JASRI/SPring-8, Hyogo-ken
KEK, Ibaraki
MHI, Tokyo
Mitsubishi Heavy Industries Ltd. (MHI), Takasago
We have been developing a system to generate a short pulse X-ray using crab cavities at SPring-8 Storage Ring. The ring holds 30-m long straight sections and the vertical beam size at the center of the straight sections is 6.5 micrometers in standard deviation. If we install four superconducting crab cavities and a mini-pole undulator in one of the straight sections, we can convert the time distribution of the electron bunch into the spatial distribution. After slicing the emitted photons with vertical slits, we can obtain a sub-picosecond X-ray pulse. In this scheme, the maximum repetition rate of the short pulse X-ray is the same as the acceleration frequency of the ring (508MHz) and user experiments at other beam-lines are not disturbed by this short pulse generation. We are planning to install KEKB type crab cavities as vertical deflectors. Phase fluctuation among crab cavities must be reduced less than 14 mdeg in order to avoid residual deflection in the vertical direction. In this paper, we report an overview of the short pulse generation scheme and topics of hardware development for stabilization of the RF phase fluctuation.
NSC/KIPT, Kharkov
KEK, Ibaraki
Nuclear resonance fluorescence (NRF) is the one of the most promising methods of the nuclear waste management and of the modern technologies of the nonproliferation of nuclear weapons. There are a few proposals of the usage of NRF *,**. Yet linac and energy recovery linac are suggested as the electron source for the Compton scattering (CS) of the laser photons. The storage ring is capable to produce sufficiently higher beam intensity and is more effective since the electrons interact with the laser pulse many times. The storage ring with the electron energy from 240 to 530 MeV is proposed for the CS of 1.16 eV laser photons in the report. Maximal energy of the scattered gamma rays lies within range from 1 MeV to 5 MeV. It allows detecting of practically any isotope in analyzed objects. The specificity of the proposed storage ring is usage of the crab-crossing of the electron and laser beams. Due to crab-crossing we expect to obtain the gamma beam intensity approximately 5*1013 gammas/s for laser flash energy 5 mJ stored in the optical cavity. Both electron beam and gamma beam parameters are studied analytically and by simulation of the CS in the designed ring lattice.
* J. Pruet et al. Detecting clandestine material with nuclear resonance fluorescence. J. Appl. Phys., 99, 123102-1-11 (2006).
** R. Hajima et al. J. Nucl. Sci. Tech., vol. 45, pp. 441-451, 2008.
FEL/Duke University, Durham, North Carolina
SLAC, Menlo Park, California
USTC/NSRL, Hefei, Anhui
Touschek lifetime of an electron beam in a storage ring depends on the beam polarization through the intrabeam scattering effect. Consequently, the electron beam polarization can be determined by comparing the measured Touschek lifetime of a polarized beam and an unpolarized beam. In this paper, we report a systematic experimental procedure to study the radiative polarization of a stored electron beam. Based upon this technique, we have successfully observed the polarization build-up of a 1.15 GeV electron beam in the Duke storage ring. Using the Touchek lifetime data, we are able to determine the equilibrium degree of the electron beam polarization and the time constant for the polarization build-up process.
NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
A multi-element octupole-base corrector magnet is designed and fabricated. The new corrector magnet will be installed in the electron storage ring NewSUBARU in place of vertical steering (skew dipole) magnets. It has coil windings to produce skew quadrupole, skew sextupole, normal octupole, and the skew dipole field. The skew dipole element is used to achieve vertical steering. The skew quadrupole and the skew sextupole elements are for the resonance correction. The normal octupole element is used to control the higher order dispersion function and the higher order momentum compaction factor. In this design the main coil is wound around the return yoke instead of the pole. We expect improvement of the beam lifetime and injection efficiency during normal operation as well as improved isochronism during extreme quasi-isochronous operation. In designing the magnet, careful consideration is given to field interference caused by a neighboring magnet, set close to the corrector magnet of comparable yoke and bore diameter dimensions. The magnetic field with field interference is calculated using OPERA-3D.
NSRRC, Hsinchu
The free space between magnets of TPS storage ring is very tight, especially the space between quadrupole and sextupole magnets. The minimum space between the yoke of quadrupole and sextupole is about 150mm, and the space between coils is only 10mm. In this case, the significant magnetic field distortions could have an impact on the performance of machine. Two magnets simulation compare to the individual magnet were performed in TOSCA 3D model. The crosstalk effect shows that the sextupole component increases from 0.0004% to 0.04% in the quadrupole magnet and the quadrupole component increases from 0.0008% to 0.06% in the sextupole magnet. We discuss this crosstalk effect and how to decrease the effect with appropriate shielding.
Fermilab, Batavia
Conceptual designs of superconducting magnets (dipoles and quadrupoles) for a muon collider with a 1.5 TeV c.o.m. energy and an average luminosity of 1034 cm-2s-1 are presented. All magnets are based on the Nb3Sn superconductor and designed to provide an adequate operation field/field gradient in the aperture with the critical current margin required for reliable machine operation. In contrary to proton machines, the dipole magnets should have open midplanes, and, for some of them, the required good field quality region needs to have a vertical aspect ratio of 2:1 that imposes additional challenges for the magnet design. Magnet cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. The magnets and corresponding protective measures are designed to handle about 0.5 kW/m of dynamic heat loads from the muon beam decays. Magnet parameters are reported and compared with the requirements.
BNL, Upton, Long Island, New York
During the acceleration process, heavy ion beams in RHIC cross the transition energy. When RHIC was colliding deuterons and gold ions during Run-8, lattices with different integer tunes were used for the two rings. This resulted in the two rings crossing transition at different times, which proved beneficial for the "Yellow" ring, the RF system of which is slaved to the "Blue" ring. For the symmetric gold-gold run in FY2010, lattices with different transition energies but equal tunes were implemented. We report the optics design concept as well as operational experience with this configuration.
KACST, Riyadh
JINR, Dubna, Moscow Region
Cockcroft Institute, Warrington, Cheshire
At the National Centre for Mathematics and Physics (NCMP), at the King Abdulaziz City for Science and Technology (KACST), Saudi Arabia, a versatile low energy ion injector has been developed in collaboration with the QUASAR group. This project will allow for a broad experimental program with most different kinds of ions both in single pass setups, but also with ions stored in a fixed-energy electrostatic storage ring. In this contribution, the design of the injector is presented. It was designed for beams with energies of up to 30 kV/q and will allow for switching between different ion sources from e.g. duoplasmatron to electrospray ion sources and to thus provide the users with a wide range of different beams. The mechanical construction of the injector is summarized and the status of its assembly at KACST presented.
GSI, Darmstadt
The ESR storage ring at GSI is operated with a wide range of heavy ions. In addition to stable heavy ions also rare isotope beams are studied in various experiments. A novel method to provide one- or few-component cooled fragment beams has been demonstrated experimentally. This technique uses a primary high energy heavy ion beam (several hundred MeV/u) bombarding a thick target in front of the storage ring. The reaction products are first separated by the magnetic structure of the storage ring. After storage of isotopes in a rigidity window of typically ± 2 per mille the isotopes are cooled to the same velocity by electron cooling. The cooled ions are circulating on different orbits according to their mass and charge. The momentum spread of the individual components is on the order 0.01 per mille or smaller depending on the intensity. The different components are radially well separated in regions with large dispersion. By the use of mechanical scrapers beam components in a certain radial region, corresponding to a range in masses and charges, can be selected, This way the stored rare isotope beam is curtailed to the components of choice.
PTB, Berlin
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
For the operation of the Metrology Light Source (MLS)*, the electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB), as a primary radiation source standard all storage ring parameters have to be known absolutely. For the measurement of the electron beam size and the monitoring of the stability of the orbit location a new imaging system has been set up, that operates at very different intensity levels covering more than 11 decades, given by the variation of the electron beam current. The system uses a commercial zoom lens for the achromatic optical imaging of the electron beam source point onto two different camera systems. One camera system is for life-imaging of the electron beam at electron beam currents from 200 mA down to some μA. The second system is a cooled CCD-camera that allows imaging of the electron beam size and location at very low currents, down to only one stored electron.
* R. Klein et al., Phys. Rev. ST-AB 11, 110701 (2008).
MPI-K, Heidelberg
Kyoto ICR, Uji, Kyoto
A cryogenic storage ring (CSR) is under construction at MPI für Kernphysik, which will be a unique facility for low velocity phase space cooled ion beams. Among other experiments the cooling and storage of molecular ions in there rotational ground state is planed. To meet this requirement the ring must provide a vacuum with a residual gas density below 10000 molecules/cm3, which will be achieved by cooling the vacuum chamber of the ion beam to 2-10 K. The projected stored beam current will be in the range of 1 nA - 1 μA. The resulting low signal strengths on the beam position pickups, current monitors and Schottky monitor put strong demands on these diagnostics tools. The very low residual gas density of the CSR does not allow using a conventional residual gas monitor to measure the profile of the stored ion beam. Other methods were investigated to measure the profile of a stored ion beam. In the paper an overview of the CSR diagnostics tool and diagnostics procedures will be given.
JASRI/SPring-8, Hyogo-ken
The signal processing electronics of the SPring-8 Storage Ring BPM were replaced during the summer shutdown of 2006, and put into operation. However, a large filling pattern dependence was observed. The cause was attributed to the nonlinear response of the diodes to large pulse signals. The diode were attached in front of the RF switches for protection from the electrostatic discharge damages on the switch IC. We took a countermeasure for the filling pattern dependence by reducing the pulse height with a band pass filter (BPF) in front of each channel. The BPF were attached and put into the operation from November 2008. The effect of the BPF was evaluated using the beam with changing the filling patterns and repeating the position measurements. The differences of the measured position data across the filling pattern change were found to be within 10μmeters, which was the same amount of the orbit drift during the filling pattern change.
