system on the example of a 3-cavity test system installed at the Accelerator Test Facility 2 (ATF2) at KEK in Japan. We demonstrate that the PCA based method can be used to extract beam position information, and matches conventional techniques in terms of performance, while requiring considerably less settings and data for calibration.

A beam position monitor using higher order mode (HOM) couplers is proposed. This has the possibility to detect beam positions through superconducting accelerators in long cryostats where normal beam position monitors cannot be installed. The primary measurement was done to show the correlation between the beam position and the HOM power.

International audience; Diamond is a promising material for the production of semitransparent in situ photon beam monitors which can withstand the high dose rates occurring in new generation synchrotron radiation storage rings and in free electron lasers. We report on the development of a 500 mu m thick freestanding, single crystal chemical vapor deposited diamond detector with segmented electrodes. Performances in both low and radio frequency beam monitoring are presented as well. By using charge integration techniques at a frame rate of 6.5 kHz in combination with a needle synchrotron radiation beam and mesh scans, the inhomogeneity of the sensor was found to be of the order of 2%; with a measured electronics noise of 2 pA / root Hz a 0.05% relative precision in the intensity measurements (at 1 mu A) and a 0.1 mu m resolution in the position encoding have been estimated. Moreover, the high electron-hole mobility of diamond compared with other active materials enables very fast charge collection characterized by rise-times below 1 ns; this allowed us to utilize single pulse integration to simultaneously detect the intensity and the position of each synchrotron radiation photon bunch generated by a bending magnet

This paper describes the development of a digital-based Beam Position System which was designed, developed, and adapted for the Tevatron during Collider Run II., Comment: 20 pp

Recent progress in the development of a beam position monitor system (BPM), based on the log‐ratio technique, is described in this paper. A complete electronic analysis is presented, showing linearity, dynamic range, noise, RF burst response, and temperature dependence. A calibration technique has been developed, which corrects the errors due to mismatched channels and electronics drift. This technique is particularly effective because of the log‐ratio property for beam position monitoring. This circuit is the most likely candidate for beam position monitor electronics at the SSC.

Multiturn (or turn-by-turn) data acquisition has proven to be a new source of direct measurements for Twiss parameters in storage rings. On the other hand, closed-orbit measurements are a long-known tool for analyzing closed-orbit perturbations with conventional beam position monitor (BPM) systems and are necessarily available at every storage ring. This paper aims at combining the advantages of multiturn measurements and closed-orbit data. We show that only two multiturn BPMs and four correctors in one localized drift space in the storage ring (diagnostic drift) are sufficient for model-independent and absolute measuring of $\ensuremath{\beta}$ and $\ensuremath{\varphi}$ functions at all BPMs, including the conventional ones, instead of requiring all BPMs being equipped with multiturn electronics.

The superconducting CW linac of the ELBE facility produces an electron beam up to 40 MeV and 1 mA average current. The beam is used to drive two IR FELs and target stations for production of bremsstrahlung, neutrons, and positrons. An upgrade of the ELBE facility is ongoing which includes an increase of beam current as well as new experimental opportunities such as the production of broadband THz radiation and the interaction of electrons with high power laser beams. The high beam power requires a fast and safe machine protection system. It was found that a continuous beam loss of about 10 µA or a total beam loss for longer than 2 ms produce damage. The beam loss at ELBE is monitored by two systems: beam loss monitors measuring the radiation in cable-like ionization chambers along the beamline, and beam current difference measurement system based on stripe line beam position monitors.

A new method that explores turn-by-turn beam position monitor (BPM) data to calibrate lattice models of accelerators is proposed. The turn-by-turn phase space coordinates at one location of the ring are first established using data from two BPMs separated by a simple section with a known transfer matrix, such as a drift space. The phase space coordinates are then tracked with the model to predict positions at other BPMs, which can be compared to measurements. The model is adjusted to minimize the difference between the measured and predicted orbit data. BPM gains and rolls are included as fitting variables. This technique can be applied to either the entire or a section of the ring. We have tested the method experimentally on a part of the SPEAR3 ring.

Accurate and reliable beam position measurements are required to commission and operate the DARHT II Accelerator. The beam position monitor (BPM) system developed for use on the DARHT accelerator consists of 31 electro-magnetic detector assemblies, a computer network based data acquisition system, and analysis software. During each "shot" each BPM uses arrays of b-dot detectors to intercept the electron beam's changing magnetic field. The detector outputs are individually recorded. Post shot analysis of the data provides the beam current and position information. This paper will provide an overview of the system and give details regarding its performance.

The European XFEL will be a free electron laser based on self amplified spontaneous emission in the X-ray regime. The FEL is driven by a superconducting 17.5 GeV linear accelerator, followed by 5 separate undulators both for SASE FEL radiation and incoherent radiation. Start of operation is foreseen for 2013. This paper presents the layout of the European XFEL, with an emphasis on beam dynamics issues.

The beam commissioning of J-PARC LINAC has been started in November 2006. Beam position monitors (BPMs) which had been calibrated on the bench setup with a scanning wire, take beam-based-calibration method in order to enable the beam to pass at the centre of a quadrupole magnet (Q-magnet). In this presentation, the installed BPMs and their calibration methods are described.

