The phase slip factor of the electrostatic cryogenic storage ring CSR

NASA Astrophysics Data System (ADS)

Grieser, Manfred; von Hahn, Robert; Vogel, Stephen; Wolf, Andreas

2017-07-01

To determine the momentum spread of an ion beam from the measured revolution frequency distribution, the knowledge of the phase slip factor of the storage ring is necessary. The slip factor was measured for various working points of the cryogenic storage ring CSR at MPI for Nuclear Physics, Heidelberg and was compared with simulations. The predicted functional relationship of the slip factor and the horizontal tune depends on the different islands of stability, which has been experimentally verified. This behavior of the slip factor is in clear contrast to that of magnetic storage rings.

Total water storage dynamics derived from tree-ring records and terrestrial gravity observations

NASA Astrophysics Data System (ADS)

Creutzfeldt, Benjamin; Heinrich, Ingo; Merz, Bruno

2015-10-01

For both societal and ecological reasons, it is important to understand past and future subsurface water dynamics but estimating subsurface water storage is notoriously difficult. In this pilot study, we suggest the reconstruction of subsurface water dynamics by a multi-disciplinary approach combining hydrology, dendrochronology and geodesy. In a first step, nine complete years of high-precision gravimeter observations are used to estimate water storage changes in the subsurface at the Geodetic Observatory Wettzell in the Bavarian Forest, Germany. The record is extended to 63 years by calibrating a hydrological model against the 9 years of gravimeter observations. The relationship between tree-ring growth and water storage changes is evaluated as well as that between tree-ring growth and supplementary hydro-meteorological data. Results suggest that tree-ring growth is influenced primarily by subsurface water storage. Other variables related to the overall moisture status (e.g., Standardized Precipitation Index, Palmer Drought Severity Index, streamflow) are also strongly correlated with tree-ring width. While these indices are all indicators of water stored in the landscape, water storage changes of the subsurface estimated by depth-integral measurements give us the unique opportunity to directly reconstruct subsurface water storage dynamics from records of tree-ring width. Such long reconstructions will improve our knowledge of past water storage variations and our ability to predict future developments. Finally, knowing the relationship between subsurface storage dynamics and tree-ring growth improves the understanding of the different signal components contained in tree-ring chronologies.

Coupled beam motion in a storage ring with crab cavities

DOE PAGES

Huang, Xiaobiao

2016-02-16

We studied the coupled beam motion in a storage ring between the transverse and longitudinal directions introduced by crab cavities. Analytic form of the linear decoupling transformation is derived. Also, the equilibrium bunch distribution in an electron storage ring with a crab cavity is given, including contribution to the eigen-emittance induced by the crab cavity. Furthermore, application to the short pulse generation scheme using crab cavities [1] is considered.

Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

NASA Astrophysics Data System (ADS)

Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

2012-04-01

Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily

Single-pass BPM system of the Photon Factory storage ring.

PubMed

Honda, T; Katoh, M; Mitsuhashi, T; Ueda, A; Tadano, M; Kobayashi, Y

1998-05-01

At the 2.5 GeV ring of the Photon Factory, a single-pass beam-position monitor (BPM) system is being prepared for the storage ring and the beam transport line. In the storage ring, the injected beam position during the first several turns can be measured with a single injection pulse. The BPM system has an adequate performance, useful for the commissioning of the new low-emittance lattice. Several stripline BPMs are being installed in the beam transport line. The continuous monitoring of the orbit in the beam transport line will be useful for the stabilization of the injection energy as well as the injection beam orbit.

Dose estimates for the 1104 m APS storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, H.J.

1989-06-01

The estimated dose equivalent rates outside the shielded storage ring, and the estimated annual dose equivalent to members of the public due to direct radiation and skyshine from the ring, have been recalculated. The previous estimates found in LS-84 (MOE 87) and cited in the 1987 Conceptual Design Report of the APS (ANL 87) required revision because of changes in the ring circumference and in the proposed location of the ring with respect to the nearest site boundary. The values assumed for the neutron quality factors were also overestimated (by a factor of 2) in the previous computation, and themore » correct values have been used for this estimate. The methodology used to compute dose and dose rate from the storage ring is the same as that used in LS-90 (MOE 87a). The calculations assumed 80 cm thick walls of ordinary concrete (or the shielding equivalent of this) and a roof thickness of 1 meter of ordinary concrete. The circumference of the ring was increased to 1,104 m, and the closest distance to the boundary was taken as 140 m. The recalculation of the skyshine component used the same methodology as that used in LS-84.« less

The KACST Heavy-Ion Electrostatic Storage Ring

NASA Astrophysics Data System (ADS)

Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.; Papash, A. I.; Welsch, C. P.

2011-10-01

A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The development of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.

The KACST Heavy-Ion Electrostatic Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.

2011-10-27

A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The developmentmore » of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.« less

Study of Storage Ring Free-Electron Laser Using Experimental and Simulation Approaches

NASA Astrophysics Data System (ADS)

Jia, Botao

2011-12-01

The Duke electron storage ring, first commissioned in November of 1994, has been developed as a dedicated driver for storage ring free-electron lasers (SRFELs) operating in a wide wavelength range from infrared, to visible, to ultraviolet (UV) and vacuum ultraviolet (VUV). The storage ring has a long straight section for various insertion devices and can be operated in a wide energy range (0.25 GeV to 1.15 GeV). Commissioned in 1995, the first free-electron laser (FEL) on the Duke storage ring was the OK-4 FEL, an optical klystron with two planar undulators sandwiching a buncher magnet. In 2005, the OK-5 FEL with two helical undulators was commissioned. Operating four undulators---two OK-4 and two OK-5 undulators, the world's first distributed optical klystron FEL was brought to operation in 2005. Via Compton scattering of FEL photons and electrons in the storage ring, the Duke FEL drives the world's most powerful, nearly monochromatic, and polarized Compton gamma-ray source, the High Intensity Gamma-ray Source (HIgammaS). Today, a variety of configurations of the storage ring FELs at Duke have been used in a wide range of research areas from nuclear physics to biophysics, from chemical and medical research to industrial applications. The capability of accurately measuring the storage ring electron beam energy spread is crucial for understanding the longitudinal beam dynamics and the dynamics of the storage ring FEL. In this dissertation, we have successfully developed a noninvasive, versatile, and accurate method to measure the energy spread using optical klystron radiation. Novel numerical methods based upon the Gauss-Hermite expansion have been developed to treat both spectral broadening and modulation on an equal footing. Through properly configuring the optical klystron, this energy spread measurement method has a large dynamic range. In addition, a model-based scheme has been developed for correcting the electron beam emittance related inhomogeneous spectral

Status of the Frankfurt low energy electrostatic storage ring (FLSR)

NASA Astrophysics Data System (ADS)

King, F.; Kruppi, T.; Müller, J.; Dörner, R.; Schmidt, L. Ph H.; Schmidt-Böcking, H.; Stiebing, K. E.

2015-11-01

Frankfurt low-energy storage ring (FLSR) is an electrostatic storage ring for low-energy ions up to q · 80 keV (q being the ion charge state) at Institut für Kernphysik der Goethe-Universität, Frankfurt am Main, Germany. It has especially been designed to provide a basis for experiments on the dynamics of ionic and molecular collisions in complete kinematics, as well as for high precision and time resolved laser spectroscopy. The ring has ‘racetrack’ geometry with a circumference of 14.23 m. It comprises four experimental/diagnostic sections with regions of enhanced ion density (interaction regions). First beam has successfully been stored in FLSR in summer 2013. Since then the performance of the ring has continuously been improved and an electron target for experiments on dissociative recombination has been installed in one of the experimental sections.

Future Synchrotron Light Sources Based on Ultimate Storage Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Yunhai; /SLAC

2012-04-09

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving anmore » ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic

The Abort Kicker System for the PEP-II Storage Rings at SLAC.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delamare, Jeffrey E

2003-06-20

The PEP-II project has two storage rings. The HER (High Energy Ring) has up to 1.48 A of election beam at 9 GeV, and the LER (Low Energy Ring) has up to 2.14 A of positron beam at 3.1 GeV. To protect the HER and LER beam lines in the event of a ring component failure, each ring has an abort kicker system which directs the beam into a dump when a failure is detected. Due to the high current of the beams, the beam kick is tapered from 100% to 80% in 7.33 {micro}S (the beam transit time aroundmore » the ring). This taper distributes the energy evenly across the window which separates the ring from the beam dump such that the window is not damaged. The abort kicker trigger is synchronized with the ion clearing gap of the beam allowing for the kicker field to rise from 0-80% while there is no beam in the kicker magnet. Originally the kicker system was designed for a rise time of 370nS [1], but because the ion clearing gap was reduced in half, so was the rise time requirement for the kicker. This report discusses the design of the system interlocks, diagnostics, and modulator with the modifications necessary to accommodate an ion clearing gap of 185nS.« less

Feasibility of maintaining in-plane polarization for a storage ring EDM search

NASA Astrophysics Data System (ADS)

Stephenson, Edward; Storage Ring EDM Collaboration

2014-09-01

A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron cooling reduces the depolarization from finite emittance and second-order momentum spread acting through synchrotron oscillations. Further lifetime improvement to the level of hundreds of seconds is achieved by adjusting sextupole fields located in the COSY ring arcs at places of large transverse beta functions and dispersion. The dependence of the reciprocal of the lifetime on sextupole field strength is nearly linear, permitting an easy location of the best field values. These typically occur near loci of zero chromaticity. A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron

Compact Storage Ring for an X-Ray Source

NASA Astrophysics Data System (ADS)

Ovchinnikova, L.; Shvedunov, V.; Ivanov, K.

2017-12-01

We propose a new design of a compact storage ring for a source of X-ray radiation on the basis of reverse Thomson scattering of laser radiation by electrons with the energy of 35-50 MeV, which has small number of optical elements and a significant clear space for the placement of a beam injection-extraction system and a RF cavity. The original laser cavity layout has been considered. The ring dynamic aperture after correction of chromaticity and a second-order dispersion function is sufficient for the injection and stable circulation of an electron bunch in the ring.

A Model Describing Stable Coherent Synchrotron Radiation in Storage Rings

NASA Astrophysics Data System (ADS)

Sannibale, F.; Byrd, J. M.; Loftsdóttir, Á.; Venturini, M.; Abo-Bakr, M.; Feikes, J.; Holldack, K.; Kuske, P.; Wüstefeld, G.; Hübers, H.-W.; Warnock, R.

2004-08-01

We present a model describing high power stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), which enhances higher frequency coherent emission, and limits to stable emission due to an instability excited by the SR wakefield. It gives a quantitative explanation of several features of the recent observations of CSR at the BESSYII storage ring. We also use this model to optimize the performance of a source for stable CSR emission.

Beam vacuum system of Brookhaven`s muon storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hseuth, H.C.; Snydstrup, L.; Mapes, M.

1995-11-01

A storage ring with a circumference of 45 m is being built at Brookhaven to measure the g-2 value of the muons to an accuracy of 0.35 ppm.. The beam vacuum system of the storage ring will operate at 10{sup -7} Torr and has to be completely non-magnetic. It consists of twelve sector chambers. The chambers are constructed of aluminum and are approximately 3.5 m in length with a rectangular cross-section of 16.5 cm high by 45 cm at the widest point. The design features, fabrication techniques and cleaning methods for these chambers are described. The beam vacuum system willmore » be pumped by forty eight non-magnetic distributed ion pumps with a total pumping speed of over 2000 {ell}/sec. Monte Carlo simulations of the pressure distribution in the muon storage region are presented.« less

Planning and Prototyping for a Storage Ring Measurement of the Proton Electric Dipole Moment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talman, Richard

2015-07-01

Electron and proton EDM's can be measured in "frozen spin" (with the beam polarization always parallel to the orbit, for example) storage rings. For electrons the "magic" kinetic energy at which the beam can be frozen is 14.5 MeV. For protons the magic kinetic energy is 230 MeV. The currently measured upper limit for the electron EDM is much smaller than the proton EDM upper limit, which is very poorly known. Nevertheless, because the storage ring will be an order of magnitude cheaper, a sensible plan is to first build an all-electric electron storage ring as a prototype. Such anmore » electron ring was successfully built at Brookhaven, in 1954, as a prototype for their AGS ring. This leaves little uncertainty concerning the cost and performance of such a ring. (This is documentedin one of the Physical Review papers mentioned above.)« less

Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, C.; Qiang, J.; Venturini, M.