SESAME, Amman
SESAME machine consists of a 22.5 MeV microtron, 800 MeV booster and a 2.5 GeV storage ring. The electron beam diagnostics will play a major rule during the commisioning and normal operation with different modes of single bunch and multi bunch operations. Furthermore the beam parameteres during injection, acceleration and storing the beam will be measured, monitored and integrated into other subsystems. The major diagnostics components and the general design for booster and storage ring are reported in this paper.
USTC/NSRL, Hefei, Anhui
A new beam current monitor (BCM) has been implemented on Hefei Light Source (HLS) recently. It has been used for bunch-by-bunch beam current measurement, which is useful for filling control and longitudinal feedback, etc. The BCM consists of three parts: the front-end circuit, a high sampling rate oscilloscope for beam current signal acquisition and the data processing system. The signals from the beam position monitor of the storage ring are manipulated by the front-end circuit first, then sampled by the Agilent MSO7104 oscilloscope and transported into the control computer for data processing. The sampling rate of the oscilloscope is up to 4GHz and the trigger rate is 4.533 MHz. The data processing program is supported by the LabVIEW. The measurement of beam current in multi-bunch operation mode is described. Some important results are summarized.
SSRF, Shanghai
Bunch charge uniformity control is very important for storage ring top-up operation. In order to monitor filling pattern and measure bunch charge precisely an PXI waveform digitizer based data acquisition system was developed to retrieve bunch charge information from BPM pickup signals. Effective sampling rate could be extended to 400GHz by waveform rebuilding technology, which folds multi turns data into single turn with real time sampling rate of 8GHz. Online evaluation shows charge resolution could be better than 0.5% for 1nC range.
The University of Liverpool, Liverpool
MPI-K, Heidelberg
Cockcroft Institute, Warrington, Cheshire
Supersonic gas-jets have attracted much interest as experimental targets in several fields of science since they combine low internal temperatures with high directionality. Axisymmetric jets have found widespread application, triggering a wealth of studies on their properties, while only a limited number of detailed studies have been done on planar jets. In this paper, the design of a beam profile monitor based on a planar supersonic gas-jet for use in the Ultra-low energy Storage Ring (USR) at the Facility for Antiproton and Ion Research (FAIR) in Germany is described. Optimization of the monitor requires investigation into different characteristic jet parameters. For that purpose extensive simulation work with the Gas Dynamics Tool (GDT) was done. The results of these studies are presented together with a description of a novel nozzle-skimmer configuration and an experimental test stand to benchmark the numerical results.
USC, Los Angeles, California
SLAC, Menlo Park, California
SPEAR3 is a third-generation synchrotron light source storage ring. The beam stability requirements are ~10% of the beam size, which is about 1 micron in the vertical plane. Hydrostatic level system (HLS) measurements show that the height of the SPEAR3 tunnel floor varies by tens of microns daily. We present analysis of the HLS data, including accounting for common-mode tidal motion. We discuss the results of experiments done to determine the primary driving source of ground motion. We painted the accelerator tunnel walls white; we temporarily installed Mylar over the asphalt in the center of the accelerator; and we put Mylar over a section of the tunnel walls.
SINAP, Shanghai
Shanghai KEY Laboratory of Cryogenics & Superconducting RF Technology, Shanghai
The digital low level radio frequency (DLLRF) system and the beam trip diagnostic system in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been operational for more than one year. The DLLRF has successfully maintained the amplitude and phase stability of the cavity field in the superconducting cavity even when the beam current in the storage ring reached 300mA at 3.5GeV, and the beam trip diagnostic system has been realized and is helpful for improving the reliability of the RF system.
NSRRC, Hsinchu
The Taiwan Photon Source (TPS) is a third generation synchrotron accelerator which the designed energy will be 3 GeV whereas the current is 500mA. The role of crotch absorber is designed to protect downstream UHV vacuum chamber. It is is the only mask component to absorb large amount of synchrotron radiation (bending magnet) in the storage ring. Crotch absorber is installed from transverse direction of the bending chamber to intercept the power. Two bent OFHC copper tubes are vacuum brazed on the copper mask. A 30 degree groove is machined to face bending magnet fan. The reason is not only to dissipate the heat but also to limit back scattering to the rest of chambers. Top and bottom of the absorber are bolted with beryllium copper springs; they will provide extra support for the absorber after it is installed in the Aluminum chamber. Three thermocouples will be embedded inside of the mask to monitor the temperature gradient. Final prototype of the crotch absorber with thermal analysis, design and machined parts are also presented in this paper.
IHEP Beijing, Beijing
IHEP Beiing, Beijing
As a tau-charm factory like collider, the upgrade project of the Beijing Electron Positron Collider (BEPCII), has reached its first design value of luminosity. During the commissioning of its luminosity, beam optics recovery, machine parameters measurement, detector solenoid compensation, and instability cure are main problems we met. Besides commissioning the machine, beams were delivered to the users from high energy physics and synchrotron radiation. This paper summarizes the accelerator physics issues in the BEPCII luminosity commissioning.
Supported by National Natural Sciences Foundation of China (10725525)
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
Danfysik A/S, Jyllinge
The pre-accelerator microtron supplies an electron beam at 105 MeV for the Metrology Light Source (MLS) of the Physikalisch-Technische Bundesanstalt (PTB) in Berlin. The beam is delivered via the transfer line to the injection septum and then into the storage ring. This septum magnet has its stainless steel vacuum beam pipe placed inside a laminated silicon iron magnet core. Hence, the pulsed magnetic field (half sine) used for the beam deflection must propagate through the thin metallic beam pipe. During the commissioning of the injection process, it became apparent that the calculated nominal pulse current for this energy and geometry had to be increased by 30 % to achieve proper beam transfer and accumulation. Two problems were apparent. Firstly, the injected beam trajectory had to be set at an angle away from the main beam axis. Secondly, the beam transfer from the septum entrance to exit was disturbed. As a first measure, the septum current pulse length was extended from 35 to 107 μs. Further on, the septum magnet was insulated from the transfer line beam pipe by a ceramic brake. This paper reports on measurements of pulsed magnetic fields inside the septum magnet.
* Commissioning and Operation of the Metrology Light Source, J. Feikes et al., BESSY, Berlin, Germany; R. Klein, G. Ulm, Physikalisch-Technische Bundesanstalt, Berlin, Germany; EPAC08, Genoa, Italy.
SINAP, Shanghai
The injection system composed of four kickers and two septa in the SSRF have been built and operated. The commissioning shows that fine injecting efficiency and smaller disturbance are carried out. The septum magnets are eddy current designs with a sheet of magnetic screening material around the stored electron beam to reduce the leakage field. The beam tube with RF finger flanges at each end is added to keep the continuity of impedance for the circulating beam. The pulser excite the septum with 60μsecond waveform of half sine-wave and 8kA peak current. Four identical kicker magnets provide the symmetric bump in 10 meter long straight sections. The excitation waveform is a 3.8μsecond half sine pulse up to 7 kA peak. The emphasis was on achieving the best possible tracking in time of the magnet field waveforms so that the residual closed orbit disturbance is minimized for top-up injection. The performance of the injection system with these pulsed magnets are described.
I-Tech, Solkan
ESRF, Grenoble
Initially, the Libera Brilliance Single Pass was intended for beam position monitoring at injector system for the FEL machines, this was afterwards followed by the idea of using it on transfer lines on the 3rd generation light sources. The device can be used on pickup buttons and on striplines. The measurement principles and results of Libera Brilliance Single Pass at ESRF, as beam-charge monitor and injection-efficiency monitor, are presented.
NSRRC, Hsinchu
Pulsed magnet system of Taiwan Photon source(TPS) requires a very low stray field to avoid parasitic magnetic field into the stored beam. The stray field from storage ring(SR) injection septum is required to be less than 0.2 Gauss. The most common method to protect parasitic magnetic field is to use high permeability and conductivity material, such as a Mu-metal. A 1.2 ms half-sine wave pulse of up to 8280A current peak are supply to a septum and would result in eddy current loss in magnet and conductor current diffusion during the rapid charging on magnet. Moreover, competition between eddy current loss and magnetic permeability would lead to a complex phenomena inside the mumetal shielding cabinet and shielding performance. In this study, the magnetic shielding performance of a shielding cabinet was examined in different shielding cabinet geometry and thickness. The results were calculated in Opera software and show that there is a significant suppression of SR septum stray field when round shielding cabinet is in use.
BNL, Upton, Long Island, New York
Injection into a ring requires that the injected beam be optimally matched to the storage ring lattice. For on axis injection this requires that the twiss functions of the transfer line match the twiss functions of the lattice. When injection off axis, as is done in light sources for top off injection, the goal is to use the minimum phase space area in the storage ring. A. Streun* has given an analytical method to compute the twiss functions for top off injection into the SLS where injection occurs at a beam waist. We have extended his theory to include cases where there is no beam waist. A simple analytical formula is not possible in this case, however we give an algorithm to compute the twiss parameters of the injected beam given the storage ring lattice. We also compute the twiss functions for a variety of cases for the NSLS-II storage ring.
* A. Streun. "SLS booster-to-ring transfer line optics for optimum injection effciency". Technical Note SLS-TME-TA-2002-0193. May 27, 2005.
