The Beam Loss Monitors (BLM) are designed to measure the position and amount of beam loss in accelerators. In this article, we have studied the 3 GeV electron losses in the storage ring and secondary particles from the losses on the beam pipe. We have compared ionization chamber, NaI and Si radiation detectors as BLM and selected Si detector for further studies. We have calculated electron deflection angle due to magnetic field mismatches in dipole magnets, quadrupoles and sextupoles and assumed that electron beam is deflected and hit the beam pipe with the angle of 3 degrees with respect to the beam axis. The number and energy of photons and secondary particles on beam pipe and in Si detector are calculated by the MCNP code and reported in this paper.
Hefei Light Source (HLS) is being upgraded to HLS II. Its emittance will be much lower than before, therefore the Touschek scattering will increase significantly and become the dominant factor of beam loss. So it is necessary to build a new beam loss monitoring (BLM) system differed from the old one to obtain the quantity and position information of lost electrons. This information is useful in the commissioning, troubleshooting and beam lifetime studying for HLS II. This paper analyzes the distribution features of different kinds of lost electrons, introduces the new machine's operation param…
The Main Injector (MI) was commissioned using data acquisition systems developed for the Fermilab Main Ring in the 1980s. New VME-based instrumentation was commissioned in 2006 for beam loss monitors (BLM)[2], which provided a more systematic study of the machine and improved displays of routine operation. However, current projects are demanding more data and at a faster rate from this aging hardware. One such project, Real-time Edge AI for Distributed Systems (READS), requires the high-frequency, low-latency collection of synchronized BLM readings from around the approximately two-mile accele…
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 demon…
We introduce a new application of measuring symplectic generators to characterize and control the linear betatron coupling in storage rings. From synchronized and consecutive BPM (Beam Position Monitor) turn-by-turn (TbT) readings, symplectic Lie generators describing the coupled linear dynamics are extracted. Four plane-crossing terms in the generators directly characterize the coupling between the horizontal and the vertical planes. Coupling control can be accomplished by utilizing the dependency of these plane-crossing terms on skew quadrupoles. The method has been successfully demonstrated…
The piece of NESTOR vacuum chamber with the ceramic insertion for DC-monitor and RF-shields was simulated by using both transient and wake field solvers of CST Studio Suite. For a 6 mm gap between two RF-shields the contributions of the assembly considered to the longitudinal broadband (BB) impedance Z/n and the loss factor kloss are 0.71 Ohm and 0.21 V/pC, correspondingly. These estimates are the second largest after those of the RF-cavity that were obtained till now for the NESTOR ring components. Contributions from a beam position monitor (BPM) are also obtained by simulation and compared w…
In this paper, beam diagnostic and monitoring tools developed by the MAX IV Operations Group are discussed. In particular, new beam position monitoring and accelerator tunes visualization software tools, as well as tools that directly influence the beam quality and stability are introduced. An availability and downtime monitoring application is also presented.
The Cornell Electron-positron Storage Ring (CESR) has been converted from a High Energy Physics electron-positron collider to operate as a dedicated synchrotron light source for the Cornell High Energy Synchrotron Source (CHESS) and to conduct accelerator physics research as a test accelerator, capable of studying topics relevant to future damping rings, colliders and light sources. Some of the specific topics that were targeted for the initial phase of operation of the storage ring in this mode, labeled CesrTA (CESR as a Test Accelerator), included 1) tuning techniques to produce low emittanc…
In storage rings, horizontal dispersion in the rf cavities introduces horizontal-longitudinal (xz) coupling, contributing to beam tilt in the xz plane. This coupling can be characterized by a "crabbing" dispersion term ζa that appears in the normal mode decomposition of the 1-turn transfer matrix. ζa is proportional to the rf cavity voltage and the horizontal dispersion in the cavity. We report experiments at the Cornell Electron Storage Ring Test Accelerator (CesrTA) where xz coupling was explored using three lattices with distinct crabbing properties. We characterize the xz coupling for each…
Beam lifetime in storage rings and colliders is affected by, among other effects, lattice nonlinearities. Their control are of great benefit to the dynamic aperture of an accelerator, whose enlargement leads in general to more efficient injection and longer lifetime. This article describes a procedure to evaluate and correct unwanted nonlinearities by using turn-by-turn beam position monitor data, which is an evolution of previous works on the resonance driving terms (RDTs). Effective sextupole magnetic errors and tilts at the ESRF electron storage ring are evaluated and corrected (when possib…
Louisiana State University Center for Advanced Microstructures and Devices (CAMD) began a control system upgrade project in early 1997. At the time, the storage ring was controlled by a VAX/VMS system, primarily using CAMAC for I/O. The injector Linac was controlled by a separate VME/OS/9 system using custom I/O components. The storage ring control system has been replaced with a PC/Linux based system, utilizing the existing CAMAC subsystem [1]. In an effort to both migrate channels away from CAMAC, and integrate the Linac controls with the storage ring controls, a design for upgrades utilizin…