The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailingmore » magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.« less

The cryogenic storage ring CSR

NASA Astrophysics Data System (ADS)

von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

2016-06-01

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

The cryogenic storage ring CSR.

PubMed

von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

2016-06-01

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

Fluorescence decay of naphthalene studied in an electrostatic storage ring, the Mini-Ring

NASA Astrophysics Data System (ADS)

Martin, S.; Matsumoto, J.; Kono, N.; Ji, M.-C.; Brédy, R.; Bernard, J.; Cassimi, A.; Chen, L.

2017-10-01

The cooling of naphthalene cations (C10H8)+ has been studied in a compact electrostatic ion storage ring, the Mini-Ring. A nano second laser pulse of 532 nm (2.33 eV) was used to probe the internal energy distribution every millisecond during the storage time up to 5 ms. The evolution of the internal energy distribution of the stored ions was simulated with a model taking into account the dissociation and the radiative decay processes. Calculated decay curves were fitted to the corresponding laser induced neutral decays. For a laser power of 200 μJ/pulse, a good agreement between experiment and modeling was found using an initial Gaussian energy distribution centered to 5.9 eV and a fluorescence decay rate varying from 200 to 300 s-1 in the energy range from 6 to 7 eV. This fast decay was attributed to the delayed Poincaré fluorescence process.

Design of the transfer line from booster to storage ring at 3 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayar, C., E-mail: cafer.bayar@cern.ch; Ciftci, A. K., E-mail: abbas.kenan.ciftci@cern.ch

The Synchrotron Booster Ring accelerates the e-beam up to 3 GeV and particles are transported from booster to storage ring by transfer line. In this study, two options are considered, the first one is a long booster which shares the same tunnel with storage ring and the second one is a compact booster. As a result, two transfer line are designed based on booster options. The optical design is constrained by the e-beam Twiss parameters entering and leaving the transfer line. Twiss parameters in the extraction point of booster are used for the entrance of transfer line and are matchedmore » in the exit of transfer line to the injection point of the storage ring.« less

Ring profiler: a new method for estimating tree-ring density for improved estimates of carbon storage

Treesearch

David W. Vahey; C. Tim Scott; J.Y. Zhu; Kenneth E. Skog

2012-01-01

Methods for estimating present and future carbon storage in trees and forests rely on measurements or estimates of tree volume or volume growth multiplied by specific gravity. Wood density can vary by tree ring and height in a tree. If data on density by tree ring could be obtained and linked to tree size and stand characteristics, it would be possible to more...

Simulation of emittance dilution in electron storage ring from Compton backscattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumberg, L.N.; Blum, E.

1993-07-01

A Monte-Carlo simulation of Compton backscattered {kappa}{sub L}=3.2-{mu}m photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of {Delta}{sub E}=11.9-keV for a sample of 10{sup 7} single scattering events. Electrons are sampled from a beam of natural energy spread {sigma}{sub E} = 5.6-keV and damped transverse angle spreads {sigma}{sub x}{prime}, = .041-mrad and {sigma}{sub y}{prime} = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered X-Rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performedmore » in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads {sigma}{sub xo}=.102-mm, {sigma}{sub x{prime}o}=.041-mrad, {sigma}{sub yo}=.018-mm, {sigma}{sub y{prime}o}=.052-mrad, {sigma}{sub {phi}o}=22-mrad and {sigma}{sub Eo}=6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of f{sub rf}=211.54-MHz and peak voltage V{sub m}=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of {Delta}{sub E} = 124-keV. The transverse widths are only slightly increased from their original values, i.e. {Delta}{sub x} = .106-mm and {Delta}{sub x}{prime}=.043 mrad. The scaled energy spread of {Delta}{sub E} {approximately} 360-keV for {approximately} 350,000 turns desired in a 10-msec X-Ray angiography exposure is well within the RF bucket used here; even V{sub m} < 50-kV is adequate. Further, the electron energy spread adds a negligible RMS X-Ray energy spread of {Delta}{sub Ex}=.32-keV. The electron energy damping time of {tau}{sub E}=379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off of the ring between heart cycles.« less

Simulation of emittance dilution in electron storage ring from Compton backscattering

NASA Astrophysics Data System (ADS)

Blumberg, L. N.; Blum, E.

A Monte-Carlo simulation of Compton backscattered kappa(sub L) = 3.2-micron photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of delta(sub E) = 11.9-keV for a sample of 10(exp 7) single scattering events. Electrons are sampled from a beam of natural energy spread sigma(sub E) = 5.6-keV and damped transverse angle spreads sigma(sub x)(prime) = .041-mrad and sigma(sub y)(prime) = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered x-rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performed in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads sigma(sub xo) = .102-mm, sigma(sub x(prime)o) = .041-mrad, sigma(sub yo) = .018-mm, sigma(sub y(prime)o) = .052-mrad, sigma(sub (phi)o) = 22-mrad and sigma(sub Eo) = 6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of f(sub RF) = 211.54-MHz and peak voltage V(sub m)=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of delta(sub E) = 124-keV. The transverse widths are only slightly increased from their original values, i.e. delta(sub x) = .106-mm and delta(sub x)(prime) = .043 mrad. The scaled energy spread of delta(sub E) approximately = 360-keV for approximately 350,000 turns desired in a 10-msec x-ray angiography exposure is well within the RF bucket used here; even V(sub m) less than 50-kV is adequate. Further, the electron energy spread adds a negligible RMS x-ray energy spread of delta(sub Ex) = .32-keV. The electron energy damping time of tau(sub E) = 379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off of the ring between heart cycles.

The Tunguska event in 1908: evidence from tree-ring anatomy.

PubMed

Vaganov, Evgenii A; Hughes, Malcolm K; Silkin, Pavel P; Nesvetailo, Valery D

2004-01-01

We analyzed tree rings in wood samples collected from some of the few surviving trees found close to the epicenter (within 4-5 km) of the Tunguska event that occurred on the last day of June 1908. Tree-ring growth shows a depression starting in the year after the event and continuing during a 4-5-year period. The most remarkable traces of the event were found in the rings' anatomical structure: (1) formation of "light" rings and a reduction of maximum density in 1908; (2) non-thickened tracheids (the cells that make up most of the wood volume) in the transition and latewood zones (the middle and last-formed parts of the ring, respectively); and (3) deformed tracheids, which are located on the 1908 annual ring outer boundary. In the majority of samples, normal earlywood and latewood tracheids were formed in all annual rings after 1908. The observed anomalies in wood anatomy suggest two main impacts of the Tunguska event on surviving trees--(1) defoliation and (2) direct mechanical stress on active xylem tissue. The mechanical stress needed to fell trees is less than the stress needed to cause the deformation of differentiating tracheids observed in trees close to the epicenter. In order to resolve this apparent contradiction, work is suggested on possible topographic modification of the overpressure experienced by these trees, as is an experimental test of the effects of such stresses on precisely analogous growing trees.

EUTERPE, a small electron storage ring for XRF

NASA Astrophysics Data System (ADS)

Botman, J. I. M.; Mutsaers, P. H. A.; Hagedoorn, H. L.; De Voigt, M. J. A.

1990-04-01

A small-sized electron storage ring is under construction at the Eindhoven University of Technology which will cover the energy range of 15 to 400 MeV. At top energy the characteristic wavelength of the synchrotron radiation spectrum is 8.3 nm for the regular dipole magnets and 1.2 nm corresponding to 1.06 keV for a 10 T wiggler magnet. This will provide useful radiation for X-ray fluorescence (XRF) up to 3.2 keV. Alternatively, photon conversion with a high power CO 2 laser beam of 0.124 eV photons will generate X-rays for XRF with energies ranging from 0.5 to 300 keV, depending on the operating energy of the storage ring. This facility will provide an important extension to the activities of the Eindhoven group on PIXE, RBS and microbeam analysis. A short description of the macnine will be given together with applications and specific examples of the XRF method.

Constrained multi-objective optimization of storage ring lattices

NASA Astrophysics Data System (ADS)

Husain, Riyasat; Ghodke, A. D.

2018-03-01

The storage ring lattice optimization is a class of constrained multi-objective optimization problem, where in addition to low beam emittance, a large dynamic aperture for good injection efficiency and improved beam lifetime are also desirable. The convergence and computation times are of great concern for the optimization algorithms, as various objectives are to be optimized and a number of accelerator parameters to be varied over a large span with several constraints. In this paper, a study of storage ring lattice optimization using differential evolution is presented. The optimization results are compared with two most widely used optimization techniques in accelerators-genetic algorithm and particle swarm optimization. It is found that the differential evolution produces a better Pareto optimal front in reasonable computation time between two conflicting objectives-beam emittance and dispersion function in the straight section. The differential evolution was used, extensively, for the optimization of linear and nonlinear lattices of Indus-2 for exploring various operational modes within the magnet power supply capabilities.

Stochastic events may lead to accretion in Saturn's rings

NASA Astrophysics Data System (ADS)

Esposito, Larry W.

Stochastic events may lead to accretion in Saturn's rings Larry W. Esposito LASP, University of Colorado UVIS occultations indicate accretion is triggered at the B ring edge, in strong density waves in ring A and in the F ring. Moons may trigger accretion by streamline crowding (Lewis & Stewart); which enhances collisions, leading to accretion; increasing random velocities; leading to more collisions and more accretion. Cassini occultations of these strongly perturbed locations show not only accretion but also disaggregation, with time scales of hours to weeks. The collisions may lead to temporary aggregations via stochastic events: collisions can compress unconsolidated objects, trigger adhesion or bring small pieces into contact with larger or higher-density seeds. Disaggregation then can follow from disruptive collisions or tidal shedding. In the accretion/disruption balance, increased random motions could eventually give the upper hand to disruption. . . just as `irrational exuberance' can lead to financial panic in the economy; or the overpopulation of hares can lead to boom-and-bust in the population of foxes. I present a simple predator-prey model. This system's unstable equilibrium can similarly give rise to episodic cycles in accretion: explaining why the observable ring features that indicate embedded objects have been increasing since the beginning of Cassini's observations of Saturn in 2004. Unlike other interpretations of the peculiar events seen near Saturn Equinox, I emphasize the kinetic description of particle interactions rather than a fluid instability approach; and the dominance of stochastic events involving individual aggregates over free and/or driven modes in a flat disk.

Low-emittance tuning of storage rings using normal mode beam position monitor calibration

NASA Astrophysics Data System (ADS)

Wolski, A.; Rubin, D.; Sagan, D.; Shanks, J.

2011-07-01

We describe a new technique for low-emittance tuning of electron and positron storage rings. This technique is based on calibration of the beam position monitors (BPMs) using excitation of the normal modes of the beam motion, and has benefits over conventional methods. It is relatively fast and straightforward to apply, it can be as easily applied to a large ring as to a small ring, and the tuning for low emittance becomes completely insensitive to BPM gain and alignment errors that can be difficult to determine accurately. We discuss the theory behind the technique, present some simulation results illustrating that it is highly effective and robust for low-emittance tuning, and describe the results of some initial experimental tests on the CesrTA storage ring.

Beam Loss Measurements at the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Spickermann, Thomas

2005-06-01

During normal operation the Los Alamos Proton Storage Ring (PSR) accumulates up to 4ṡ1013 protons over 625μs with a repetition rate of 20 Hz, corresponding to a current of 125μA to the Lujan Neutron Science Center. Beam losses in the ring as well as in the extraction beam line and the subsequent activation of material are a limiting factor at these currents. Careful tuning of injection, ring and extraction line is paramount to limiting losses to acceptable levels. Losses are typically not uniform around the ring, but occur in significantly higher levels in certain "hot spots". Here I will report on losses related to the stripper foil which are the dominant source of losses in the ring. First results of a comparison with simulations will also be presented.

Storage rings for spin-polarized hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, D.; Lovelace, R.V.E.; Lee, D.

1989-11-01

A strong-focusing storage ring is proposed for the long-term magnetic confinement of a collisional gas of neutral spin-polarized hydrogen atoms in the Za{l arrow} and Zb{l arrow} hyperfine states. The trap uses the interaction of the magnetic moments of the gas atoms with a static magnetic field. Laser cooling and evaporative cooling can be utilized to enhance the confinement and to offset the influence of viscous heating. An important application of the trap is to the attainment of Bose--Einstein condensation.

High resolution monochromator for the VUV radiation from the DORIS storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saile, V.; Gurtler, P.; Koch, E.E.