BNL, Upton, Long Island, New York
The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster synchrotron and associated transport lines. The transport lines need to transport the beam from the linac to the booster and from the booster to the storage ring in a way that provide high injection efficiency. In this paper we discuss progress on specifying and prototyping the NSLS-II transfer lines including diagnostics, magnet specifications, and safety systems. Commissioning plans are also discussed.
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
The electron cloud, which is initially presumed as a homogeneous distribution of static electrons, changes its transverse centroid position very fast during the passage of even a single bunch. This is due to the strong focusing transverse field of the highly relativistic positron bunch. As the density of the electrons near the beam axis grows, its impact on the beam becomes stronger. The interaction of the electron cloud with the bunch results with the shift of the betatron tune of the coherent dipole motion of the beam. In this paper we simulated the dipole tune shift of the beam interacting with the electron cloud by taking also in to account the own space-charge forces of the electrons which strongly affect the motion of the electrons during the passage of the bunch. We computed the tune shift for different transverse size and density of the electron cloud.
IMP, Lanzhou
Two electron cooling devices have been used at HIRFL-CSR in order to provide high quality heavy ion beams for nuclear and atomic research. The momentum spread is one of the most important characteristics of the beam quality. At HIRFL-CSR, the momentum spread is measured directly with the aid of longitudinal Schottky spectra system. In this paper, the measurements for various ion species are presented. At relatively high intensity, longitudinal Schottky spectra is double peak due to collective phenomena and the momentum spread can be obtained by fitting the spectra. The dependence of momentum spread on stored particle number is proportional to N**a. Moreover, the heating factor was investigated after switching off the electron cooling. The residual gas scattering, the intrabeam scattering and instabilities are studied according to the measured data.
MPI-K, Heidelberg
GSI, Darmstadt
JINR, Dubna, Moscow Region
Cockcroft Institute, Warrington, Cheshire
Electrostatic storage rings have proven to be invaluable tools for atomic and molecular physics. Due to the mass independence of the electrostatic rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged bio-molecules. However, earlier measurements showed strong space charge limitations; probably linked to non-linear fields that cannot be completely avoided in such machines. The nature of these effects is not fully understood. In this contribution, we present the results from simulating an electrostatic storage ring under consideration of non-linear fields as well as space charge effects using the computer code SCALA.
ASCo, Clayton, Victoria
Melbourne
The Australian Synchrotron storage ring must maintain a stable electron beam for user operations. The impedance characteristics of the storage ring can give rise to instabilities that adversely affect the beam quality and need to be well understood. Collective effects driven by the resistive wall impedance are particularly relevant at the Australian synchrotron and their strengths are enhanced by small gap insertion devices, such as IVUs. This study will explore the impedance issues identified in the Australian Synchrotron storage ring and current mitigation techniques.
Karlsruhe Institute of Technology (KIT), Karlsruhe
KIT, Karlsruhe
FZK, Karlsruhe
LNLS, Campinas
We present results of a series of measurements aimed at characterizing the beam coupling impedances in the ANKA electron storage ring. The measurements include transverse coherent tune shifts, bunch lengthening and synchronous phase shift as a function of single bunch current. These were performed under a variety of conditions in the ANKA ring, including injection energy (500 MeV), nominal operating energy (2.5 GeV) as well as at 1.3 GeV and in the low alpha mode and are part of a longer term effort to understand the ANKA impedance over a wide frequency range.
MPI-P, München
SINAP, Shanghai
SSRF, Shanghai
Fast ion instability has been observed in the early commissioning and operation of the Shanghai Synchrotron Radiation Facility (SSRF) storage ring. In this paper, a weak-strong code is used to simulate the fast ion instability in SSRF storage ring. Various fill patterns and gas pressures are investigated. The results show that the mini-train fill patterns are very effective to suppress the growth of the fast ion instability. By employing a fast feedback system, it is possible to damp the growth of beam oscillation amplitude below the beam size.
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is a new third generation synchrotron storage ring which will be built at the present site of the NSRRC. The paper summarizes results of the impedance studies of the storage ring vacuum components for the TPS project. The main goal of this work was to support the design of the vacuum chamber and, at the same time, to get a detailed model of the machine impedance, which can be used later for detail studies of collective effects. Wake potentials and impedances for each component of the storage ring have been simulated with a 3D electromagnetic code GdfidL. Numerically obtained data have been compared to analytical results for simplified geometries of the vacuum chamber components.
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is a new third generation synchrotron storage ring which will be built at the present site of the NSRRC. Collective effects in the TPS storage ring have been simulated with tracking code ELEGANT. Quasi-Green's function for the entire ring and coherent synchrotron radiation (CSR) have been taken into account in the simulations. Thresholds of the longitudinal microwave instability and the CSR induced instability have been estimated. Time-dependent sawtooth oscillations of the bunch length at high bunch currents have been analyzed and compared to the bunch length oscillations observed at the SLC damping ring.
Diamond, Oxfordshire
JAI, Oxford
SOLEIL, Gif-sur-Yvette
Within the common programme on the analysis of collective instabilities at Diamond and SOLEIL, the numerical codes mbtrack and sbtrack have been extended to include a full description of the nonlinearities in the storage rings by means of the nonlinear one-turn map. We present the details of the map implementation and the recent results on the analysis of the effects of the nonlinear terms of the map on the characteristics of the collective instabilities at the two machines.
IUCF, Bloomington, Indiana
ORNL, Oak Ridge, Tennessee
The instability caused by the electron cloud effect (ECE) may set an upper limit to beam intensity in proton storage rings. This instability is potentially a major obstacle to the full intensity operation, at 1.5·1014 protons per pulse, of the Spallation Neutron Source (SNS). High intensity experiments have been done with different sets of parameters that affect the electron-proton (e-p) instability, of which bunch intensity and bunch shape are considered as two main factors. In the experiment, the phase and amplitude of the second harmonic RF cavity are used to modify the bunch shape. Simulation with the beam dynamics code ORBIT has been carried out to compare with experimental results and to understand the impact of bunch shape on electron cloud build-up and beam stability. We have also attempted to benchmark the e-p model to predict the frequency spectrum and the RF buncher voltage threshold values against experimental results. Details and discussion will be reported in this conference.
* M.T.F. Pivi and M.A. Furman, PRSTAB 6, 034201 (2003)
** V. Danilov et. al, 39th ICFA Advanced Beam Dynamics Workshop, 2006
*** B. Macek et. al, PAC 2003
Nagoya University, Nagoya
UVSOR, Okazaki
Sokendai - Okazaki, Okazaki, Aichi
We are developing an ultra-short gamma ray pulse source based on laser Compton scattering technology at the 750 MeV electron storage ring UVSOR-II. Ultra-short gamma ray pulses can be generated by injecting femtosecond laser pulses into the electron beam circulating in an electron storage ring from the direction perpendicular to the orbital plane. The energy, intensity, and pulse width of the gamma rays have been estimated to be 6.6 MeV, 2.4× 106 photons s-1, and 150 fs, respectively, for the case of UVSOR-II with a commercially available femtosecond laser. These parameters can be tuned by changing the incident angle of the laser to the electron beam, electron energy, and the size of the laser. A preliminary head-on collision experiment was carried out. The measured spectral shape agreed well with simulation including the detector response calculated by the EGS5 code*, which implied the generation of gamma rays by laser Compton scattering and the validity of the estimation of the gamma ray intensity in the case of 90-degree collisions.
* H. Hirayama et al., SLAC-R-730, (2005).
AIST, Tsukuba, Ibaraki
Recently, an FEL in the near-infrared (IR) region was oscillated at a compact storage ring NIJI-IV whose circumference was 29.6 m. We have been developed a device for the storage ring FEL in the IR region with a 3.6-m optical klystron ETLOK-III, and the first lasing at a wavelength of around 1450 nm was achieved at February 2009. The maximum power of the FEL was 0.3 mW per vacuum window and the relative linewidth was 3·10-4.* Moreover, gamma-ray beam was also produced in the long straight section of NIJI-IV by Compton backscattering of the intra-cavity IR FEL and the stored electron beam with an energy of 310MeV. After the first lasing experiment, we have successfully performed to extend the lasing wavelength region and increase FEL power, and this recent progress will be presented.
* N. Sei, H. Ogawa, K.Yamada, Opt. Lett. 34 (2009) 1843.
IUCF, Bloomington, Indiana
At the Indiana University Cyclotron Facility (IUCF), we are developing a new XFEL concept, which is based on the Compton scattering and the laser undulator instead of the conventional magnetic undulator. Since the period of the laser undulator is only about 500 nm, the coherent hard X-rays can be generated by using a compact electron accelerator with a beam energy of about 50 MeV. In this paper, we report an estimation of the energy spread growths due to the Compton scattering itself and their impacts on the XFEL lasing in the laser undulator based XFEL concept.
SOLEIL, Gif-sur-Yvette
ANL, Argonne
SOLEIL is presently installing a laser bunch slicing set-up to produce ultra-short X-ray pulses. We propose a method to generate coherent synchrotron radiation at high harmonics in a storage ring using an echo scheme. Like in the method proposed recently for free electron lasers, the echo scheme uses two modulators and two dispersive sections. We show that this can be done at the synchrotron SOLEIL by adapting the classical slicing scheme. In the present study at SOLEIL, the two laser/electrons interactions are planned to occur in two out of vacuum wigglers of period 150 mm, and the high harmonic radiation will be emitted in an APPLE-II type undulator with a period of 44mm or 80 mm in the beamline TEMPO or with a period of 52 mm in the beamline DEIMOS.