We report on an injection feedback scheme for the ThomX storage ring project. ThomX is a 50-MeV-electron accelerator prototype which will use Compton backscattering in a storage ring to generate a high flux of hard X-rays. Given the slow beam damping (in the ring), the injection must be performed with high accuracy to avoid large betatron oscillations. A homemade analytic code is used to compute the corrections that need to be applied before the beam injection to achieve a beam position accuracy of a few hundred micrometers in the first beam position monitors (BPMs). In order to do so the code…
In the storage ring of PLS-II, we reduced mechanical displacement of electron beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The orbit feedback system intends that the electron beam pass through the center of the BPM, so to provide stable photon beam into beamlines the BPM pickup itself must be stable to sub-micrometer precision. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by unintended beam abort. We reduced this deformation by improving the vacuum chamber support and …
The development of fast detection methods for comprehensive monitoring of electron bunches is a prerequisite to gain comprehensive control over the synchrontron emission in storage rings with their MHz repetition rate. Here, we present a proof-of-principle experiment with at detailed description of our implementation to detect the longitudinal electron bunch profiles via single-shot, near-field electro-optical sampling at the Karlsruhe Research Accelerator (KARA). Our experiment is equipped with an ultra-fast line array camera providing a high-throughput MHz data stream. We characterize statis…
The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and gamma-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electr…
Precision searches for the electric dipole moment of protons in storage ring experiments call for beam-position monitoring in the picometer range. We present the relevant fully quantum mechanical derivation of radiofrequency-driven collective oscillations of a beam in a storage ring.
A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 um can be measured with a resolution of approximately 5 um. To measure larger beam size (> 500 um), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the pi-polarized co…
With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring's beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their des…
In 2008 the Cornell Electron/Positron Storage Ring (CESR) was reconfigured from an electron/positron collider to serve as a testbed for the International Linear Collider (ILC) damping rings. One of the primary goals of the CESR Test Accelerator (CesrTA) project is to develop a fast low-emittance tuning method which scales well to large rings such as the ILC damping rings, and routinely achieves a vertical emittance of order 10 pm at 2.085 GeV. This paper discusses the tuning methods developed at CesrTA to achieve low-emittance conditions. One iteration of beam-based measurement and correction …
Position sensitive beam monitors are indispensable for the beam diagnostics in storage rings. Apart from their applications in the measurements of beam parameters, they can be used in non-destructive in-ring decay studies of radioactive ion beams as well as enhancing precision in the isochronous mass measurement technique. In this work, we introduce a novel approach based on cavities with elliptical cross-section, in order to compensate for existing limitations in ion storage rings. The design is aimed primarily for future heavy ion storage rings of the FAIR project. The conceptual design is d…
The analysis of beamstrahlung radiation, emitted from a beam of charged particles due to the electromagnetic interaction with a second beam of charged particles, provides a diagnostic tool that can be used to monitor beam-beam collisions in a $e^{+}e^{-}$ storage ring. In this paper we show that the beamstrahlung time profile is related to the timing of the collisions and the length of the beams, and how its measurement can be used to monitor and optimize collisions at the interaction point of the SuperKEKB collider. To measure the time dependence of beamstrahlung, we describe a method based o…
Structural symmetries in the storage ring of synchrotrons are intentionally created during the design phase of the magnetic lattices, but they are not considered in the design of control algorithms that stabilize the beam of accelerated particles. The choice of control algorithm, however, is limited by the speed requirements of the synchrotron. Standard control algorithms for synchrotrons are based on a singular value decomposition (SVD) of the orbit response matrix. SVD controllers neither exploit the structural symmetries nor exhibit any speed advantages. Based on the periodicity and the ref…
The Storage Ring EDM Collaboration is completing a comprehensive proposal to DOE for a sensitive proton EDM experiment at the 10-29e\cdot cm level. This involves building an electric ring of radius R~40 m, with bending provided by stainless steel plates separated by 3 cm gap, providing an electric field of 10 MV/m. This ring can store protons of 0.7 GeV/c momentum, also known as "magic" due to the unique property that the spin and momentum vectors precess at the same rate in any electric field. If the spin is kept longitudinal for most of the duration of the storage time, the radial E-field ac…
We describe the design and performance of optical elements for an x-ray beam size monitor (xBSM), a device measuring $e^+$ and $e^-$ beam sizes in the CESR-TA storage ring. The device can measure vertical beam sizes of $10-100~μ$m on a turn-by-turn, bunch-by-bunch basis at $e^\pm$ beam energies of $\sim2-5~$GeV. X-rays produced by a hard-bend magnet pass through a single- or multiple-slit (coded aperture) optical element onto a detector. The coded aperture slit pattern and thickness of masking material forming that pattern can both be tuned for optimal resolving power. We describe several such…