1976-10-01

The unique properties of the DORIS storage ring at DESY as a synchroton radiation source are exploited for high resolution spectroscopy in the vacuum ultraviolet. We describe a new experimental set up with a 3-m normal incidence monochromator for wavelengths between 3000 A and 300 A (4 < or = h..omega.. < or = 40 eV) using a vertical dispersion plane. The storage ring provides a light flux intense and stable enough for rapid photoelectrical scanning of the spectra with a resolution of 0.03 A in first order. (AIP)

Feasibility of a ring FEL at low emittance storage rings

NASA Astrophysics Data System (ADS)

Agapov, I.

2015-09-01

A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500-1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

ACCELERATORS: Beam based alignment of the SSRF storage ring

NASA Astrophysics Data System (ADS)

Zhang, Man-Zhou; Li, Hao-Hu; Jiang, Bo-Cheng; Liu, Gui-Min; Li, De-Ming

2009-04-01

There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.

Symplectic orbit and spin tracking code for all-electric storage rings

NASA Astrophysics Data System (ADS)

Talman, Richard M.; Talman, John D.

2015-07-01

Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring "trap." At the "magic" kinetic energy of 232.792 MeV, proton spins are "frozen," for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10-29e -cm or greater will produce a statistically significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial "symplectification"). Any residual spurious damping or antidamping is sufficiently small to permit reliable tracking for the

Colliding or co-rotating ion beams in storage rings for EDM search

NASA Astrophysics Data System (ADS)

Koop, I. A.

2015-11-01

A new approach to search for and measure the electric dipole moment (EDM) of the proton, deuteron and some other light nuclei is presented. The idea of the method is to store two ion beams, circulating with different velocities, in a storage ring with crossed electric and magnetic guiding fields. One beam is polarized and its EDM is measured using the so-called ‘frozen spin’ method. The second beam, which is unpolarized, is used as a co-magnetometer, sensitive to the radial component of the ring’s magnetic field. The particle’s magnetic dipole moment (MDM) couples to the radial magnetic field and mimics the EDM signal. Measuring the relative vertical orbit separation of the two beams, caused by the presence of the radial magnetic field, one can control the unwanted MDM spin precession. Examples of the parameters for EDM storage rings for protons and other species of ions are presented. The use of crossed electric and magnetic fields helps to reduce the size of the ring by a factor of 10-20. We show that the bending radius of such an EDM storage ring could be about 2-3 m. Finally, a new method of increasing the spin coherence time, the so-called ‘spin wheel’, is proposed and its applicability to the EDM search is discussed.

Intra-Beam Scattering, Impedance, and Instabilities in Ultimate Storage Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bane, Karl; /SLAC

We have investigated collective effects in an ultimate storage ring, i.e. one with diffraction limited emittances in both planes, using PEP-X as an example. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, a 4.5 GeV ring running round beams at 200 mA in 3300 bunches, IBS doubles the emittances to 11.5 pm at the design current. The Touschek lifetime is 11 hours. Impedance driven collective effects tend not to be important since the beam current is relatively low. We have investigated collective effects in PEP-X, an ultimate storage ring, i.e.more » one with diffraction limited emittances (at one angstrom wavelength) in both planes. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, IBS doubles the emittances to 11.5 pm at the design current of 200 mA, assuming round beams. The Touschek lifetime is quite large in PEP-X, 11.6 hours, and - near the operating point - increases with decreasing emittance. It is, however, a very sensitive function of momentum acceptance. In an ultimate ring like PEP-X impedance driven collective effects tend not to be important since the beam current is relatively low. Before ultimate PEP-X can be realized, the question of how to run a machine with round beams needs serious study. For example, in this report we assumed that the vertical emittance is coupling dominated. It may turn out that using vertical dispersion is a preferable way to generate round beams. The choice will affect IBS and the Touschek effect.« less

Burton Richter, Storage Rings, and the J/psi Particle

Science.gov Websites

[SLAC's] Technical Director, [Richter] became Director ... from 1984 through 1999. During his tenure, SLAC Limits of Quantum Electro-dynamics, DOE Technical Report, June 1959 Design Considerations for High Energy Electron -- Positron Storage Rings, DOE Technical Report, November 1966 Inclusive Yields of pi+, pi-, K

Tree- Rings Link Climate and Carbon Storage in a Northern Mixed Hardwood Forest

NASA Astrophysics Data System (ADS)

Chiriboga, A.

2007-12-01

The terrestrial biosphere is a variable sink for atmospheric carbon dioxide. It is important to understand how carbon storage in trees is affected by natural climate variability to better characterize the sink. Quantifying the sensitivity of forest carbon storage to climate will improve carbon budgets and have implications for forest management practices. Here we explore how climate variability affects the ability of a northern mixed hardwood forest in Michigan to sequester atmospheric carbon dioxide in woody tissues. This site is ideal for studies of carbon sequestration; The University of Michigan Biological Station is an Ameriflux site, and has detailed meteorological and biometric records, as well as CO2 flux data. We have produced an 82- year aspen (Populus grandidentata) tree-ring chronology for this site, and measured ring widths at several heights up the bole. These measurements were used to estimate annual wood volume, which represents carbon allocated to aboveground carbon stores. Standard dendroclimatological techniques are used to identify environmental factors (e.g. temperature or precipitation) that drive tree-ring increment variability in the past century, and therefore annual carbon storage in this forest. Preliminary results show that marker years within the tree- ring chronology correspond with years that have cold spring temperatures. This suggests that trees at this site are temperature sensitive.

FLSR - The Frankfurt low energy storage ring

NASA Astrophysics Data System (ADS)

Stiebing, K. E.; Alexandrov, V.; Dörner, R.; Enz, S.; Kazarinov, N. Yu.; Kruppi, T.; Schempp, A.; Schmidt Böcking, H.; Völp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

2010-02-01

An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut für Kernphysik der Johann Wolfgang Goethe-Universität Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

Symplectic orbit and spin tracking code for all-electric storage rings

DOE PAGES

Talman, Richard M.; Talman, John D.

2015-07-22

Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring “trap.” At the “magic” kinetic energy of 232.792 MeV, proton spins are “frozen,” for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10 –29e–cm or greater will produce a statisticallymore » significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial “symplectification”). Any residual spurious damping or antidamping is sufficiently small to permit

The MAX IV storage ring project

PubMed Central

Tavares, Pedro F.; Leemann, Simon C.; Sjöström, Magnus; Andersson, Åke

2014-01-01

The MAX IV facility, currently under construction in Lund, Sweden, features two electron storage rings operated at 3 GeV and 1.5 GeV and optimized for the hard X-ray and soft X-ray/VUV spectral ranges, respectively. A 3 GeV linear accelerator serves as a full-energy injector into both rings as well as a driver for a short-pulse facility, in which undulators produce X-ray pulses as short as 100 fs. The 3 GeV ring employs a multibend achromat (MBA) lattice to achieve, in a relatively short circumference of 528 m, a bare lattice emittance of 0.33 nm rad, which reduces to 0.2 nm rad as insertion devices are added. The engineering implementation of the MBA lattice raises several technological problems. The large number of strong magnets per achromat calls for a compact design featuring small-gap combined-function magnets grouped into cells and sharing a common iron yoke. The small apertures lead to a low-conductance vacuum chamber design that relies on the chamber itself as a distributed copper absorber for the heat deposited by synchrotron radiation, while non-evaporable getter (NEG) coating provides for reduced photodesorption yields and distributed pumping. Finally, a low main frequency (100 MHz) is chosen for the RF system yielding long bunches, which are further elongated by passively operated third-harmonic Landau cavities, thus alleviating collective effects, both coherent (e.g. resistive wall instabilities) and incoherent (intrabeam scattering). In this paper, we focus on the MAX IV 3 GeV ring and present the lattice design as well as the engineering solutions to the challenges inherent to such a design. As the first realisation of a light source based on the MBA concept, the MAX IV 3 GeV ring offers an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources. PMID:25177978

Fundamentals of Coherent Synchrotron Radiation in Storage Rings

NASA Astrophysics Data System (ADS)

Sannibale, F.; Byrd, J. M.; Loftsdottir, A.; Martin, M. C.; Venturini, M.

2004-05-01

We present the fundamental concepts for producing stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The analysis includes distortion of bunch shape from the synchrotron radiation (SR), enhancing higher frequency coherent emission and limits to stable emission due to a microbunching instability excited by the SR. We use these concepts to optimize the performance of a source for CSR emission.

Picosecond, tunable, high-brightness hard x-ray inverse Compton source at Duke storage ring

NASA Astrophysics Data System (ADS)

Litvinenko, Vladimir N.; Wu, Ying; Burnham, Bentley; Barnett, Genevieve A.; Madey, John M. J.

1995-09-01

We suggest a state-of-the art x-ray source using a compact electron storage ring with modest energy (less than 1 GeV) and a high power mm-wave as an undulator. A source of this type has x-ray energies and brightness comparable with third generation synchrotron light sources while it can be very compact and fit in a small university or industrial laboratory or hospital. We propose to operate an isochronous mm-wave FEL and a hard x-ray inverse Compton source at the Duke storage ring to test this concept. Resonant FEL conditions for the mm- wave will be provided by the off-axis interaction with an electromagnetic wave. A special optical resonator with holes for the e-beam is proposed for pumping a hard x-ray inverse Compton source with very high brightness. Simulation results of mm-wave FEL operation of the Duke storage ring are discussed. Expected performance of mm-wave FEL and hard x-ray inverse Compton source are presented.

NSLS-II storage ring insertion device and front-end commissioning and operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, G., E-mail: gwang@bnl.gov; Shaftan, T.; Amundsen, C.

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. During spring/ summer of 2014, the storage ring was commissioned up to 50 mA without insertion devices. In the fall of 2014, we began commissioning of the project beamlines, which included seven insertion devices on six ID ports. Beamlines IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1 consist of elliptically polarized undulator (EPU), damping wigglers (DW) and in-vacuum undulators (IVU) covering from VUV to hard x-ray range. In this paper, experience with commissioning and operation is discussed.more » We focus on reaching storage ring performance with IDs, including injection, design emittance, compensation of orbit distortions caused by ID residual field, source point stability, beam alignment and tools for control, monitoring and protection of the ring chambers from ID radiation.« less

Dielectronic recombination experiments at the storage rings: From the present CSR to the future HIAF

NASA Astrophysics Data System (ADS)

Huang, Z. K.; Wen, W. Q.; Xu, X.; Wang, H. B.; Dou, L. J.; Chuai, X. Y.; Zhu, X. L.; Zhao, D. M.; Li, J.; Ma, X. M.; Mao, L. J.; Yang, J. C.; Yuan, Y. J.; Xu, W. Q.; Xie, L. Y.; Xu, T. H.; Yao, K.; Dong, C. Z.; Zhu, L. F.; Ma, X.

2017-10-01

Dielectronic recombination (DR) experiments of highly charged ions at the storage rings have been developed as a precision spectroscopic tool to investigate the atomic structure as well as nuclear properties of stable and unstable nuclei. The DR experiment on lithium-like argon ions was successfully performed at main Cooler Storage Ring (CSRm) at Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex. The DR experiments on heavy highly charged ions and even radioactive ions are currently under preparation at the experimental Cooler Storage Ring (CSRe) at HIRFL. The current status of DR experiments at the CSRm and the preparation of the DR experiments at the CSRe are presented. In addition, an overview of DR experiments by employing an electron cooler and a separated ultra-cold electron target at the upcoming High Intensity heavy ion Accelerator Facility (HIAF) will be given.

ACCELERATORS: Preliminary application of turn-by-turn data analysis to the SSRF storage ring

NASA Astrophysics Data System (ADS)

Chen, Jian-Hui; Zhao, Zhen-Tang

2009-07-01

There is growing interest in utilizing the beam position monitor turn-by-turn (TBT) data to debug accelerators. TBT data can be used to determine the linear optics, coupled optics and nonlinear behaviors of the storage ring lattice. This is not only a useful complement to other methods of determining the linear optics such as LOCO, but also provides a possibility to uncover more hidden phenomena. In this paper, a preliminary application of a β function measurement to the SSRF storage ring is presented.