Stanford University, Stanford, California
SLAC, Menlo Park, California
By operating SPEAR3 in the quasi-isochronous (low-alpha) mode, one can produce synchrotron radiation with pulse durations of order 1ps. Applications include pump-probe x-ray science and the production of THz radiation. Measurements of short pulse lengths are difficult, however, because the light intensity is low and streak camera resolution is of order 2ps. Bunch arrival time and timing jitter are also important factors. In order to further quantify the pulse length and timing system performance, a 5MHz, 50fs mode-locked laser was used to cross-correlate with the visible SR beam in a BBO crystal. The 800nm laser pulse was delayed with a precision mechanical stage and the product SHG radiation detected with a photodiode / lock-in amplifier using the ring frequency as reference. In this paper we report on the experimental setup, preliminary pulse length measurements and prospects for further improvement.
SINAP, Shanghai
The Shanghai Synchrotron Radiation Facility (SSRF), a 3.5GeV storage ring based third generation light source, started its user operation with 7 beamlines in May 2009. During the passed year, the facility reliably operated about 4000 hours for user experiments. This paper presents the operational status of the SSRF in the first year and its future performance improvement plans.
ASCo, Clayton, Victoria
The Australian Synchrotron has been running normal operations for beamlines since April 2007. The high degree of beam availability has allowed for an extensive accelerator physics program to be developed. The main points of this program will be presented, including student involvement at different levels and developments being made in anticipation of moving to top-up mode injections.
LNLS, Campinas
Karlsruhe Institute of Technology (KIT), Karlsruhe
In the beginning of 2008 an upgrade of the beam position monitors (BPMs) of the Brazilian Synchrotron Light Source (LNLS) electron storage ring was decided and scheduled as part of the continuous effort to improve the electron beam orbit stability. The objective was to replace most of the 24 BPMs installed in the storage ring and install new radiation absorbers inside the vacuum chamber. The original stripline BPMs were sensitive to temperature changes in the vacuum chamber. Heat, which induced mechanical stress in the striplines, could lead to fluctuations in the position readings thereby disturbing the orbit stability. The problem affected differently the BPMs. Although not a great issue during a typical user shift, the perturbations could pose some problems for the most sensitive experiments. One third of the BPMs were replaced in October 2008 and the remaining in October 2009. Thus, this large vacuum intervention aimed at improving the thermal and mechanical stability of the electron beam orbit measurement system. Finally, it will be presented the main changes made in the vacuum chambers and a survey of the evolution of the vacuum system after both interventions.
LNLS, Campinas
The main facility of the Brazilian Synchrotron Light Laboratory is a 93 meters circumference, 1.37 GeV storage ring. Recently, the first superconducting insertion device was installed in the machine. This 4 T ID produces powerful beams that can damage the non-cooled parts of the accelerator vessel in the case of a miss-steered beam, even with a relatively large vacuum chamber cross section. In this paper we present the design details and the first operational results of the electronic beam position interlock system. Topics about redundancy engineering will be discussed as well.
CLS, Saskatoon, Saskatchewan
Preliminary observations of coherent synchrotron radiation (CSR) at the Canadian Light Source have been reported earlier. At that time a more suitable operating point was identified based on particle tracking calculations. These calculations showed that a large stable longitudinal phase space can be achieved through adjustment of the chromaticities. With the implementation of these operating conditions CSR has been produced with much improved beam lifetime. CSR has been produced both with multiple bunches at 1.5 GeV and with a single bunch at the nominal 2.9 GeV beam energy. The production of CSR with these new operating points has proven to be reliable and repeatable. Operations at the nominal beam energy allows for setup times of under 20 minutes. With a beam lifetime (1/e) of over 7 hours single shifts dedicated to CSR production are now practical.
ISA, Aarhus
At Aarhus University in Denmark, a new synchrotron radiation source is being built. The 46-m circumference storage ring with 6-fold symmetry will operate at 580 MeV to produce bright UV and soft x-ray radiation. The storage ring will have a horizontal emittance of around 10 nm. Four straight sections will be available for insertion devices including a 12-pole wiggler with a field of 2 Tesla. ASTRID2 will operate in top-up mode with electrons from the present storage ring ASTRID, used as a booster. The insertion devices will have a strong influence on the lattice, and studies of dynamical aperture and compensation of tunes and beta beat will be presented. Also injection simulations will be given. The technical layout with details about magnetic arrangements on girders will be shown, including the vacuum system with extensive use of NEG. A 105 MHz RF system is being built together with a new LLRF system. At present, most major components have been ordered, and first injection will take place in the first half of 2011.
SOLEIL, Gif-sur-Yvette
UPMC, Paris
LIXAM, Orsay
An electron bunch slicing set-up is being installed on the SOLEIL storage ring, based on Zholents and Zolotorev method [1]. This will provide 100 fs long X-ray pulses with reasonable flux to two existing beamlines, working with soft X-rays (TEMPO) and hard X-rays (CRISTAL). The parameters of the laser system and of the wiggler modulator, and the optimisation of the laser focusing optics and beam path, from the laser hutch in the experimental hall to the inside of the storage ring tunnel have been finalised. The construction work will start early 2010, including the ordering of the laser, the construction of the laser hutch, the construction of the wiggler, the installation of a new modified vacuum dipole chamber by which the laser will enter into the ring, and the modifications of some components in the beamlines front-ends to provide the best possible separation of the sliced X-Ray. In this paper, we will report on the status of the installation of the set-up and the expected performances including laser-electron interaction efficiency, halo background effect and the possible operation filling patterns.
ESRF, Grenoble
After 15 years of highly successful user operation, the Council of the ESRF are funding an ambitious 7 year upgrade programme (2009-2015) of the European Synchrotron Radiation Facility. In this context the accelerator complex will benefit from a number of upgrades. Several insertion device straight sections will be lengthened from five to six meters. The beamline scientific capacities will be increased by operating some straight sections in the canting geometry. New insertion devices will be built to fulfill the requirements of the scientific programme. The RF system also faces a major reconstruction with the replacement of some klystron based transmitters by high power solid state amplifiers and the development of HOM damped cavities operating at room temperature. The orbit stabilisation system system will be renovated. This paper reports on the present operation performances of the source, highlighting the recent development, as well as the advancement of the upgrade projects.
KIT, Karlsruhe
A dedicated optics with a low momentum compaction factor is used at the ANKA storage ring to reduce the bunch length to generate coherent synchrotron radiation (CSR). A double sweep streak camera is employed to determine the bunch length and shape for different optics and as a function of the beam current. Measurements of the longitudinal bunch profile have been performed for many different momentum compaction factors and various bunch currents. This paper describes the set up of the streak camera experiments and compares the measured bunch lengths to theoretical expectations.
KIT, Karlsruhe
Technische Universität Berlin, Berlin
DLR, Berlin
In synchrotron radiation sources coherent radiation is emitted when the bunch length is comparable to or shorter than the wavelength of the emitted radiation. At the ANKA storage ring this radiation is observed as so-called edge radiation (emitted in the fringe field of a bending magnet). This radiation exhibits a radial polarisation pattern. The observed pattern, however, is influenced by the radiation transport in the beam line. A detector system based on a superconducting NbN ultra-fast bolometer with an intrinsic response time of about 100 ps as well as conventional Si bolometers were used to study the beam polarisaion. This paper reports the observations made during measurements.
IPM, Tehran
An overview of the 3 GeV Synchrotron radiation source, which is under design in Iran will be presented with emphasis on site location studies, user demands and general parameters of the machine. The background to the proposed facility and different aspects of the machine design also is reported. Operating this third generation light source with 3 GeV storage ring and beam currents of up to 400mA, will result in a source of very intense light over a broad range of photon energies from the IR to hard X-rays to a community that is expected to exceed 500 users a few years after the start of operation in 2015 .
ELETTRA, Basovizza
Elettra established top-up operations taking advantage of its new full energy injector. The safety simulations and personnel safety conditions, the radiation measurements, the implementation and the operations of the whole system are presented and discussed.
HSRC, Higashi-Hiroshima
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
SHI, Tokyo
The HiSOR is a synchrotron radiation (SR) source of Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, established in 1996. HiSOR is a compact racetrack-type storage ring having 21.95 m circumference, and 400-nmrad natural emittance, which is not so small compared with those of other medium~large storage rings. There are 14 beamlines on HiSOR, but the ring has only two straight sections for undulators which are obviously not compatible with modern SR facilities. Therefore, we are planning to construct a compact storage ring, 'HiSOR-II' in which undulators are dominant light sources. We refer to the electron storage ring MAX-III as the best models to design HiSOR-II lattice. This 700 MeV storage ring is designed that the circumference is equal to or less than 50 m so that it can fit in our existing site. It has several straight sections for undulators, and its natural emittance is about 14nmrad. The booster ring aiming for the top-up injection is constructed on the inside basement of HiSOR-II. This layout brings advantages in radiation shielding and prevention of magnetic field interference between two rings.
NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
JASRI/SPring-8, Hyogo-ken
The periodic fluctuations and drifts in the radiation intensity have been observed at the NewSUBARU synchrotron radiation facility. To clarify the cause of this problem we have measured temperatures of air, cooling water, equipments and building with the network-distributed data logger. And we found that temperature fluctuations in both air in the shielded tunnel and the cooling water mainly affect the stabilities of electron beam orbit and optical axis. To maintain a constant temperature, the large doors for carrying equipment at the experimental hall were covered with insulated curtains, and we optimized PID parameters of temperature controllers for air and water. As results, the periodic fluctuations almost disappeared, but some drifts were still remained, which are due to slow variations of equipment temperature. By realizing the automatic COD correction, the drift in electron beam position could be suppressed and the fluctuations of radiation intensity observed at beam-lines became smaller than they used to be. For further stabilization, we recently introduced a XBPM upstream in a beamline to measure the vertical position of radiation axis precisely.