Orbit response matrix (ORM) measurements are used in many circular accelerators to measure and correct gradient and optics errors, beam position monitor (BPM) gain errors, and dipole corrector gain errors [1]. Here we report results of numerical studies of the RHIC FY06 polarized proton injection and storage lattices to evaluate the feasibility of RHIC ORM analysis, and quantify the effect of random errors (including BPM noise) on ORM analysis of the RHIC lattice.

To take advantage of the very low source emittance of third generation radiation sources high-resolution in situ X-ray beam monitors are required in order to keep the X-ray beam focussed and incident on the sample. We present a compact device based on a linear photodiode array. It consists of relatively few diodes that measure the spatially resolved scattered X-rays from a thin polymer foil placed in the beam path. The device is vacuum compatible, inexpensive and radiation hard. The scattered X-rays are incident on a strip of photodiodes that are connected to a dedicated multi-channel charge-sensitive read-out chip. Test experiments performed at the European Synchrotron Radiation Facility (ESRF) show, that even at a relatively low-intensity bending magnet beam line, X-ray beam position and profiles are obtained extremely fast and precise.

The offset beam from the axis induces the HOMs in the cavities. These HOMs in superconducting cavities are usually damped by HOM couplers to suppress the beam instability. The induced HOM field of dipole mode is proportional to the beam offset and can be used to measure the beam position inside the cavity. Measuring the HOM power by scanning the beam permits to estimate the beam position using a known function of the HOM power. The steering magnet was installed to the JAEA superconducting ERL-FEL to vary the beam position. The beam position in the cavity was estimated with the measured HOM power from the HOM coupler.

The LHC, presently being built at CERN, is the first proton collider that requires a continuous orbit control for safe and reliable machine operation. A realistic test of the orbit feedback system was performed in 2004 using already-present LHC instrumentation and infrastructure on a 270GeV coasting beam in the Super-Proton-Synchrotron. It has been demonstrated that the chosen feedback architecture can stabilise the beam better than 10 micrometres and is essentially limited by the noise of the beam position monitor and the bandwidth of the corrector magnets. The achieved orbit stability is comparable to those found at modern light sources and gives enough operational margin with respect to the requirements of the LHC Cleaning System (70 µ m). Estimates for the longterm drifts and achievable stability will be presented based on the experimental results.

Independent position measurement of the counter-circulating proton and antiproton beams in the Tevatron, never supported by the original Tevatron Beam Position Monitor (BPM) system, presents a challenge to upgrading that system. This paper discusses the possibilities and complications of using time separation of proton and antiproton signals at the numerous BPM locations and for the dynamic Tevatron operating conditions. Results of measurements using one such method are presented.

After removal of gain‐switching relays in the signal paths of RHIC beam position monitor (BPM) electronics, we are able to calibrate the electronics with very good reproducibility. An improved calibration method has been developed to calibrate the BPM electronics and remove all error due to variation of electronic components. In the past, different results were obtained when using the on‐board calibration pulser or an externally generated calibration signal. An attempt has been made to characterize the difference between the internal and external signal paths, which will be the basis for a new version of software that will ensure reliable, internal, in‐situ calibration. This paper will describe the hardware and software involved in the calibration of the BPM electronics and present results. It will also discuss the limitations and specifications of calibration.

We present an improved system for orbit and betatron phase measurement utilizing nonlinear models of beam position monitor (BPM) pickup response. We first describe the calculation of the BPM pickup signals as nonlinear functions of beam position using Greens reciprocity theorem with a two-dimensional formalism. We then describe the incorporation of these calculations into our beam position measurements by inverting the nonlinear functions, giving us beam position as a function of the pickup signals, and how this is also used to improve our calculation of the betatron phase advance. Measurements are presented comparing this system with the linearized pickup response used historically at CESR.

Recently, resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of beam position monitor (BPM) data. Based on these measurements a new analysis has been derived to extract truly local observables from BPM data. These local observables are called local resonance terms since they share some similarities with the global resonance terms. In this paper we derive these local terms analytically and present experimental measurements of sextupolar global and local resonance terms in RHIC. Nondestructive measurements of these terms using ac dipoles are also presented.

Horizontal orbit errors at the sextupoles in the Advanced Photon Source (APS) storage ring can cause changes in tune and modulation of the beta functions around the ring. To determine the significance of these effects requires knowing the orbit relative to the magnetic center of the sextupoles. The method considered here to determine the horizontal beam position in a given sextupole is to measure the tune shift caused by a change in the sextupole strength. The tune shift and a beta function for the same plane uniquely determine the horizontal beam position in the sextupole. The beta function at the sextupole was determined by propagating the beta functions measured at nearby quadrupoles to the sextupole location. This method was used to measure the sextupole magnetic center offset relative to an adjacent beam position monitor (BPM) at a number of sextupole locations. We report on the successes and problems of the method as well as an alternate method.

The beam position monitor system (BPM) of NSRL electron storage ring have a resolution of 10 microns with an accuracy of 50 microns, which is adequate fix beam position measurement and the closed orbit correction. The paper describes both of the BPM system and the closed orbit measurement.