Analysis of Methods to Excite Head-Tail Motion Within the Cornell Electron Storage Ring

NASA Astrophysics Data System (ADS)

Gendler, Naomi; Billing, Mike; Shanks, Jim

The main accelerator complex at Cornell consists of two rings around which electrons and positrons move: the synchrotron, where the particles are accelerated to 5 GeV, and the Storage Ring, where the particles circulate a ta Þxed energy, guided by quadrupole and dipole magnets, with a steady energy due to a sinusoidal voltage source. Keeping the beam stable in the Storage Ring is crucial for its lifetime. A long-lasting, invariable beam means more accurate experiments, as well as brighter, more focused X-rays for use in the Cornell High Energy Synchrotron Source (CHESS). The stability of the electron and positron beams in the Cornell Electron Storage Ring (CESR) is important for the development of accelerators and for usage of the beam in X-ray science and accelerator physics. Bunch oscillations tend to enlarge the beam's cross section, making it less stable. We believe that one such oscillation is ``head-tail motion,'' where the bunch rocks back and forth on a pivot located at the central particle. In this project, we write a simulation of the bunch that induces head-tail motion with a vertical driver. We also excite this motion physically in the storage ring, and observe a deÞnite head-tail signal. In the experiment, we saw a deÞnite persistence of the drive-damp signal within a small band around the head-tail frequency, indicating that the head-tail frequency is a natural vertical mode of the bunch that was being excited. The signal seen in the experiment matched the signal seen in the simulation to within an order of magnitude.

Preparing the MAX IV storage rings for timing-based experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stråhlman, C., E-mail: Christian.Strahlman@maxlab.lu.se; Olsson, T., E-mail: Teresia.Olsson@maxlab.lu.se; Leemann, S. C.

2016-07-27

Time-resolved experimental techniques are increasingly abundant at storage ring facilities. Recent developments in accelerator technology and beamline instrumentation allow for simultaneous operation of high-intensity and timing-based experiments. The MAX IV facility is a state-of-the-art synchrotron light source in Lund, Sweden, that will come into operation in 2016. As many storage ring facilities are pursuing upgrade programs employing strong-focusing multibend achromats and passive harmonic cavities (HCs) in high-current operation, it is of broad interest to study the accelerator and instrumentation developments required to enable timing-based experiments at such machines. In particular, the use of hybrid filling modes combined with pulse pickingmore » by resonant excitation or pseudo single bunch has shown promising results. These methods can be combined with novel beamline instrumentation, such as choppers and instrument gating. In this paper we discuss how these techniques can be implemented and employed at MAX IV.« less

Multi-objective dynamic aperture optimization for storage rings

DOE PAGES

Li, Yongjun; Yang, Lingyun

2016-11-30

We report an efficient dynamic aperture (DA) optimization approach using multiobjective genetic algorithm (MOGA), which is driven by nonlinear driving terms computation. It was found that having small low order driving terms is a necessary but insufficient condition of having a decent DA. Then direct DA tracking simulation is implemented among the last generation candidates to select the best solutions. The approach was demonstrated successfully in optimizing NSLS-II storage ring DA.

An analog RF gap voltage regulation system for the Advanced Photon Source storage ring.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horan, D.

1999-04-13

An analog rf gap voltage regulation system has been designed and built at Argonne National Laboratory to maintain constant total storage ring rf gap voltage, independent of beam loading and cavity tuning effects. The design uses feedback control of the klystron mod-anode voltage to vary the amount of rf power fed to the storage ring cavities. The system consists of two independent feedback loops, each regulating the combined rf gap voltages of eight storage ring cavities by varying the output power of either one or two rf stations, depending on the mode of operation. It provides full operator control andmore » permissive logic to permit feedback control of the rf system output power only if proper conditions are met. The feedback system uses envelope-detected cavity field probe outputs as the feedback signal. Two different methods of combining the individual field probe signals were used to generate a relative DC level representing one-half of the total storage ring rf voltage, an envelope-detected vector sum of the field probe rf signals, and the DC sum of individual field probe envelope detector outputs. The merits of both methods are discussed. The klystron high-voltage power supply (HVPS) units are fitted with an analog interface for external control of the mod-anode voltage level, using a four-quadrant analog multiplier to modulate the HVPS mod-anode voltage regulator set-point in response to feedback system commands.« less

Pseudo-single-bunch mode for a 100 MHz storage ring serving soft X-ray timing experiments

NASA Astrophysics Data System (ADS)

Olsson, T.; Leemann, S. C.; Georgiev, G.; Paraskaki, G.

2018-06-01

At many storage rings for synchrotron light production there is demand for serving both high-flux and timing users simultaneously. Today this is most commonly achieved by operating inhomogeneous fill patterns, but this is not preferable for rings that employ passive harmonic cavities to damp instabilities and increase Touschek lifetime. For these rings, inhomogeneous fill patterns could severely reduce the effect of the harmonic cavities. It is therefore of interest to develop methods to serve high-flux and timing users simultaneously without requiring gaps in the fill pattern. One such method is pseudo-single-bunch (PSB), where one bunch in the bunch train is kicked onto another orbit by a fast stripline kicker. The light emitted from the kicked bunch can then be separated by an aperture in the beamline. Due to recent developments in fast kicker design, PSB operation in multibunch mode is within reach for rings that operate with a 100 MHz RF system, such as the MAX IV and Solaris storage rings. This paper describes machine requirements and resulting performance for such a mode at the MAX IV 1.5 GeV storage ring. A solution for serving all beamlines is discussed as well as the consequences of beamline design and operation in the soft X-ray energy range.

Measurement of Systematic Error Effects for a Sensitive Storage Ring EDM Polarimeter

NASA Astrophysics Data System (ADS)

Imig, Astrid; Stephenson, Edward

2009-10-01

The Storage Ring EDM Collaboration was using the Cooler Synchrotron (COSY) and the EDDA detector at the Forschungszentrum J"ulich to explore systematic errors in very sensitive storage-ring polarization measurements. Polarized deuterons of 235 MeV were used. The analyzer target was a block of 17 mm thick carbon placed close to the beam so that white noise applied to upstream electrostatic plates increases the vertical phase space of the beam, allowing deuterons to strike the front face of the block. For a detector acceptance that covers laboratory angles larger than 9 ^o, the efficiency for particles to scatter into the polarimeter detectors was about 0.1% (all directions) and the vector analyzing power was about 0.2. Measurements were made of the sensitivity of the polarization measurement to beam position and angle. Both vector and tensor asymmetries were measured using beams with both vector and tensor polarization. Effects were seen that depend upon both the beam geometry and the data rate in the detectors.

Generalized Stability Conditions for an Ultra-Low Energy Electrostatic Charged Particle Storage Ring

NASA Astrophysics Data System (ADS)

Sullivan, Michael

A low energy (~50 eV) electrostatic storage ring has been constructed that can store a recirculating bunch of either electrons or ions. The charged particle bunch 'orbits' within an apparatus consisting of four lenses and two hemispherical deflector analysers, arranged in a 'race-track' configuration of length 64.1 cm. A theoretical study, using transfer matrices from charged particle optics for a 'symmetric' configuration of lens potentials, has been previously completed by Hammond et al. [New J. Phys. 11 (2009) 043033]. That approach was capable of predicting modes of storage which appeared as a resonant-like pattern. An 'asymmetric' configuration, new in this work and extending the previous study to apply to a more general case, has been completed and will be presented alongside experimental results. The level of agreement between the theoretical and experimental results is found to be excellent, and the robustness of the matrix formalism has eliminated the need to rely on computer simulation to achieve storage. This asymmetric arrangement of the lenses allows for greater flexibility in the operation of the ring, creating the potential for a more diverse range of applications and potentially aid in the design of future rings. Several spectra for both electrons and positive ions are presented to provide an indication as to how the charged particle bunch evolves as more orbits are completed. The number of counts inevitably decreases as a function of orbit number due to loss mechanisms. Enhanced measurement techniques, as well as the matrix theory, have made storage of the bunch for over a hundred orbits routine, corresponding to over 65 m travelled, and this is observed directly from the spectra. The application of the storage ring as a multi-pass time-of-flight mass spectrometer has been studied. The isotopes of krypton and xenon have been made to completely separate from one another out of a single pulse of ions. This is observed to occur after ~15 orbits of the

A multiple-orbit time-of-flight mass spectrometer based on a low energy electrostatic storage ring

NASA Astrophysics Data System (ADS)

Sullivan, M. R.; Spanjers, T. L.; Thorn, P. A.; Reddish, T. J.; Hammond, P.

2012-11-01

The results are presented for an electrostatic storage ring, consisting of two hemispherical deflector analyzers (HDA) connected by two separate sets of cylindrical lenses, used as a time-of-flight mass spectrometer. Based on the results of charged particle simulations and formal matrix model, the Ion Storage Ring is capable of operating with multiple stable orbits, for both single and multiply charged ions simultaneously.

PEGASYS---A proposed internal target facility for the PEP storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Biber, K.

A proposal for an integral gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable, luminosity (L = 10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/) and energy (E/sub e/ less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 14 refs., 7 figs.

First storage of ion beams in the Double Electrostatic Ion-Ring Experiment: DESIREE.

PubMed

Schmidt, H T; Thomas, R D; Gatchell, M; Rosén, S; Reinhed, P; Löfgren, P; Brännholm, L; Blom, M; Björkhage, M; Bäckström, E; Alexander, J D; Leontein, S; Hanstorp, D; Zettergren, H; Liljeby, L; Källberg, A; Simonsson, A; Hellberg, F; Mannervik, S; Larsson, M; Geppert, W D; Rensfelt, K G; Danared, H; Paál, A; Masuda, M; Halldén, P; Andler, G; Stockett, M H; Chen, T; Källersjö, G; Weimer, J; Hansen, K; Hartman, H; Cederquist, H

2013-05-01

We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C(n)(-), n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C2 (-) molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s ± 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10(-14) mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.

Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

NASA Astrophysics Data System (ADS)

Husain, Riyasat; Ghodke, A. D.

2017-08-01

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

Model-independent and fast determination of optical functions in storage rings via multiturn and closed-orbit data

NASA Astrophysics Data System (ADS)

Riemann, Bernard; Grete, Patrick; Weis, Thomas

2011-06-01

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

Phase measurement for driven spin oscillations in a storage ring

NASA Astrophysics Data System (ADS)

Hempelmann, N.; Hejny, V.; Pretz, J.; Soltner, H.; Augustyniak, W.; Bagdasarian, Z.; Bai, M.; Barion, L.; Berz, M.; Chekmenev, S.; Ciullo, G.; Dymov, S.; Eversmann, D.; Gaisser, M.; Gebel, R.; Grigoryev, K.; Grzonka, D.; Guidoboni, G.; Heberling, D.; Hetzel, J.; Hinder, F.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Koop, I.; Kulikov, A.; Lehrach, A.; Lenisa, P.; Lomidze, N.; Lorentz, B.; Maanen, P.; Macharashvili, G.; Magiera, A.; Mchedlishvili, D.; Mey, S.; Müller, F.; Nass, A.; Nikolaev, N. N.; Nioradze, M.; Pesce, A.; Prasuhn, D.; Rathmann, F.; Rosenthal, M.; Saleev, A.; Schmidt, V.; Semertzidis, Y.; Senichev, Y.; Shmakova, V.; Silenko, A.; Slim, J.; Stahl, A.; Stassen, R.; Stephenson, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Tagliente, G.; Talman, R.; Thörngren Engblom, P.; Trinkel, F.; Uzikov, Yu.; Valdau, Yu.; Valetov, E.; Vassiliev, A.; Weidemann, C.; Wrońska, A.; Wüstner, P.; Zuprański, P.; Żurek, M.; JEDI Collaboration

2018-04-01

This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in Jülich using a vector polarized, bunched 0.97 GeV /c deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.

Magnetic Measurements of Storage Ring Magnets for the APS Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doose, C.; Dejus, R.; Jaski, M.

2017-06-01

Extensive prototyping of storage ring magnets is ongoing at the Advanced Photon Source (APS) in support of the APS Multi-Bend Achromat (MBA) upgrade project (APS-U) [1]. As part of the R&D activities four quadrupole magnets with slightly different geometries and pole tip materials, and one sextupole magnet with vanadium permendur (VP) pole tips were designed, built and tested. Magnets were measured individually using a rotating coil and a Hall probe for detailed mapping of the magnetic field. Magnets were then assembled and aligned relative to each other on a steel support plate and concrete plinth using precision machined surfaces tomore » gain experience with the alignment method chosen for the APS-U storage ring magnets. The required alignment of magnets on a common support structure is 30 μm rms. Measurements of magnetic field quality, strength and magnet alignment after subjecting the magnets and assemblies to different tests are presented.« less

Modeling Systematic Error Effects for a Sensitive Storage Ring EDM Polarimeter

NASA Astrophysics Data System (ADS)

Stephenson, Edward; Imig, Astrid

2009-10-01

The Storage Ring EDM Collaboration has obtained a set of measurements detailing the sensitivity of a storage ring polarimeter for deuterons to small geometrical and rate changes. Various schemes, such as the calculation of the cross ratio [1], can cancel effects due to detector acceptance differences and luminosity differences for states of opposite polarization. Such schemes fail at second-order in the errors, becoming sensitive to geometrical changes, polarization magnitude differences between opposite polarization states, and changes to the detector response with changing data rates. An expansion of the polarimeter response in a Taylor series based on small errors about the polarimeter operating point can parametrize such effects, primarily in terms of the logarithmic derivatives of the cross section and analyzing power. A comparison will be made to measurements obtained with the EDDA detector at COSY-J"ulich. [4pt] [1] G.G. Ohlsen and P.W. Keaton, Jr., NIM 109, 41 (1973).