JASRI/SPring-8, Hyogo-ken
The SPring-8 storage ring has been operated for more than ten years and provided brilliant hard X-ray radiation to users. In recent years there are some discussions on upgrade plans of existing synchrotron radiation facilities and proposals of new facilities. In these the target brilliance of photons is set to be comparable or even higher, in some energy range, than that of the present value of SPring-8. At SPring-8 a design study of a new storage ring is now in progress for the future upgrade plan. The lattice structure will be changed from the present double-bend type to the multi-bend one, keeping the source position of all insertion devices unchanged. The emittance will be lowered from the present value of 3.4nmrad at 8GeV to 0.4nmrad at 6GeV (or 0.8nmrad at 8GeV) in the case of triple-bend lattice and 0.2nmrad at 6GeV (or 0.3nmrad at 8GeV) in the case of quadruple-bend lattice. We will report the present state of our preliminary work on lattice design. Nonlinear resonance correction to enlarge the dynamic aperture for on- and off-momentum electrons will also be discussed.
JASRI/SPring-8, Hyogo-ken
We indicated that a storage ring with picometer-order emittance is possible with realistic parameters and is promising as a next generation synchrotron radiation source* and applied it to the SPring-8 storage ring**. The storage ring had the same circumference as that of the SPring-8 storage ring, but had not four long straight sections that SPring-8 storage ring has. Accordingly, the storage ring beam line is slightly different from that of the SPring-8 and the positions of photon beam lines are also different from the existing one. To avoid this, a storage ring with four long straight sections has been studied and was found that the storage ring with the same beam line positions as the existing one is possible. The storage ring consists of twenty ten-bend achromat cells, four five-bend achromat cells and four long straight sections. The long straight section length is 34.0 m and the short one is 6.6 m. The natural emittance is 108 pm-rad. The maximum brightness is 2.5×1022 photons/s/mm**2/mrad**2 in 0.1% BW with 200 mA beam current, about 160 times brighter than SPring-8. In the end I mention that this ultra-low emittance storage ring is only a result of personal design study.
* K. Tsumaki and N. Kumagai, Nucl. Instr. and Meth. A 565 (2006) 394.
** K. Tsumaki and N. Kumagai, EPAC'06, 3362.
KEK, Ibaraki
A hybrid fill mode has been tested at the Photon Factory storage ring (PF-ring). The hybrid fill mode consists of a train of low-current bunches and a high-current single bunch. Since a bunch-by-bunch feedback system was not available because of the high contrast of currents between the bunch train and the single bunch, we suppressed multibunch instabilities in the transverse and longitudinal planes by using the octupole magnets and RF phase modulation, respectively. We also suppressed single-bunch instabilities by controlling ring chromaticity. As a result, we successfully stored a 450 mA current with the hybrid fill mode: 1/2 filling (2.56 mA/bunch × 156) + 1 single bunch opposite to the bunch train (50 mA/bunch). The distribution of vacuum pressures along the ring was similar for the hybrid fill and the typical single-bunch mode. In this conference, we will present the results of this test experiment as well as some future subjects to be solved for the user operation.
Nagoya University, Nagoya
KEK, Ibaraki
UVSOR, Okazaki
SAGA, Tosu
JASRI/SPring-8, Hyogo-ken
Central Japan Synchrotron Radiation (SR) Research Facility is under construction in the Aichi area, and the service will start from FY2012. Aichi Science & Technology Foundation is responsible for the operation and management, and Nagoya University SR Research Center is responsible to run the facility and support the users technically and scientifically. The accelerators consists of an injector linac, a booster synchrotron and an 1.2 GeV electron storage ring with the circumference of 72 m. To save construction expenses, the 50 MeV linac and the booster with the circumference of 48 m are built at inside of the storage ring. The beam current and natural emittance of the storage ring are 300 mA and 53 nmrad. The magnetic lattice consists of four triple bend cells and four straight sections 4 m long. The bending magnets at the centers of the cells are 5 T superbends and the critical energy of the SR is 4.8 keV. More than ten hard X-ray beam-line can be constructed. One variable polarization undulator will be installed in the first phase. The electron beam will be injected from the booster with the full energy and the top-up operation will be introduced as early as possible.
Nagoya University, Nagoya
UVSOR, Okazaki
KEK, Ibaraki
KURRI, Osaka
Sokendai - Okazaki, Okazaki, Aichi
Terahertz (THz) coherent synchrotron radiation (CSR) is emitted not only from shorter electron bunches compared with the radiation wavelength but also from electron bunches withμstructures. Formation ofμstructures at sub picosecond scale in electron bunches by a laser slicing technique is experimentally studied through observation of THz CSR. The properties of the THz CSR such as intensity or spectrum depend strongly on the shape and amplitude of theμstructure created in the electron bunches. To study in detail the formation ofμstructure in electron bunches using the laser slicing technique, we have performed experiments at the UVSOR-II electron storage ring. THz CSR, which contains information on theμstructure, was observed under various laser conditions. The THz CSR spectrum was found to depend strongly on the intensity and the pulse width of the laser. The results agreed qualitatively with a numerical calculation. It was suggested that the evolution of theμstructure during CSR emission is important under some experimental conditions.
UVSOR, Okazaki
Nagoya University, Nagoya
KURRI, Osaka
Sokendai - Okazaki, Okazaki, Aichi
UVSOR, a 750 MeV synchrotron light source of 53m circumference had been operated for more than 20 years. After a major upgrade in 2003, this machine was renamed to UVSOR-II. The ring is now routinely operated with low emittance of 27 nm-rad and with four undulators. By utilizing a part of the existing FEL system and an ultra-short laser system, coherent synchrotron radiation in THz range and coherent harmonic generation in VUV range have been extensively studied under international collaborations. Based on results obtained from previous coherent light source developments, a new five-year research program on the coherent light source developments has been started from FY2008, which includes creation of a new 4-m long straight section by moving the injection point, upgrades of the undulator and the laser system and construction of dedicated beam-lines for these coherent light sources. Present status and upgrade plan on these coherent light sources at UVSOR-II will be presented at the conference.
UVSOR, Okazaki
Sokendai - Okazaki, Okazaki, Aichi
Nagoya University, Nagoya
UVSOR-II is a low emittance, 750 MeV synchrotron light source. Low emittance and low energy synchrotron light sources naturally suffered from short electron lifetime due to Touschek effect. Top-up operation is a solution for overcoming the effect. In the UVSOR-II, trials of multi-bunch top-up operation at the full energy were started from 2008. In the trials, we have succeeded in keeping the stored beam current around 300 mA for 12 hours. From this fiscal year, single bunch injection was started for single bunch user operations and for experiments on advanced light source development such as Free Electron Laser (FEL), Coherent Synchrotron Radiation (CSR), Coherent Harmonic Generation (CHG), which require single bunch or 2-bunch filling operation. We have already performed single bunch top-up operation in user time with the stored beam current of 50 mA. And FEL lasing with top-up operation was also achieved at the laser wavelength of 215 nm with the stored beam current of 130 mA / 2-bunch. In the FEL lasing experiment, we succeeded in keeping the average power of FEL around 130 mW for three hours.
SAGA, Tosu
Saga Light Source (SAGA-LS) is a synchrotron radiation facility with a 255 MeV linac and a 1.4 GeV storage ring. The spectral range covers from VUV to hard X ray region of about 23 keV. Improvement and development of the accelerator have been achieved from official opening of the facility. Stored current of the storage ring has been increased from 100 mA to 300 mA in these three years. An APPLE-2 undulator was developed and installed to a long straight section LS3. A field correction system for the undulator was developed to compensate precisely betatron tune shift, dipole kick and skew quadrupole. A superconducting wiggler is under construction. The peak field and critical energy are 4 T and 5.2 keV, respectively. The wiggler will provide synchrotron radiation in the 20-40 keV range. The wiggler consists of a superconducting main pole and two normal conducting side poles. The main pole is directly cooled by a small GM cryocooler and liquid helium is not used. In addition, laser Compton scattering experiment is under progress. A port to introduce CO2 laser light was installed as a beam line BL1. First gamma ray was observed in December 2009.
USTC/NSRL, Hefei, Anhui
HLS (Hefei Light Source) is a dedicated synchrotron radiation research facility, whose emittance is relatively large. In order to improve performance of the machine, especially getting higher brilliance synchrotron radiation and increasing the number of straight sections for insertion devices, an upgrade project is on going. A new low emittance lattice, which keeps the circumference of the ring no changing, has been studied and presented in this paper. For the upgrade project, a new ring will be installed on current ground settlement of HLS and all of the magnets will be reconstructed. After optimization, two operation modes have been chosen for different users. Nonlinear dynamics shows that dynamic aperture for on-momentum and off-momentum particle is large enough. Beam lifetime has also been studied. Calculation results proves that expected beam lifetime about 8.5 hours can be obtained with a fourth harmonic cavity operation.
USTC/NSRL, Hefei, Anhui
The Hefei Light Source is composed of an 800 MeV storage ring, a 200 MeV electron linac and transfer line, which was designed and constructed twenty years ago. Several factors limit the performance of HLS, for example, less number of insertion devices and large beam emittance. To meet the requirements of synchrotron radiation users, an upgrade project of HLS will be carried out in the next two years. Several sub-systems will be renewed, such as magnet system, power supply, beam diagnostics, vacuum system, etc. The upgrade scheme is described in this paper, including magnet lattice design, nonlinear performance, collective effects,beam injection, orbit detection and correction, injector, etc.