The Fermilab recycler ring, designed and built as an 8-GeV anti-proton storage ring, is at the final stage of its commissioning. Once integrated into the accelerator complex it is expected to help achieve the luminosity goal of Run II at Fermilab. The recycler ring is made up mostly of combined function magnets with a substantial sextupole component. Any orbit error could cause higher order feed-down and potentially change the machine. Lattice function measurements had been done at various stages of the machine and the results is presented here

For Collider physics the parameters Luminosity u and total center-of-mass energy √s largely characterize the machine performance and the physics reach.

A working prototype of beam position monitor (BPM) electronics, based on the log-ratio technique is described in this paper. Results of a test performed at the Fermilab Booster, comparing the existing Fermilab BPM system are also presented. A calibration technique has been used which corrects errors due to mismatched channels and electronics drift. The results are compared with bench measurements on the prototype circuit. >

The AmPS (Amsterdam Pulse Stretcher) is a 900-MeV electron storage and stretcher ring. Its construction started early 1991. A fast-response, high-resolution stripline-type beam position monitor has been developed for the ring. The monitor has a quasi-elliptic cross section. Its sensing strips have a length of lambda /4; the operating frequency is 2856 MHz. The mechanical construction, the matching of the output ports, and the online calibration system are described. The results of bench measurements as well as measurements with a 500-MeV beam are also presented. >

The R&D of single-pass beam position monitor is being carried out at SOR-RING, a 500-MeV electron storage ring. The bunch signals from four button electrodes are directly fed into a 4-channel digital oscilloscope through semi-rigid cables. The digitized data are sent to a workstation for the beam position calculation. The relative accuracy much less than 0.1 mm has been obtained with this system.

The beam position monitor (BPM) system is of most importance in a light source. The capability of the BPM depends on the resolution of the system. The traditional standard deviation on the raw data method merely gives the upper limit of the resolution. Principal component analysis (PCA) had been introduced in the accelerator physics and it could be used to get rid of the actual signals. Beam related informations were extracted before the evaluation of the BPM performance. A series of studies had been made in Shanghai Synchrotron Radiation Facility (SSRF) and PCA was proved as an effective and robust method in the performance evaluations of our BPM system., 6 pages, 12 figures

Scope of this thesis is the evaluation of the influence of the relative and absolute accuracy of the beam position measuring system on the performance of DELTA, a third generation synchrotron radiation source. Emphasis is put on the beam based calibration system, developed for DELTA, which gives an absolute accuracy of the beam position measurement with respect to the magnetic axis of the quadrupole magnets of 20um. Furthermore for beam position monitors with capacitive pick-up electrodes an analytical solution for the determination of the signal function of a beam with gaussian charge distribution in relation to the signal function of a pencil beam is given. The influence on the determination of the beam position is evaluated and the possibility to develop an emittance measuring system, based on these effects, is discussed.

The development at the present MAX I ring concerning a new beam position monitor system, enhanced injection efficiency, harmonic generation of coherent radiation, the suppression of longitudinal instabilities and some development work on the 100 MeV race-track microtron to increase the bunch current is presented. The lattice and design philosophy of the 1.5 GeV MAX II third generation synchrotron light source currently being built at MAX-lab are also discussed.

We present the results from two studies of the time stability between the mechanical center of a beam position monitor (BPM) and its electrical/electronic center. In the first study, a group of 93 BPM processors was calibrated via a test pulse generator once per hour, in order to measure the contribution of the readout electronics to offset drifts. In the second study, a triplet of stripline BPMs in the Final Focus Test Beam, separated only by drift spaces, was read out every six minutes during one week of beam operation. In both cases offset stability was observed to be on the order of microns over time spans ranging from hours to days, although during the beam study much worse performance was also observed. Implications for the BPM system of future linear collider systems are discussed.

We have developed an S-band cavity Beam Position Monitor (BPM) in order to measure the position of an electron beam in the final focus area at ATF2, which is the test facility for the final focus design for the International Linear Collider (ILC). The lattice of the ILC Beam Delivery System (BDS) has been modified, requiring a larger physical aperture of 40 mm in the final focus area. The beam orbit measurement in this area is now covered with high resolution S-Band cavity BPMs. In this paper we summarize the design of the cavity BPM and the first experimental results. The calibration slopes were measured as 0.87 counts/?m in the x-coordinate direction and 1.16 counts/?m in the y-coordinate direction.

Design of the SSC collider ring standard spool piece nears completion, and two production prototype units are being fabricated. Spool pieces are complex cryogenic components of the SSC collider ring which provide interface and/or control of cryogens, vacuum, power, instrumentation, and quench protection and also house the corrector magnets and the beam position monitor. The use of 3D animation in conjunction with simulation in capacity planning, scheduling, and resource utilization and management for production will be discussed.

This article is intended to provide an introduction to the beam instrumentation systems and the precision timing system of the SSC Laboratory. The Beam Instrumentation Department of the SSC Accelerator Systems Division is responsible for the design of these systems for the Collider rings and the injector accelerators. Status and plans are briefly described.