Pushing the MAX IV 3 GeV storage ring brightness and coherence towards the limit of its magnetic lattice

NASA Astrophysics Data System (ADS)

Leemann, S. C.; Wurtz, W. A.

2018-03-01

The MAX IV 3 GeV storage ring is presently being commissioned and crucial parameters such as machine functions, emittance, and stored current have either already been reached or are approaching their design specifications. Once the baseline performance has been achieved, a campaign will be launched to further improve the brightness and coherence of this storage ring for typical X-ray users. During recent years, several such improvements have been designed. Common to these approaches is that they attempt to improve the storage ring performance using existing hardware provided for the baseline design. Such improvements therefore present more short-term upgrades. In this paper, however, we investigate medium-term improvements assuming power supplies can be exchanged in an attempt to push the brightness and coherence of the storage ring to the limit of what can be achieved without exchanging the magnetic lattice itself. We outline optics requirements, the optics optimization process, and summarize achievable parameters and expected performance.

Status of NSLS-II Storage Ring Vacuum Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doom,L.; Hseuh,H.; Ferreira, M.

2009-05-04

National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3-GeV, high-flux and high- brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system will have extruded aluminium chambers with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers will be used to intercept the un-used bending magnet radiation. In-situ bakeout will be implemented to achieve fast conditioning during initial commissioning and after interventions.

Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.

PubMed

Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

2017-10-06

Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.

BEAM DIAGNOSTICS USING BPM SIGNALS FROM INJECTED AND STORED BEAMS IN A STORAGE RING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, G.M.; Shaftan; T.

2011-03-28

Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. The storage ring always has the stored beam and injected beam for top-off injection mode. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use dedicated wide band BPM electronics in the NSLS II storage ring to retrieve the injected beam trajectory with the singular value decomposition (SVD) method. The beam position monitor (BPM) has the capability to measure bunch-by-bunch beam position. Similar electronics can be used tomore » measure the bunch-by-bunch beam current which is necessary to get the injection beam position. The measurement precision of current needs to be evaluated since button BPM sum signal has position dependence. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.« less

Magnet design for a low-emittance storage ring

PubMed Central

Johansson, Martin; Anderberg, Bengt; Lindgren, Lars-Johan

2014-01-01

The MAX IV 3 GeV storage ring, currently under construction, pursues the goal of low electron beam emittance by using a multi-bend achromat magnet lattice, which is realised by having several consecutive magnet elements precision-machined out of a common solid iron block, 2.3–3.4 m long. With this magnet design solution, instead of having 1320 individual magnets, the MAX IV 3 GeV storage ring is built up using 140 integrated ‘magnet block’ units, containing all these magnet elements. Major features of this magnet block design are compactness, vibration stability and that the alignment of magnet elements within each unit is given by the mechanical accuracy of the CNC machining rather than individual field measurement and adjustment. This article presents practical engineering details of implementing this magnet design solution, and mechanical + magnetic field measurement results from the magnet production series. At the time of writing (spring 2014), the production series, which is totally outsourced to industry, is roughly half way through, with mechanical/magnetic QA conforming to specifications. It is the conclusion of the authors that the MAX IV magnet block concept, which has sometimes been described as new or innovative, is from a manufacturing point of view simply a collection of known mature production methods and measurement procedures, which can be executed at fixed cost with a low level of risk. PMID:25177980

Extreme Drought Events Revealed in Amazon Tree Ring Records

NASA Astrophysics Data System (ADS)

Jenkins, H. S.; Baker, P. A.; Guilderson, T. P.

2010-12-01

The Amazon basin is a center of deep atmospheric convection and thus acts as a major engine for global hydrologic circulation. Yet despite its significance, a full understanding of Amazon rainfall variability remains elusive due to a poor historical record of climate. Temperate tree rings have been used extensively to reconstruct climate over the last thousand years, however less attention has been given to the application of dendrochronology in tropical regions, in large part due to a lower frequency of tree species known to produce annual rings. Here we present a tree ring record of drought extremes from the Madre de Dios region of southeastern Peru over the last 190 years. We confirm that tree ring growth in species Cedrela odorata is annual and show it to be well correlated with wet season precipitation. This correlation is used to identify extreme dry (and wet) events that have occurred in the past. We focus on drought events identified in the record as drought frequency is expected to increase over the Amazon in a warming climate. The Cedrela chronology records historic Amazon droughts of the 20th century previously identified in the literature and extends the record of drought for this region to the year 1816. Our analysis shows that there has been an increase in the frequency of extreme drought (mean recurrence interval = 5-6 years) since the turn of the 20th century and both Atlantic and Pacific sea surface temperature (SST) forcing mechanisms are implicated.

Preliminary study of injection transients in the TPS storage ring

NASA Astrophysics Data System (ADS)

Chen, C. H.; Liu, Y. C.; Y Chen, J.; Chiu, M. S.; Tseng, F. H.; Fann, S.; Liang, C. C.; Huang, C. S.; Y Lee, T.; Y Chen, B.; Tsai, H. J.; Luo, G. H.; Kuo, C. C.

2017-07-01

An optimized injection efficiency is related to a perfect match between the pulsed magnetic fields in the storage ring and transfer line extraction in the TPS. However, misalignment errors, hardware output errors and leakage fields are unavoidable. We study the influence of injection transients on the stored TPS beam and discuss solutions to compensate these. Related simulations and measurements will be presented.

Stochastic events lead to accretion in Saturn's rings

NASA Astrophysics Data System (ADS)

Esposito, Larry W.

2010-05-01

UVIS occultations indicate accretion is triggered at the B ring edge, in strong density waves in ring A and in the F ring. Moons may trigger accretion by streamline crowding (Lewis & Stewart); which enhances collisions, leading to accretion; increasing random velocities; leading to more collisions and more accretion. Cassini occultations of these strongly perturbed locations show not only accretion but also disaggregation, with time scales of hours to weeks. The collisions may lead to temporary aggregations via stochastic events: collisions can compress unconsolidated objects, trigger adhesion or bring small pieces into contact with larger or higher-density seeds. Disaggregation then can follow from disruptive collisions or tidal shedding. In the accretion/disruption balance, increased random motions could eventually give the upper hand to disruption… just as ‘irrational exuberance' can lead to financial panic in the economy; or the overpopulation of hares can lead to boom-and-bust in the population of foxes. This unstable equilibrium can similarly give rise to episodic cycles in accretion: explaining why the observable ring features that indicate embedded objects have been increasing since the beginning of Cassini's observations of Saturn in 2004.

Spin Filtering in Storage Rings

NASA Astrophysics Data System (ADS)

Nikolaev, N. N.; Pavlov, F. F.

The spin filtering in storage rings is based on a multiple passage of a stored beam through a polarized internal gas target. Apart from the polarization by the spin-dependent transmission, a unique geometrical feature of interaction with the target in such a filtering process, pointed out by H.O. Meyer,1 is a scattering of stored particles within the beam. A rotation of the spin in the scattering process affects the polarization buildup. We derive here a quantum-mechanical evolution equation for the spin-density matrix of a stored beam which incorporates the scattering within the beam. We show how the interplay of the transmission and scattering within the beam changes from polarized electrons to polarized protons in the atomic target. After discussions of the FILTEX results on the filtering of stored protons,2 we comment on the strategy of spin filtering of antiprotons for the PAX experiment at GSI FAIR.3.

Astrochemistry at the Cryogenic Storage Ring

NASA Astrophysics Data System (ADS)

Kreckel, Holger; Becker, Arno; Blaum, Klaus; Breitenfeldt, Christian; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth; Heber, Oded; Karthein, Jonas; Krantz, Claude; Meyer, Christian; Mishra, Preeti; Novotny, Oldrich; O'Connor, Aodh; Saurabh, Sunny; Schippers, Stefan; Spruck, Kaija; Kumar, S. Sunil; Urbain, Xavier; Vogel, Stephen; von Hahn, Robert; Wilhelm, Patrick; Wolf, Andreas; Zajfman, Daniel

2017-01-01

Almost 200 different molecular species have been identified in space, and this number continues to grow steadily. This surprising molecular diversity bears witness to an active reaction network, in which molecular ions are the main drivers of chemistry in the gas phase. To study these reactions under controlled conditions in the laboratory is a major experimental challenge. The new Cryogenic Storage Ring (CSR) that has recently been commissioned at the Max Planck Institute for Nuclear Physics in Heidelberg will serve as an ideal testbed to study cold molecular ions in the gas phase. With residual gas densities of <140 cm-3 and temperatures below 10K, the CSR will allow for merged beams collision studies involving molecular ions, neutral atoms, free electrons and photons under true interstellar conditions.

Upgrade of BPM Electronics for the SPring-8 Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasaki, Shigeki; Fujita, Takahiro; Shoji, Masazumi

2006-11-20

SPring-8, a 3rd generation synchrotron light source, has operated since 1997. Improvement of BPM performance is required as a part of upgrading activities of the storage ring as a light source. We have developed new electronics circuits for signal processing of the storage ring BPM, with target performance of sub-{mu}m range resolution with sufficiently fast measurement speed and good long-term stability. A set of the new circuits consists of multiplexers, an RF amplifier, a mixer, an IF amplifier, and a local oscillator for analog signal processing. The IF amplifier outputs are sampled with 16-bit 2-MSPS ADC on ADC boards andmore » the data are sent to a DSP board. The sampled data are processed and converted to position information in the DSP. A multiplexing method was employed to have a better stability of the performance by cancellation of variation common to each channel. Evaluation of the performance by using a prototype shows that position resolution well into the sub-{mu}m range has been achieved with a bandwidth of 1 kHz, and long-term stability of within 1 {mu}m has also been achieved.« less

Search for the 1P 1 charmonium state in overlinepp annihilations at the CERN intersecting storage rings

NASA Astrophysics Data System (ADS)

Baglin, C.; Baird, S.; Bassompierre, G.; Borreani, G.; Brient, J.-C.; Broll, C.; Brom, J.-M.; Bugge, L.; Buran, T.; Burq, J.-P.; Bussière, A.; Buzzo, A.; Cester, R.; Chemarin, M.; Chevallier, M.; Escoubes, B.; Fay, J.; Ferroni, S.; Gracco, V.; Guillaud, J.-P.; Khan-Aronsen, E.; Kirsebom, K.; Kylling, A.; Ille, B.; Lambert, M.; Leistam, L.; Lundby, A.; Macri, M.; Marchetto, F.; Menichetti, E.; Mörch, Ch.; Mouellic, B.; Olsen, D.; Pastrone, N.; Petrillo, L.; Pia, M. G.; Poole, J.; Poulet, M.; Rinaudo, G.; Santroni, A.; Severi, M.; Skjevling, G.; Stapnes, S.; Stugu, B.; R704 Collaboration

1986-04-01

This experiment has been performed at the CERN Intersecting Storage Rings to study the direct formation of charmonium states in antiproton-proton annihilations. The experimental program has partly been devoted to an inclusive scan for overlinepp → J/ψ + X in the range 3520-3530 MeV/ c2. A cluster of five events has been observed in a narrow energy band, centred on the centre of gravity of the 3P J states where the 1P 1 is expected to be. When interpreted as a new resonace, these data yield a mass m = 3525.4±0.8 MeV/ c2.

Storage Rings in the Sky: Gamma Ray Bursts and Galactic Gravitational Collapse Stored Energy

NASA Astrophysics Data System (ADS)

Greyber, H. D.