SINAP, Shanghai
The SSRF (Shanghai Synchrotron Radiation Facility) storage ring consisting of 20 Double Bend Achromatic cells with four super-periods is designed with a low emittance of 3.9nm.rad on 3.5GeV beam energy. Commissioning of the storage ring began on Dec. 21st 2007, and the beam was stored within sixty hours. After one and a half years commissioning, all specifications of the storage ring were reached in 2009. In this paper, study of beam dynamics in the SSRF storage ring is presented. Results of the measurement are given in detail, such as model calibration, orbit stability, etc.
SINAP, Shanghai
Beam optics design is a crucial issue in modern synchrotron radiation facility. A design approach of the beam optics is presented here. It provides much convenience for effectively exploring achievable linear optics and globally investigating flexibility of a complex lattice with super-periodicity. Low-ε optics and low-αC optics are emphasized, and the SSRF storage ring is taken as a test lattice.
PAL, Pohang, Kyungbuk
POSTECH, Pohang, Kyungbuk
The PAL (Pohang Accelerator Laboratory) has been carrying out the performance upgrade project, PLS-II. The lattice of the storage ring for PLS-II was changed in whole. The energy was increase from 2.5GeV to 3.0GeV thus many magnets installed in storage ring at present should be replaced with new one or modified. The field of the quadrupole and sextupole magnets will be measured using the rotating coils that are newly fabricated with the engineering ceramic for the first time at PAL. The data acquisition system for the field measurement was also rebuilt to make it simple and to have a good signal to noise ratio. In this presentation, the design parameters of the ceramic rotating coil are described. And various characteristics of the field measurement system are also presented
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The Synchrotron Light source ALBA is entering the commissioning period and beam should be provided to the users by the end of 2010. The installation of the full energy 3 GeV booster is finished, with the commissioning taking place in January 2010. The installation of the storage ring is almost finished and the commissioning should take place in summer 2010. The detailed milestones of the project are presented.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The Booster of the ALBA synchrotron light source will inject, in top up mode, up to 2 mA of current at 3Hz into the storage ring. The booster ramps the energy from 100 MeV (Linac) up to the 3 GeV of the storage ring. The RF system of the booster consist of a 80 kW IOT amplifier, a WR1800 waveguide system, a 5-cell Petra cavity and a Digital LLRF system. In this paper we will present a short description of the system, its performance during the commissioning phase and the results of operation with beam.
MAX-lab, Lund
In 2009 the MAX IV facility was granted funding by Swedish authorities. Construction of the facility will begin this summer and user operation is expected by 2015. MAX IV will consist of a 3.4 GeV linac as a driver for a short-pulse radiation facility (with planned upgrade to a seeded/cascaded FEL) as well as an injector for two storage rings at different energies serving user communities in separate spectral ranges. Thanks to a novel compact multibend-achromat design, the 3 GeV ring will deliver a 500 mA electron beam with a horizontal emittance below 0.3 nm rad to x-ray insertion devices located in 19 dispersion-free 5 m straight sections. When the 3 GeV ring goes into operation in 2015 it is expected to become the highest electron-brightness storage ring light source worldwide. The 1.5 GeV ring will serve as a replacement for both present-day MAX II and MAX III storage rings. Its below 6 nm rad horizontal emittance electron beam will be delivered to infrared and UV insertion devices in twelve 3.5 m straight sections. We report on design progress for the two new storage rings of the MAX IV facility.
Ankara University, Faculty of Sciences, Tandogan/Ankara
The Turkish Accelerator Center (TAC) is a project for accelerator based fundamental and applied researches supported by Turkish State Planning Organization (TSPO). The proposed synchrotron radiation facility of TAC was consisted of 3.56 GeV positron ring for a third generation light source. In the first study, it was shown that the insertion devices with the proposed parameter sets produce maximal spectral brightness to cover 10 eV - 100 keV photon energy range. Now, in this study it is considered that the electron beam energy will be increased to 4.5 GeV, in order to obtain more brightness light and wide energy spectrum range, also the beam emittance reduced to 1 nm.rad.
Diamond, Oxfordshire
Diamond Light Source has delivered beam for users exclusively in top-up mode since the end of October 2008. In this mode, a small number of single bunches are injected into specific buckets of the storage ring every ten minutes in order to maintain a constant beam current and fill pattern. During top-up the storage ring current is held within a window of approximately 1.5mA around the target current, generally 250mA, for a variety of fill patterns, including a two-thirds storage ring fill and a hybrid fill in which an intense single bunch is added to the normal fill pattern. Top-up has run continuously for several days on many occasions, with injection efficiency into the storage ring of typically 60%-95% even with 10 in-vacuum insertion device in operation with a permitted minimum gap of 5 mm. The effect of insertion devices, pulsed magnet stability and storage ring beam optics on top-up reliability and performance is examined, and the development of tools for the control of top-up and storage ring fill is detailed.
FEL/Duke University, Durham, North Carolina
The light source research program at the Duke Free-Electron Laser Laboratory (DFELL) is focused on the development of accelerator-driven light sources, including storage ring based free-electron lasers (FELs) and Compton gamma-ray source, the High Intensity Gamma-ray Source (HIGS). The HIGS is the most intense Compton gamma-ray source currently available with an energy tuning range from 1 to 100 MeV. The accelerator physics program at the DFELL covers a wide range of activities, from nonlinear dynamics research, to the study of beam instability with advanced feedback systems, to FEL research and development. In this paper, we will report our recent progress in accelerator physics research and light source development to meet new challenges of today's and future accelerators.
BNL, Upton, Long Island, New York
We discuss status and plans of development of the NSLS-II injector. The injector consists of 200 MeV linac, 3-GeV booster, transport lines and injection straight section. The system design is now nearly completed and the injector development is in the procurement phase. The injector commissioning is planned to take place in 2012.
KEK, Ibaraki
Most of the magnet power supplies of the KEKB rings and beam transport lines are connected to the local control computers through ARCNET. For this purpose we have developed the Power Supply Interface Controller Module (PSICM), which is designed to be plugged into the power supply. It has a 16-bit microprocessor, ARCNET interface, trigger pulse input interface, and parallel interface to the power supply. According to the upgrade plan of the KEKB accelerators, more power supplies are expected to be installed. Although the PSICMs have worked without serious problem for 11 years, it seems too hard to keep maintenance for the next decade because some of the parts have been discontinued. Thus we decided to develop the next generation of the PSICM. Its major change is the use of the Ethernet instead of the ARCNET. On the other hand the specifications of the interface to the power supply are not changed at all. The new PSICM is named ePSICM (Ethernet-based Power Supply Interface Controller Module). The design of the ePSICM and the development of the prototype modules are in progress.
SINAP, Shanghai
Soft IOC is an ideal solution for high level global application of accelerator control and beam diagnostics due to easy online modification and rebooting. SSRF beam diagnostics system employees two soft IOCs to handle global tasks such as BPMs group access, orbit performance analyze and online data reliability analyze, which are hardly performed in bottom level IOC side and OPI side. This paper introduces the current status and future upgrade plan.
NSRRC, Hsinchu
In order to help early development of TPS control system and user interface, a virtual accelerator model is constructed. The virtual accelerator has been created by AT toolbox and simulated beam behavior; the Middle Layer providing high level accelerator application is also used. LabCA interfaces between Matlab and EPICS (Experimental Physics and Industrial Control System). Such a system could speed development of commissioning required software and examine the correction of all procedures.
BNL, Upton, Long Island, New York
ANL, Argonne
A fundamental infrastructure of software framework for beam commissioning for NSLS-II storage ring is in development. It adopts client/server model, and consists of various servers for data communication and management. Based on this structure, some physics applications are developed to satisfy the requirements of day-1 beam commissioning. This paper describes our status of infrastructure development and its applications.
ANL, Argonne
The Advanced Photon Source (APS) real-time orbit feedback system is complex and faults are difficult to diagnose. This paper presents a diagnostic method based on fault tree analysis (FTA). The fault tree is created based on more than ten years operating experience of the system. The method is described to analyze the fault tree. The operator interface to the diagnostic tool is discussed.
PAL, Pohang, Kyungbuk
In the PLS-II storage ring, the available length of a long straight section for RF system is 6.28 m, which is from quadrupole magnet to quadrupole magnet beam-pipe valves with an elliptical transverse cross section. In this room, two beam-pipe transitions from elliptical to circle cross section, two commercial cryomodules with a circle transverse cross section, three bellows for adjusting cryomodule length and four vacuum valves could need to be installed. Two commercial cryomodules are too long to be installed into this section. In order to install two cryomodules into this section, we need to modify the tapers for reducing the total length of these parts. In this paper, the HOM damping effects for different taper shapes has been studied. The beam loss factor influence and broad-band impedance change due to taper shape changes have been estimated.
Muons, Inc, Batavia
CLASSE, Ithaca, New York
Superconducting RF (SRF) systems typically contain unwanted frequencies or higher order modes (HOM). For storage ring and linac applications, these higher modes must be damped by absorbing them in ferrite and other lossy ceramic materials. Typically, these absorbers are brazed to substrates that are strategically located, often in the drift tubes adjacent to the SRF cavity. These HOM loads must have broadband microwave loss characteristics and be robust both thermally and mechanically, but the ferrites and their attachments are weak under tensile and thermal stresses and tend to crack. Based on existing work on HOM loads for high current storage rings and for an ERL injector cryomodule, a HOM absorber with improved materials and design will be developed for high-gradient 750 MHz superconducting cavity systems for storage ring and linac radiation sources. This work will build on novel construction techniques to maintain the ferrite in mechanical compression without brazing. 750 MHz RF system designs will be numerically modeled to determine the optimum ferrite load required to meet broadband loss specifications.