2004-05-01

The recent discovery of almost 100% polarization of the prompt gamma ray emission from GRB021206, (1), confirms my 44 year old ``Strong" Magnetic Field" model (SMF) for galactic dynamics. In SMF, Storage Ring particles were accelerated long ago during the original gravitational collapse of the pregalactic/prequasar plasma cloud that is permeated by an almost uniform primordial magnetic field (2,3) The enormous, intense, slender, relativistic, stable, completely coherent Storage Ring stores a very small fraction of the huge galactic gravitational collapse energy in an almost radiationless state, unless disturbed. The concept of an Astrophysical Storage Ring was introduced by me in l961. At first it was to explain galactic structure, but soon it proved useful to explain active galactic nuclei (AGN) and the dynamics of quasar/AGN jets. AGN and galactic morphology, energetics and dynamics vary as the ratio of magnetic energy to rotational energy in the particular object. Gamma ray bursts (GRB) are due simply to a ``rock". i.e. a white dwarf, ordinary star, neutron sstar, asteroid, planet, etc. falling rapidly through the Storage Ring and being almost instantly vaporized into a hot plasma fireball, causing an electromagnetic shower (2) Then the fireball speeds into the huge organized magnetic field surrounding the current ring, thus generating very highly polarized prompt gamma ray emission (as seen in GRB021206) from the synchrotron radiation process. The timing fits the GRB observations nicely. For instance, a ``rock" racing at 1000 kilometers per second across a 20,000 km. path in the beam would produce a twenty second burst. Other times, a target might track across a short chord for a short burst. Space missions have shown that often typical currents in space plasmas are made up of slender filaments. Thus the puzzling less than one millisecond spikes observed in some GRB are simply describing the structure of that particular ring current at that particular time. 1

Low emittance lattice for the storage ring of the Turkish Light Source Facility TURKAY

NASA Astrophysics Data System (ADS)

Nergiz, Z.; Aksoy, A.

2015-06-01

The TAC (Turkish Accelerator Center) project aims to build an accelerator center in Turkey. The first stage of the project is to construct an Infra-Red Free Electron Laser (IR-FEL) facility. The second stage is to build a synchrotron radiation facility named TURKAY, which is a third generation synchrotron radiation light source that aims to achieve a high brilliance photon beam from a low emittance electron beam at 3 GeV. The electron beam parameters are highly dependent on the magnetic lattice of the storage ring. In this paper a low emittance storage ring for TURKAY is proposed and the beam dynamic properties of the magnetic lattice are investigated. Supported by Turkish Republic Ministry of Development (DPT2006K120470)

PEGASYS: A proposed internal target-spectrometer facility for the PEP storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Bibber, K.

A proposal for an internal gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable luminosity (L=10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/ decreasing as Z/sup /minus/1.75/ for nuclear targets) and energy (E/sub e/less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 17 refs., 5 figs.

Design study of the storage ring EUTERPE

NASA Astrophysics Data System (ADS)

Xi, Boling; Botman, J. I. M.; Timmermans, C. J.; Hagedoorn, H. L.

1992-05-01

At present the 400 MeV electron storage ring EUTERPE is being constructed at the Eindhoven University of Technology. It is a university project set up for studies of charged particle beam dynamics and applications of synchroton radiation, and for the education of students in these fields. The design of the ring is described in this paper. Considering the requirements of users in different fields, a lattice based on a so-called triple bend achromat structure with a high flexibility has been chosen. With this lattice, different optical options, including the HBSB (high brightness, small beam), the SBL (short bunch length) and the HLF (high light flux) modes can be realized. A small emittance of 7 nm rad and a short bunch length of the order of several mm can be achieved. In the first phase the synchrotron radiation in the UV and XUV region (the critical wavelength is 8.3 nm) will be provided from the regular dipole magnets. Later on, a 10 T wiggler magnet and other special inserters will be added, and other applications and beam dynamics studies will be feasible. Bending magnets are of the parallel faced C configuration. The effective aperture of the vacuum chamber is 2.3 cm (vertical) in the bending magnets and 4.7 cm elsewhere with a working vacuum condition of 10-9 Torr. Collective effects have been studied initially. First calculations indicate that a lifetime of several hours, influenced by the Touschek effect and residual gas scattering will be achievable for a 200 mA beam in the HLF mode for the standard rf parameters. A 70 MeV racetrack microtron will serve as injector for the ring.

Towards a 4{sup th} generation storage ring at the Canadian Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dallin, Les; Wurtz, Ward

2016-07-27

Demands from beamline scientists for more brilliant sources of synchrotron radiation have resulted in the emergence of 4{sup th} generation (diffraction-limited) storage rings. The practical development of the multi-bend achromat (MBA) concept by MAX IV lab has spurred many synchrotron light sources around the world to develop similar machines. For existing facilities two options are available: upgrading existing machines or building a new structure. The Canadian Light Source (CLS) has explored both options. For a new low emittance source in the existing CLS tunnel a decrease in electron energy would be required. A machine similar to the ALS upgrade couldmore » be contemplated. To achieve low emittance at our present energy of 2.9 GeV a new storage ring is desirable. Several options have been investigated. These designs use extremely strong focusing magnets to achieve extremely low emittances in compact lattice achromats.« less

Stochastic events lead to accretion in Saturn’s rings

NASA Astrophysics Data System (ADS)

Esposito, L. W.

2009-12-01

UVIS occultations indicate accretion is triggered at the B ring edge, in strong density waves in ring A and in the F ring. Moons may trigger accretion by streamline crowding (Lewis & Stewart); which enhances collisions, leading to accretion; increasing random velocities; leading to more collisions and more accretion. Cassini occultations of these strongly perturbed locations show not only accretion but also disaggregation, with time scales of hours to weeks. The collisions may lead to temporary aggregations via stochastic events: they can compress unconsolidated objects, trigger adhesion or bring small pieces into contact with larger or higher-density seeds. Disaggregation then can follow from disruptive collisions or tidal shedding. In the accretion/disruption balance, increased random motions could eventually give the upper hand to disruption… just as ‘irrational exuberance’ can lead to financial panic in the economy; or the overpopulation of hares can lead to boom-and-bust in the population of foxes. This unstable equilibrium can similarly give rise to episodic cycles in accretion: explaining why the observable ring features that indicate embedded objects have been increasing since the beginning of Cassini’s observations of Saturn in 2004.

Beam measurements using visible synchrotron light at NSLS2 storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Weixing, E-mail: chengwx@bnl.gov; Bacha, Bel; Singh, Om

2016-07-27

Visible Synchrotron Light Monitor (SLM) diagnostic beamline has been designed and constructed at NSLS2 storage ring, to characterize the electron beam profile at various machine conditions. Due to the excellent alignment, SLM beamline was able to see the first visible light when beam was circulating the ring for the first turn. The beamline has been commissioned for the past year. Besides a normal CCD camera to monitor the beam profile, streak camera and gated camera are used to measure the longitudinal and transverse profile to understand the beam dynamics. Measurement results from these cameras will be presented in this paper.more » A time correlated single photon counting system (TCSPC) has also been setup to measure the single bunch purity.« less

Ultrashort high-brightness pulses from storage rings

NASA Astrophysics Data System (ADS)

Khan, Shaukat

2017-09-01

The brightness of short-wavelength radiation from accelerator-based sources can be increased by coherent emission in which the radiation intensity scales with the number of contributing electrons squared. This requires a microbunched longitudinal electron distribution, which is the case in free-electron lasers. The brightness of light sources based on electron storage rings was steadily improved, but could profit further from coherent emission. The modulation of the electron energy by a continuous-wave laser field may provide steady-state microbunching in the infrared regime. For shorter wavelengths, the energy modulation can be converted into a temporary density modulation by a dispersive chicane. One particular goal is coherent emission from a very short "slice" within an electron bunch in order to produce ultrashort radiation pulses with high brightness.

Saw-tooth instability in storage rings: simulations and dynamical model

NASA Astrophysics Data System (ADS)

Migliorati, M.; Palumbo, L.; Dattoli, G.; Mezi, L.

1999-11-01

The saw-tooth instability in storage rings is studied by means of a time-domain simulation code which takes into account the self-induced wake fields. The results are compared with those from a dynamical heuristic model exploiting two coupled non-linear differential equations, accounting for the time behavior of the instability growth rate and for the anomalous growth of the energy spread. This model is shown to reproduce the characteristic features of the instability in a fairly satisfactory way.

Properties of the electron cloud in a high-energy positron and electron storage ring

DOE PAGES

Harkay, K. C.; Rosenberg, R. A.

2003-03-20

Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in amore » positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Furthermore, such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.« less

Experimental Evidence for the Los Alamos Proton Storage Ring Beam Instability

NASA Astrophysics Data System (ADS)

Plum, M.; Fitzgerald, D. H.; Macek, R.; Sander, O.; Thiessen, H. A.; Wang, T. S.; Wilkinson, C.

1997-05-01

Although the exact instability mechanism at the Proton Storage Ring (PSR) has not yet been conclusively identified, the evidence gathered to date is consistent with an e-p instability. We have recently acquired new data which shows that clearing electrodes significantly affect the instability threshold. A set of comprehensive measurements is also planned for the first months of 1997. In this paper we will present our latest data.

Emittance measurements in low energy ion storage rings

NASA Astrophysics Data System (ADS)

Hunt, J. R.; Carli, C.; Resta-López, J.; Welsch, C. P.

2018-07-01

The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurement faces several challenges: non-zero dispersion, non-Gaussian beam distributions due to effects of the electron cooler and various systematic errors such as closed orbit offsets and inaccurate rms momentum spread estimation. In addition, diffusion processes, such as intra-beam scattering might lead to emittance overestimates. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA.

A storage ring experiment to detect a proton electric dipole moment

DOE PAGES

Anastassopoulos, V.; Andrianov, S.; Baartman, R.; ...

2016-11-29

We describe a new experiment to detect a permanent electric dipole moment of the proton with a sensitivity of 10 $-$29e cm by using polarized “magic” momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000 TeV.

A storage ring experiment to detect a proton electric dipole moment.

PubMed

Anastassopoulos, V; Andrianov, S; Baartman, R; Baessler, S; Bai, M; Benante, J; Berz, M; Blaskiewicz, M; Bowcock, T; Brown, K; Casey, B; Conte, M; Crnkovic, J D; D'Imperio, N; Fanourakis, G; Fedotov, A; Fierlinger, P; Fischer, W; Gaisser, M O; Giomataris, Y; Grosse-Perdekamp, M; Guidoboni, G; Hacıömeroğlu, S; Hoffstaetter, G; Huang, H; Incagli, M; Ivanov, A; Kawall, D; Kim, Y I; King, B; Koop, I A; Lazarus, D M; Lebedev, V; Lee, M J; Lee, S; Lee, Y H; Lehrach, A; Lenisa, P; Levi Sandri, P; Luccio, A U; Lyapin, A; MacKay, W; Maier, R; Makino, K; Malitsky, N; Marciano, W J; Meng, W; Meot, F; Metodiev, E M; Miceli, L; Moricciani, D; Morse, W M; Nagaitsev, S; Nayak, S K; Orlov, Y F; Ozben, C S; Park, S T; Pesce, A; Petrakou, E; Pile, P; Podobedov, B; Polychronakos, V; Pretz, J; Ptitsyn, V; Ramberg, E; Raparia, D; Rathmann, F; Rescia, S; Roser, T; Kamal Sayed, H; Semertzidis, Y K; Senichev, Y; Sidorin, A; Silenko, A; Simos, N; Stahl, A; Stephenson, E J; Ströher, H; Syphers, M J; Talman, J; Talman, R M; Tishchenko, V; Touramanis, C; Tsoupas, N; Venanzoni, G; Vetter, K; Vlassis, S; Won, E; Zavattini, G; Zelenski, A; Zioutas, K

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10 -29 e ⋅ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the standard model at the scale of 3000 TeV.