Karlsruhe Institute of Technology (KIT), Karlsruhe
BNG, Würzburg
A 1.5 m long superconducting undulator with a period length of 15 mm is planned to be installed in ANKA middle 2010 to be the light source of the new beamline NANO for high resolution X-ray diffraction. The key specifications of the system are an undulator parameter K higher than 2 (for a magnetic gap of 5mm) and a phase error smaller than 3.5 degrees. In order to characterize the magnetic field properties of the superconducting coils local field measurements have been performed by moving a set of Hall probes on a sledge in a liquid helium bath: the results are reported.
MAX-lab, Lund
The MAX IV light source, presently under construction at MAX-lab in Lund, Sweden, will consist of two separate storage rings and a linac-driven short-pulse facility. The two storage rings are operated at different energies, 3 GeV and 1.5 GeV, to provide synchrotron radiation of high brightness over a broad spectral range. The 3 GeV linac serves as a full-energy injector for the storage rings as well as the driver of the short-pulse facility delivering intense x-ray pulses. The paper describes a selection of possible insertion devices to be installed at the MAX IV 3 GeV ring and the expected heat loads produced by the insertion devices.
NTHU, Hsinchu
NSRRC, Hsinchu
IUCF, Bloomington, Indiana
A novel gradient damping wiggler (GDW) was developed for the ALPHA storage ring in Indiana University. The GDW will be used to change the momentum compaction factor and the damping partition at ALPHA storage effectively. There is one middle pole and two outer poles that they have gradient field were assembled together on the same girder to be a full set of GDW magnet system. The dipole and gradient field strength of the middle (outer) pole is 0.67 T (-0.67) and 1.273 T/m (1.273 T/m), respectively. The magnet gap of the middle and outer pole is 40 mm and 35.87 mm, respectively, that the three combined function of dipole magnet can be charged by the same power supply. There is a trim coil on the three magnets to adjust the first and second integral field to zero. The good field region of middle pole and outer pole in transverse x-axis (deltaB/B=0.1%) are ±50mm and ±40mm separately. A prototype GDW magnet was fabricated and a Hall probe measurement system was set up to measure the magnet field to verify the magnet design and the magnet construction performance. The field cross-talk and the fringe field are also discussed herein by different methods.
Diamond, Oxfordshire
Diamond Light Source is currently operating with two multipole superconducting wigglers, one with 49 poles at 3.5 T and another with 49 poles at 4.2 T. The cryogenic arrangement is similar in both cases; each cryostat contains a liquid helium bath cooled by four cryocoolers. The design goal was to allow up to six months continuous operation in the storage ring between refilling the liquid helium bath. However, the helium boil-off is much higher than expected, necessitating much more frequent refills. As well as having a cost implication, this also currently poses a restriction on the operating beam current. In this report we present the results of measurements carried out under various beam conditions to try to understand the reason for the higher boil-off in terms of heat load seen by the cryostat and effective cryocooler performance. We also present our plans for dealing with the problem in the near and longer term.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
CITCEA-UPC, Barcelona
ALBA is a 3 GeV third generation synchrotron light source under construction in Spain. The design and performance of the ALBA Storage Ring Power Converters will be described. A total of 122 power converters are required: 1 for the dipoles (all connected in series), 112 for the quadrupoles (each magnets with its own power supply) and 9 for the sextupoles (each family connected in series). All converters are switched mode with full digital regulation and a common control interface. The paper will describe the performance of the power converters and compare it with the design specifications.
NSRRC, Hsinchu
The purpose of this paper is to estimate the conductive Electromagnetic Interference (EMI) from magnet power supply in NSRRC. A LISN system was conducted to measure the EMI spectrum of power supply. The different frequency range of conductive EMI was measured. For the future TPS(Taiwan Photon Source) power supply design, the EMI signals must be lower than TLS kicker. Therefore reducing and eliminating the interference of electromagnetic waves will be a very important issue. A filter and shielding method were used to test the effects of reducing EMI. The EMI prevention scheme will be used in the future.
NSRRC, Hsinchu
The Taiwan Photon Source (TPS), a third-generation synchrotron radiation light source, should be installed with 1032 sets of magnet power supplies for the storage ring and 152 sets for the injector. All of the power supplies are preferred in PWM switched mode with IGBT or MOSFET. A high precision DC power supply for 48 dipoles of the storage ring; there are 240 quadrupole magnets and 168 sextupole magnets in storage ring, the main winding of quadrupole and 168 sextupole magnets are powered by individual power supplies. In the booster ring, one set of dynamic power supply for the dipole magnets and four sets for quadrupole magnets run at the biased 3Hz quasi sinusoidal wave. There are several hundred corrector (fast and slow) magnets and skew quadrupole magnets in storage ring and injector are powered by the same bipolar power converters.
ANL, Argonne
The DC/DC converters in the Advanced Photon Source storage ring are more than 15 years old, and an upgrade is underway to resolve the aging and obsolescence issues. In the upgrade, an 18-bit resolution for current regulation is desired. This paper describes a digital control system to achieve this goal. The system uses a serializer chip, TI TLK2541, combined with a ∑-Δ modulator to realize a 21-bit digital pulse width modulation (DPWM). Analog and digital filters are implemented to block the ripple currents and to reduce the EMI noises. Deployed with filter circuits, a digital compensator has been designed to meet the requirements of output current regulation. Furthermore, a voltage feed forward is employed to compensate for input bus voltage variations. A prototype digital controller using a field-programmable-gate-array development board has been developed. The resolution of the current regulation, and the effect of noises into the digital controlled power converter system have been tested and analyzed.
BNL, Upton, Long Island, New York
By providing an extremely intense source of neutrinos from the decays of muons in a storage ring, a Neutrino Factory will provide the opportunity for precision measurements and searches for new physics amongst neutrino interactions. An active international collaboration is addressing the many technical challenges that must be met before the design for a Neutrino Factory can be finalized. An overview of the accelerator complex and the current international R&D program will be presented, and the key technical issues will be discussed.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The mechanical installation of the booster synchrotron of ALBA started in January 2009 and finished by having the system under vacuum in April 2009. The preparation of the booster vacuum system for the installation (partial assembly with the pumps and instrumentation, bakeout, etc) started already in September 2008. For the storage ring, the main mechanical installation was done from May to September 2009. The average pressure in the booster synchrotron is in the range of low 10-9 mbar and in the storage ring is in the low 10-10 mbar. The preparation of the installation, the installation and the present performance will be presented in this contribution. The first round of the booster commissioning took place at the end of 2009 and the beginning of 2010. The first data of the booster vacuum system commissioning are presented as well.
NSRRC, Hsinchu
Aluminum alloy was chosen for vacuum chamber materials and oil-free manufacturing, ozone water cleaning processes were used to obtain ultrahigh vacuum in TPS vacuum system. The storage ring vacuum system is divided into 24 unit cells and there are 6 ionized gauges, 8 ion pumps and 6 gate valves in one cell. An interlock system is designed to monitor and control the vacuum devices to keep ultrahigh vacuum. Because the vacuum chamber is exposed to the high power synchrotron radiation directly, cooling water and temperature statuses on the vacuum chamber are also monitored. The hardware, software and their associated interlock logic will be described.
LNLS, Campinas
In November 2010, LNLS plans to replace the two 50 kW UHF klystron valves which currently provides power to the RF cavities installed in the storage ring. Thanks to a close collaboration with the Syncrotron Soleil started in 1999, LNLS adapted the characteristics of the French project to 476 MHz. The choice of the transistor, the design of the combiners and details on power supplies will be reported, as well as the power tests performed with the two amplifiers using a resistive load.
NSRRC, Hsinchu
The design of the utility system for the 3.0 GeV Taiwan Photon Source (TPS) has been finished and the construction engineering has been contracted out in the end of 2009. This paper presents the TPS utility system, including the electrical power, cooling water and air conditioning system, which were designed to meet requirements of high reliability and stability. The TPS construction site is located adjacent to TLS. Even some areas of TPS and TLS are overlapped. The whole utility system construction will be finished in the end of 2012. Therefore, the construction engineering of the TPS utility system is a challenge to finish on a tight schedule and keep the TLS in operation during the construction. Some management schemes of the construction engineering are also presented in this paper.
NSRRC, Hsinchu
NTUT, Taipei
The stability of air temperature in the storage ring tunnel is one of the most critical factors. Therefore, a series of air conditioning system upgrade studies and projects have been conducted at the Taiwan Light Source (TLS). The global air temperature variation related to time in the storage ring tunnel has been controlled within ±0.1 degree C for years. This study is aimed at more precise temperature control. Some temperature control schemes are applied on this study. We also performed computational fluid dynamics (CFD) to simulate the flow field and the spatial temperature distribution in the storage ring tunnel.
NSRRC, Hsinchu
National Synchrotron Radiation Research Center (NSRRC) in Taiwan has finished an open bid about utility system for Taiwan photon source (TPS). The detail design and criteria of the utility cooling system, including cooling water and air conditioning system, have also been considered and confirmed. From controls to facility, all devices were designed and optimized to meet critical requirements of high reliability and stability. Besides, the paper mainly focuses on thermal load evaluation and removes to achieve the best efficiency and performance of system. The brand new system structure and control strategy also be realized.
NSC/KIPT, Kharkov
NESTOR facility that is under construction in NSC KIPT (Kharkov, Ukraine) consists of compact 225 MeV electron storage ring, 100 MeV linear accelerator-injector, laser optical system and radiation channel. To provide effective and cheap survey and alignment system for compact facility is crucial task in order to achieve designed X-ray parameters (X-ray intensity up to 1012 phot/s). In the article the survey and alignment strategy of Compton generator NESTOR is described. The system uses traditional triangulation method and provides the accuracy of technological equipment alignment equal to 100 mkm.
GSI, Darmstadt
CERN, Geneva
In the complex of the accelerators of the FAIR project the RESR storage ring is mainly designed as an accumulator ring for antiprotons. The continuous accumulation of pre-cooled batches with a cycle time of 10 s from the collector ring is essential to achieve the goal of a production rate of 10 million antiprotons per second. The accumulation in the RESR uses a stochastic cooling system which operates in longitudinal phase space, similar as previous antiproton accumulator rings at CERN and FNAL. The ingredients of the accumulation system, the ring lattice functions, the electrode design and the electrical circuits have been studied in detailed simulations. A system has been found which safely provides the required performance and offers the option of upgrades, if higher accumulation rate is required in future. Maximum intensities of 100 billion cooled antiprotons are planned which are expected to stay below the instability threshold.
IAP, Frankfurt am Main
The stellarator-type storage ring for multi- Ampere proton and ion beams with energies in the range of 100 AkeV to 1AMeV was designed. The main idea for beam confinement with high transversal momentum acceptance was presented in EPAC06 and EPAC08. Stable beam transport in opposite directions is possible through the same aperture with two crossing points along the structure. Elsewhere the beams are separated by the RxB drift motion in curved sections. The space charge compensation through the trapped or circulated electrons will be discussed. This ring is typically suited for experiments in plasma physics and nuclear astrophysics. Here we present the complete simulations for optimization of ring geometry, a stable beam confinement and developments in beam injection.
NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
A simple analytical formula for the transient bunch lengthening by betatron motion along bending sections is explained. The formula describes a longitudinal and transverse coupling for a single-pass line, which is obtained as an extension of the formula for a storage ring. The bunch lengthening is expressed by a product of three factors: the square root of horizontal betatron emittance, a betatron phase factor, and the square root of the H-function, in other words, dispersion action. That effect had been calculated in many reports concerning with sub-ps electron bunch generation, such as the laser-bunch slicing, the vertical bunch deflection by a crab cavity, and the beam transport along a quasi-isochronous bending arcs. In these works the transfer matrix elements, R15 and R25, had been calculated for each of various conditions. On the contrary, our simple and general analytical formula gives a good foresight to understand the observed phenomena and for an easy optimization of parameters of bending arcs.
KEK, Ibaraki
IHEP Beijing, Beijing
A perturbation method based on Lie technique, originated by J. Irwin and C.-x. Wang, was extended to calculate the linear maps for the fringe field of a quadrupole. In our method, the fringe field shape is not necessarily anti-symmetric with respect to the hard-edge position. The linear maps were explicitly expressed as functions of fringe field integrals. Thus they can be used to assess the influence of the quadrupole fringe fields in beam dynamics.
USTC/NSRL, Hefei, Anhui
Low emittance is a desirable performance for high brightness synchrotron light source and damping ring. The work presented in this paper demonstrates that the lattice of a given electron storage ring, which has fixed circumference and magnet layout, can be optimized to obtain low emittance by using MOGA (Multi-objective Genetic Algorithm). Both dispersion-free and non-dispersion-free lattices of HLS (Hefei Light Source) upgrade project are computed as an illustration. Simulation result shows that this method is fast and straightforward.
USTC/NSRL, Hefei, Anhui
In order to meet the increasing requirements of synchrotron radiation users, an upgrading plan of hefei light source is undergoing by National Synchrotron Radiation Laboratory (NSRL). The emittance of storage ring is reduced from 166nm.rad to 36nm.rad. In this paper, we study the beam close orbit distortions' (COD) sensitivity to the field and alignment errors in magnets. Estimation of the COD from various error sources is investigated. The distribution of beam position monitors and the location of correctors are reported in the paper. Simulation proves that COD can be corrected down to 50 microns level. In the same time the corrector strengths are weaker enough in the correction scheme.
USTC/NSRL, Hefei, Anhui
To enhance the performance of Hefei Light Source, an upgrade project is undergoing. The magnet lattice of storage ring will be reconstructed with 4 DBA cells, whose advantages are lower beam emittance and more straight section available for insertion devices. In order to assure smooth beam accumulation process under new low emittance lattice, the injector, which is composed of electron linac and beam transfer line, would be updated. The detail of upgrading Hefei Light Source transport line will be described in this paper. It include the upgrading of lattice, the orbit control of beam transfer line and others. It is hopeful to realize a high transfer efficiency and high injection efficiency for new lower beam emittance storage ring.
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is the second synchrotron light source in Taiwan which is currently under construction at the NSRRC existing site. With a 3 GeV beam energy, low emittance, 24-DB structure in the storage ring, the TPS can generate higher brilliance and more abundant X-ray sources. TPS is in complementary to the overbooked 1.5 GeV Taiwan Light Source (TLS). The MATLAB-based accelerator physics application programs planned for the TPS commissioning and operation is a high-level software collection including the MML, AT, LOCO, etc., developed at ALS and SLAC. In this report, the testing results by employing this package to the Taiwan Light Source (TLS) are given and the simulations of the TPS virtual machine are also demonstrated.
Diamond, Oxfordshire
JAI, Oxford
The Diamond storage ring has been operated in low alpha mode providing short-pulse radiation for pump-probe experiments and coherent radiation for THz/IR measurements. Two lattices have been implemented, with both capable of providing a variable alpha in the range ±2x10-5, down to minimum values well below 1x10-6. The second lattice additionally provides a low emittance of 4nm.rad, compared to 35nm.rad for the first lattice. An overview of operation in low alpha mode is given, along with first measurements of coherent emission at long wavelengths under a variety of conditions.
ANL, Argonne
IHEP Beijing, Beijing
Nonuniform dipoles with bending field variation have been studied for reducing storage ring emittance in recent years. According to a new minimum emittance theory, the effects of an arbitrary dipole can be characterized by two parameters. To have a better idea of the potentials of nonuniform dipoles, here we numerically explore the values of these two parameters for optimal emittance reduction.
CANDLE, Yerevan
A method of beam energy spread and synchrotron tune measurements based on the analysis of transverse decoherence\recoherence signal of kicked beam is presented. As an illustration the beam energy spread was extracted for the SLS storage ring.
JASRI/SPring-8, Hyogo-ken
The dynamic aperture is of importance for high injection efficiency and long lifetime of a storage ring. At the SPring-8 storage ring, a third generation light source facility, various improvements of the dynamic aperture were developed, e.g. the introduction of supplemental sextupole magnets at long straight sections, and the symmetry restoration of linear lattice. To understand the nonlinear dynamics limiting the aperture, the measurements were performed for the various operation conditions with the improvements. Using injection bump magnets and turn-by-turn beam position monitor system, we measured the horizontal dynamic aperture. The Fourier analysis of the oscillation of the kicked beam shows the resonance excitation influential on the dynamic aperture. The knowledge through the experiments is essential to the further improvements of the dynamic aperture of the present ring and the new storage ring design of the future SPring-8 upgrades.
PAL, Pohang, Kyungbuk
A superconducting RF cavity is used in the storage ring of the Pohang Light Source (PLS) upgrade project (PLS-II) at Pohang Accelerator Laboratory (PAL) for increasing the electron beam current and energy from 2.5GeV/200mA to 3.0GeV/400mA. In order to meet the requirement of lower beam emittance and higher photon energies, as well as more straight sections for insertion devices, the vacuum chambers in the storage ring need to be reconstructed. To control the spurious harmonic resonances' effect to beam position monitors (BPMs) in the PLS and PLS-II storage ring vacuum chamber, the TE mode distribution in vacuum chambers has been analyzed by both numerical simulation and experiment. Based on this analysis, the proper method to control the strength of TE mode at the position of BPMs is suggested.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The high order magnetic multipole components of all the magnets in the ALBA storage ring have been measured. Previous studies have simulated the effects of the HOMs using statistic methods. The magnets have been installed now in the tunnel, allowing for a better simulation of the future impact of the HOMs in the performance of the light source. In this paper, the effect of the high order multipoles of the dipole, quadrupole and sextupole magnets in the dynamic aperture and the Touschek lifetime are reviewed.
Diamond, Oxfordshire
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin
JAI, Oxford
CERN, Geneva
The correct implementation of the nonlinear ring model is crucial to achieve the top performance of a synchrotron light source. Several dynamics quantities can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these methods are based on the analysis of turn-by-turn data of excited betatron oscillations. We present the experimental results of the campaign of measurements carried out at the Diamond. A combination of Frequency Map Analysis and resonant driving terms measurements has allowed a precise calibration of the nonlinear model capable of reproducing and then correcting the nonlinear beam dynamics in the storage ring.
ANL, Argonne
APS linear model is defined by the quadrupole and skew quadrupole errors that are determined using the response matrix fit. What was missing until now were the sextupole offsets relative to the beam orbit. At APS the orbit is routinely steered according to user requests, and at some locations the steering has accumulated to rather large values. That is why the usual sextupole changes that are performed during operation mode switches lead to optics and coupling changes. Knowledge of the sextupole offsets would allow us to predict and control those changes. There are a number of ways to measure sextupole offsets but most of them utilize element by element approach. This would take very long time for the 280 sextupoles at APS. Here we describe a method that determines the beam offsets of all sextupoles based on fitted values of local optics and coupling changes at each sextupole. We perform response matrix measurement, fit several lattices with different sextupoles, and derive the sextupole offsets. The results are included in the linear model of the APS storage ring.