A storage ring experiment to detect a proton electric dipole moment

NASA Astrophysics Data System (ADS)

Anastassopoulos, V.; Andrianov, S.; Baartman, R.; Baessler, S.; Bai, M.; Benante, J.; Berz, M.; Blaskiewicz, M.; Bowcock, T.; Brown, K.; Casey, B.; Conte, M.; Crnkovic, J. D.; D'Imperio, N.; Fanourakis, G.; Fedotov, A.; Fierlinger, P.; Fischer, W.; Gaisser, M. O.; Giomataris, Y.; Grosse-Perdekamp, M.; Guidoboni, G.; Hacıömeroǧlu, S.; Hoffstaetter, G.; Huang, H.; Incagli, M.; Ivanov, A.; Kawall, D.; Kim, Y. I.; King, B.; Koop, I. A.; Lazarus, D. M.; Lebedev, V.; Lee, M. J.; Lee, S.; Lee, Y. H.; Lehrach, A.; Lenisa, P.; Levi Sandri, P.; Luccio, A. U.; Lyapin, A.; MacKay, W.; Maier, R.; Makino, K.; Malitsky, N.; Marciano, W. J.; Meng, W.; Meot, F.; Metodiev, E. M.; Miceli, L.; Moricciani, D.; Morse, W. M.; Nagaitsev, S.; Nayak, S. K.; Orlov, Y. F.; Ozben, C. S.; Park, S. T.; Pesce, A.; Petrakou, E.; Pile, P.; Podobedov, B.; Polychronakos, V.; Pretz, J.; Ptitsyn, V.; Ramberg, E.; Raparia, D.; Rathmann, F.; Rescia, S.; Roser, T.; Kamal Sayed, H.; Semertzidis, Y. K.; Senichev, Y.; Sidorin, A.; Silenko, A.; Simos, N.; Stahl, A.; Stephenson, E. J.; Ströher, H.; Syphers, M. J.; Talman, J.; Talman, R. M.; Tishchenko, V.; Touramanis, C.; Tsoupas, N.; Venanzoni, G.; Vetter, K.; Vlassis, S.; Won, E.; Zavattini, G.; Zelenski, A.; Zioutas, K.

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10-29 e ṡ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the standard model at the scale of 3000 TeV.

A storage ring experiment to detect a proton electric dipole moment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastassopoulos, V.; Andrianov, S.; Baartman, R.

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity ofmore » $$10^{-29}e\\cdot$$cm by using polarized "magic" momentum $0.7$~GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000~TeV.« less

Storage ring two-color free-electron laser

DOE PAGES

Yan, J.; Hao, H.; Li, J. Y.; ...

2016-07-05

We report a systematic experimental study of a storage ring two-color free-electron laser (FEL) operating simultaneously in the infrared (IR) and ultraviolet (UV) wavelength regions. The two-color FEL lasing has been realized using a pair of dual-band high-reflectivity FEL mirrors with two different undulator configurations. We have demonstrated independent wavelength tuning in a wide range for each lasing color, as well as harmonically locked wavelength tuning when the UV lasing occurs at the second harmonic of the IR lasing. Precise power control of two-color lasing with good power stability has also been achieved. In addition, the impact of the degradationmore » of FEL mirrors on the two-color FEL operation is reported. Moreover, we have investigated the temporal structures of the two-color FEL beams, showing simultaneous two-color micropulses with their intensity modulations displayed as FEL macropulses.« less

Electron cooling of a bunched ion beam in a storage ring

NASA Astrophysics Data System (ADS)

Zhao, He; Mao, Lijun; Yang, Jiancheng; Xia, Jiawen; Yang, Xiaodong; Li, Jie; Tang, Meitang; Shen, Guodong; Ma, Xiaoming; Wu, Bo; Wang, Geng; Ruan, Shuang; Wang, Kedong; Dong, Ziqiang

2018-02-01

A combination of electron cooling and rf system is an effective method to compress the beam bunch length in storage rings. A simulation code based on multiparticle tracking was developed to calculate the bunched ion beam cooling process, in which the electron cooling, intrabeam scattering (IBS), ion beam space-charge field, transverse and synchrotron motion are considered. Meanwhile, bunched ion beam cooling experiments have been carried out in the main cooling storage ring (CSRm) of the Heavy Ion Research Facility in Lanzhou, to investigate the minimum bunch length obtained by the cooling method, and study the dependence of the minimum bunch length on beam and machine parameters. The experiments show comparable results to those from simulation. Based on these simulations and experiments, we established an analytical model to describe the limitation of the bunch length of the cooled ion beam. It is observed that the IBS effect is dominant for low intensity beams, and the space-charge effect is much more important for high intensity beams. Moreover, the particles will not be bunched for much higher intensity beam. The experimental results in CSRm show a good agreement with the analytical model in the IBS dominated regime. The simulation work offers us comparable results to those from the analytical model both in IBS dominated and space-charge dominated regimes.

BPM Breakdown Potential in the PEP-II B-factory Storage Ring Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weathersby, Stephen; Novokhatski, Alexander; /SLAC

2010-02-10

High current B-Factory BPM designs incorporate a button type electrode which introduces a small gap between the button and the beam chamber. For achievable currents and bunch lengths, simulations indicate that electric potentials can be induced in this gap which are comparable to the breakdown voltage. This study characterizes beam induced voltages in the existing PEP-II storage ring collider BPM as a function of bunch length and beam current.

The Potential-Well Distortion Effect and Coherent Instabilities of Electron Bunches in Storage Rings

NASA Astrophysics Data System (ADS)

Korchuganov, V. N.; Smygacheva, A. S.; Fomin, E. A.

2018-05-01

The effect of electromagnetic interaction between electron bunches and the vacuum chamber of a storage ring on the longitudinal motion of bunches is studied. Specifically, the potential-well distortion effect and the so-called coherent instabilities of coupled bunches are considered. An approximate analytical solution for the frequencies of incoherent oscillations of bunches distributed arbitrarily within the ring is obtained for a distorted potential well. A new approach to determining frequencies of coherent oscillations and an approximate analytical relation for estimating the stability of a system of bunches as a function of their distribution in the accelerator orbit are presented.

Safe operating conditions for NSLS-II Storage Ring Frontends commissioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seletskiy, S.; Amundsen, C.; Ha, K.

2015-04-02

The NSLS-II Storage Ring Frontends are designed to safely accept the synchrotron radiation fan produced by respective insertion device when the electron beam orbit through the ID is locked inside the predefined Active Interlock Envelope. The Active Interlock is getting enabled at a particular beam current known as AI safe current limit. Below such current the beam orbit can be anywhere within the limits of the SR beam acceptance. During the FE commissioning the beam orbit is getting intentionally disturbed in the particular ID. In this paper we explore safe operating conditions for the Frontends commissioning.

How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97 - GeV / c Deuterons in a Storage Ring

DOE PAGES

Guidoboni, G.; Stephenson, E.; Andrianov, S.; ...

2016-07-28

Here, we observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10 -29 $e$ cm.

Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

NASA Astrophysics Data System (ADS)

Krantz, C.; Novotný, O.; Becker, A.; George, S.; Grieser, M.; Hahn, R. von; Meyer, C.; Schippers, S.; Spruck, K.; Vogel, S.; Wolf, A.

2017-04-01

We have used a single-particle detector system, based on secondary electron emission, for counting low-energetic (∼keV/u) massive products originating from atomic and molecular ion reactions in the electrostatic Cryogenic Storage Ring (CSR). The detector is movable within the cryogenic vacuum chamber of CSR, and was used to measure production rates of a variety of charged and neutral daughter particles. In operation at a temperature of ∼ 6 K , the detector is characterised by a high dynamic range, combining a low dark event rate with good high-rate particle counting capability. On-line measurement of the pulse height distributions proved to be an important monitor of the detector response at low temperature. Statistical pulse-height analysis allows to infer the particle detection efficiency of the detector, which has been found to be close to unity also in cryogenic operation at 6 K.

X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens

PubMed Central

de Jonge, Martin D.; Ryan, Christopher G.; Jacobsen, Chris J.

2014-01-01

X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer. PMID:25177992

An undulator based soft x-ray source for microscopy on the Duke electron storage ring

NASA Astrophysics Data System (ADS)

Johnson, Lewis Elgin

1998-09-01

This dissertation describes the design, development, and installation of an undulator-based soft x-ray source on the Duke Free Electron Laser laboratory electron storage ring. Insertion device and soft x-ray beamline physics and technology are all discussed in detail. The Duke/NIST undulator is a 3.64-m long hybrid design constructed by the Brobeck Division of Maxwell Laboratories. Originally built for an FEL project at the National Institute of Standards and Technology, the undulator was acquired by Duke in 1992 for use as a soft x-ray source for the FEL laboratory. Initial Hall probe measurements on the magnetic field distribution of the undulator revealed field errors of more than 0.80%. Initial phase errors for the device were more than 11 degrees. Through a series of in situ and off-line measurements and modifications we have re-tuned the magnet field structure of the device to produce strong spectral characteristics through the 5th harmonic. A low operating K has served to reduce the effects of magnetic field errors on the harmonic spectral content. Although rms field errors remained at 0.75%, we succeeded in reducing phase errors to less than 5 degrees. Using trajectory simulations from magnetic field data, we have computed the spectral output given the interaction of the Duke storage ring electron beam and the NIST undulator. Driven by a series of concerns and constraints over maximum utility, personnel safety and funding, we have also constructed a unique front end beamline for the undulator. The front end has been designed for maximum throughput of the 1st harmonic around 40A in its standard mode of operation. The front end has an alternative mode of operation which transmits the 3rd and 5th harmonics. This compact system also allows for the extraction of some of the bend magnet produced synchrotron and transition radiation from the storage ring. As with any well designed front end system, it also provides excellent protection to personnel and to the

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-08-01

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

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-08-01

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

APS Storage Ring Monopulse RF BPM Upgrade

NASA Astrophysics Data System (ADS)

Lill, R.; Pietryla, A.; Norum, E.; Lenkszus, F.

2004-11-01

The Advanced Photon Source (APS) is a third-generation synchrotron light source in its ninth year of operation. The storage ring monopulse radio frequency (rf) beam position monitor (BPM) was designed to measure single-turn and multi-turn beam positions for operations and machine physics studies. Many of the components used in the original design are obsolete and costly to replace. In this paper we present a proposal to upgrade the monopulse rf BPMs in which the existing system hardware is repartitioned and the aging data acquisition system is replaced. By replacing only the data acquisition system, we will demonstrate a cost-effective approach to improved beam stability, reliability, and enhanced postmortem capabilities. An eight-channel ADC/digitizer VXI board with sampling rate of up to 105 MHz (per channel) and 14-bit resolution coupled with a field-programmable gate array and embedded central processing will provide the flexibility to revitalize this system for another decade of operation. We will discuss the upgrade system specifications, design, and prototype test results.

Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dees, Craig

2016-07-01

A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

Can Steady Magnetospheric Convection Events Inject Plasma into the Ring Current?

NASA Astrophysics Data System (ADS)

Lemon, C.; Chen, M. W.; Guild, T. B.

2009-12-01

Steady Magnetospheric Convection (SMC) events are characterized by several-hour periods of enhanced convection that are devoid of substorm signatures. There has long been a debate about whether substorms are necessary to inject plasma into the ring current, or whether enhanced convection is sufficient. If ring current injections occur during SMC intervals, this would suggest that substorms are unnecessary. We use a combination of simulations and data observations to examine this topic. Our simulation model computes the energy-dependent plasma drift in a self-consistent electric and magnetic field, which allows us to accurately model the transport of plasma from the plasma sheet (where the plasma pressure is much larger than the magnetic pressure) into the inner magnetosphere (where plasma pressure is much less than the magnetic pressure). In regions where the two pressures are comparable (i.e. the inner plasma sheet), feedback between the plasma and magnetic field is critical for accurately modeling the physical evolution of the system. Our previous work has suggested that entropy losses in the plasma sheet (such as caused by substorms) may be necessary to inject a ring current. However, it is not yet clear whether other small-scale processes (e.g. bursty bulk flows) can provide sufficient entropy loss in the plasma sheet to allow for the penetration of plasma into the ring current. We combine our simulation results with data observations in order to better understand the physical processes required to inject a ring current.

Explicit symplectic orbit and spin tracking method for electric storage ring

DOE PAGES

Hwang, Kilean; Lee, S. Y.

2016-08-18

We develop a symplectic charged particle tracking method for phase space coordinates and polarization in all electric storage rings. Near the magic energy, the spin precession tune is proportional to the fractional momentum deviation δ m from the magic energy, and the amplitude of the radial and longitudinal spin precession is proportional to η/δ m, where η is the electric dipole moment for an initially vertically polarized beam. As a result, the method can be used to extract the electron electric dipole moment of a charged particle by employing narrow band frequency analysis of polarization around the magic energy.

Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

Treesearch

Klemen Novak; Martin de Luis; Miguel A. Saz; Luis A. Longares; Roberto Serrano-Notivoli; Josep Raventos; Katarina Cufar; Jozica Gricar; Alfredo Di Filippo; Gianluca Piovesan; Cyrille B.K. Rathgeber; Andreas Papadopoulos; Kevin T. Smith

2016-01-01

Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of...

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-05-13

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

Space-charge-sustained microbunch structure in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Danilov, V.; Holmes, J.; Macek, R.

2004-09-01

We present experimental data from the Los Alamos Proton Storage Ring (PSR) showing long-lived linac microbunch structure during beam storage with no rf bunching. Analysis of the experimental data and particle-in-cell simulations of the experiments indicate that space charge, coupled with energy spread effects, is responsible for the sustained microbunch structure. The simulated longitudinal phase space of the beam reveals a well-defined separatrix in the phase space between linac microbunches, with particles executing unbounded motion outside of the separatrix. We show that the longitudinal phase space of the beam was near steady state during the PSR experiments, such that the separatrix persisted for long periods of time. Our simulations indicate that the steady state is very sensitive to the experimental conditions. Finally, we solve the steady-state problem in an analytic, self-consistent fashion for a set of periodic longitudinal space-charge potentials.

Commissioning and Early Operation Experience of the NSLS-II Storage Ring RF System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, F.; Rose, J.; Cupolo, J.

2015-05-03

The National Synchrotron Light Source II (NSLS-II) is a 3 GeV electron X-ray user facility commissioned in 2014. The storage ring RF system, essential for replenishing energy loss per turn of the electrons, consists of digital low level RF controllers, 310 kW CW klystron transmitters, CESR-B type superconducting cavities, as well as a supporting cryogenic system. Here we will report on RF commissioning and early operation experience of the system for beam current up to 200mA.

A 1kW EUV source for lithography based on FEL emission in a compact storage ring

NASA Astrophysics Data System (ADS)

Feser, Michael; Ruth, Ron; Loewen, Rod

2017-10-01

EUV has long been hailed as the next generation lithography technology. Its adoption into high volume manufacturing (HVM), however, has been delayed several technology nodes due to technical issues, many of which can be attributed to the EUV source performance. Today's EUV lithography scanners are powered by laser produce plasma (LPP) sources. They have issues with power scaling beyond 300 W, reliability and contamination. Free Electron Lasers (FELs) have been considered as an alternative EUV source. Advantages of accelerator based sources are the maturity of the accelerator technology, lack of debris/contamination, and ability to provide high power. Industry turned away from this technology because of the requirement to feed up to 10 scanners from one linear FEL to make it economically feasible, the large footprint, and generation of radioactive byproducts. All of these issues are overcome in the presented concept using a compact storage ring with steady-state FEL lasing action. At 1 kW output power, comparable cost and footprint to an LPP source, this source is ideally suited for use on a single scanner and promises reliable, contamination free operation. FEL action in the storage ring is sustained by operating the FEL well below the saturation regime and preserving the equilibrium low emittance and energy distribution of the ring.

Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

NASA Astrophysics Data System (ADS)

Xu, Wei; Li, Jing-Yi; Huang, Sen-Lin; Z. Wu, W.; Hao, H.; P., Wang; K. Wu, Y.

2014-10-01

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

Mass Measurements of Proton-rich Nuclides at the Cooler Storage Ring at IMP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y. H.; Xu, H. S.; Wang, M.

2011-11-30

Recent results and progress of mass measurements of proton-rich nuclei using isochronous mass spectrometry (IMS) are reported. The nuclei under investigation were produced via fragmentation of relativistic energy heavy ions of {sup 78}Kr and {sup 58}Ni. After in-flight separation by the fragment separator RIBLL-2, the nuclei were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of the revolution times. The impact of these measurements on the stellar nucleosynthesis in the rp-process is discussed.

The design improvement of horizontal stripline kicker in TPS storage ring

NASA Astrophysics Data System (ADS)

Chou, P. J.; Chan, C. K.; Chang, C. C.; Hsu, K. T.; Hu, K. H.; Kuan, C. K.; Sheng, I. C.

2017-07-01

We plan to replace the existing horizontal stripline kicker of the transverse feedback system with an improved design. Large reflected power was observed at the downstream port of stripline kicker driven by the feedback amplifier. A rapid surge of vacuum pressure was observed when we tested the high current operation in TPS storage ring in April 2016. A burned feedthrough of the horizontal stripline kicker was discovered during a maintenance shutdown. The improved design is targeted to reduce the reflection of driving power from feedback system and to reduce beam induced RF heating. This major modification of the design is described. The results of RF simulation performed with the electromagnetic code GdfidL are reported as well.

Beamline front end for in-vacuum short period undulator at the photon factory storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyauchi, Hiroshi, E-mail: hiroshi.miyauchi@kek.jp; Department of Accelerator Science, School of High Energy Accelerator Science, SOKENDAI; Tahara, Toshihiro, E-mail: ttahara@post.kek.jp

The straight-section upgrade project of the Photon Factory created four new short straight sections capable of housing in-vacuum short period undulators. The first to fourth short period undulators SGU#17, SGU#03, SGU#01 and SGU#15 were installed at the 2.5-GeV Photon Factory storage ring in 2005, 2006, 2009 and 2013, respectively. The beamline front end for SGU#15 is described in this paper.

The terminal Eocene event - Formation of a ring system around the earth

NASA Technical Reports Server (NTRS)

Okeefe, J. A.

1980-01-01

It is suggested that the formation of a ring system about the earth by particles and debris related to the North American strewn tektite field is responsible for the terminal Eocene event of 34 million years ago, in which severe climatic changes accompanied by widespread biological extinctions occurred. Botanical data is cited which implies a 20-C decrease in winter temperature with no change in summer temperature, and evidence of the correlation of the North American tektite fall, which is estimated to have a total mass of 10 to the 9th to 10 to the 10th tons, with the disappearance of five of the most abundant species of radiolaria is presented. The possible connection between the tektites and climatic change is argued to result from the screening of sunlight by an equatorial ring of trapped particles of extraterrestrial origin in geocentric orbit which would cut off sunlight only in the winter months. Such a ring, located at a distance of between 1.5 and 2.5 earth radii (the Roche limit) is estimated to have a lifetime of a few million years.

Coupling tree rings and eddy covariance to estimate long-term above and belowground carbon storage at the stand level

NASA Astrophysics Data System (ADS)

Dye, A.; Alexander, M. R.; Bishop, D.; Pederson, N.; Hessl, A. E.

2016-12-01

Storage of carbon in terrestrial plants and soils directly reduces atmospheric carbon concentration, and it is thereby imperative to improve our understanding of where carbon is being stored and released in an ecosystem and how storages and releases are changing over time. At data-rich sites, coupling alternative measurements of carbon flux can improve this understanding. Here, we present a methodology to inversely model stand-level net storage and release of above- and belowground carbon over a period of 1-2 decades using co-located tree-ring plots and eddy covariance towers at three eastern U.S. forests. We reconstructed annual aboveground wood production (aNPP) from tree rings collected near eddy covariance towers. We compared our aNPP reconstructions with annual tower NEE to address whether interannual variations are correlated. Despite modest correlation, we observed magnitude differences between both records that vary annually. We interpret these differences as indicative of changes in belowground carbon storage, i.e. an aNPP:NEE ratio > 1 indicates a net release of belowground carbon and a ratio < 1 a net storage of belowground carbon. For this interpretation, we assume the following: a) carbon not directed to above or belowground pools is insignificant, b) carbon not stored above ground is stored below ground, and c) mature trees do not add to a storage pool at a higher level every year. While the offset between biometric aNPP and tower NEE could partially be attributed to the diversion of assimilated carbon to nonstructural carbohydrates instead of growth, we argue that this becomes a less important factor over longer time scales in a mature tree. Our approach does not quantify belowground NPP or allocation, but we present a method for estimating belowground carbon storage and release at the stand level, an otherwise difficult task at this scale due to heterogeneity across the stand.

Inertial energy storage device

DOEpatents

Knight, Jr., Charles E.; Kelly, James J.; Pollard, Roy E.

1978-01-01

The inertial energy storage device of the present invention comprises a composite ring formed of circumferentially wound resin-impregnated filament material, a flanged hollow metal hub concentrically disposed in the ring, and a plurality of discrete filament bandsets coupling the hub to the ring. Each bandset is formed of a pair of parallel bands affixed to the hub in a spaced apart relationship with the axis of rotation of the hub being disposed between the bands and with each band being in the configuration of a hoop extending about the ring along a chordal plane thereof. The bandsets are disposed in an angular relationship with one another so as to encircle the ring at spaced-apart circumferential locations while being disposed in an overlapping relationship on the flanges of the hub. The energy storage device of the present invention has the capability of substantial energy storage due to the relationship of the filament bands to the ring and the flanged hub.

Theoretical study of hydrogen storage in a truncated triangular pyramid molecule consisting of pyridine and benzene rings bridged by vinylene groups

NASA Astrophysics Data System (ADS)

Ishikawa, Shigeru; Nemoto, Tetsushi; Yamabe, Tokio

2018-06-01

Hydrogen storage in a truncated triangular pyramid molecule C33H21N3, which consists of three pyridine rings and one benzene ring bridged by six vinylene groups, is studied by quantum chemical methods. The molecule is derived by substituting three benzene rings in a truncated tetrahedron hydrocarbon C36H24 with pyridine rings. The optimized molecular structure under C 3v symmetry shows no imaginary vibrational modes at the B3LYP/cc-pVTZ level of theory. The hydrogen storage process is investigated based on the MP2/cc-pVTZ method. Like the structure before substitution, the C33H21N3 molecule has a cavity that stores a hydrogen molecule with a binding energy of - 140 meV. The Langmuir isotherm shows that this cavity can store hydrogen at higher temperatures and lower pressures than usual physisorption materials. The C33H21N3 molecule has a kinetic advantage over the C36H24 molecule because the former molecule has a lower barrier (+ 560 meV) for the hydrogen molecule entering the cavity compared with the latter molecule (+ 730 meV) owing to the lack of hydrogen atoms narrowing the opening.

Conditioning of the vacuum system of the TPS storage ring without baking in situ

NASA Astrophysics Data System (ADS)

Chan, C. K.; Chang, C. C.; Shueh, C.; Yang, I. C.; Wu, L. H.; Chen, B. Y.; Cheng, C. M.; Huang, Y. T.; Chuang, J. Y.; Cheng, Y. T.; Hsiao, Y. M.; Sheng, Albert

2017-04-01

To shorten the machine downtime, a maintenance procedure without baking in situ has been developed and applied to maintain and to upgrade the vacuum system of the TPS storage ring. The data of photon-stimulated desorption (PSD) reveal no obvious discrepancy between baking and not baking the vacuum system in situ. A beam-conditioning dose of extent only 11.8 A h is required to recover quickly the dynamic pressure of an unbaked vacuum system to its pre-intervention value according to the TPS maintenance experience.

Collective Effects in a Diffraction Limited Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagaoka, Ryutaro; Bane, Karl L.F.

Our paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a seriesmore » of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head-tail and microwave instabilities. Additionally, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.« less

Collective Effects in a Diffraction Limited Storage Ring

DOE PAGES

Nagaoka, Ryutaro; Bane, Karl L.F.

2015-10-20

Our paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a seriesmore » of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head-tail and microwave instabilities. Additionally, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.« less

Software package for modeling spin-orbit motion in storage rings

NASA Astrophysics Data System (ADS)

Zyuzin, D. V.

2015-12-01

A software package providing a graphical user interface for computer experiments on the motion of charged particle beams in accelerators, as well as analysis of obtained data, is presented. The software package was tested in the framework of the international project on electric dipole moment measurement JEDI (Jülich Electric Dipole moment Investigations). The specific features of particle spin motion imply the requirement to use a cyclic accelerator (storage ring) consisting of electrostatic elements, which makes it possible to preserve horizontal polarization for a long time. Computer experiments study the dynamics of 106-109 particles in a beam during 109 turns in an accelerator (about 1012-1015 integration steps for the equations of motion). For designing an optimal accelerator structure, a large number of computer experiments on polarized beam dynamics are required. The numerical core of the package is COSY Infinity, a program for modeling spin-orbit dynamics.

Resonant beam behavior studies in the Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Holmes, J.; Galambos, J.; Fedotov, A.; Wei, J.; Macek, R.

2003-07-01

We present studies of space-charge-induced beam profile broadening at high intensities in the Proton Storage Ring (PSR) at Los Alamos National Laboratory. We investigate the profile broadening through detailed particle-in-cell simulations of several experiments and obtain results in good agreement with the measurements. We interpret these results within the framework of coherent resonance theory. With increasing intensity, our simulations show strong evidence for the presence of a quadrupole-mode resonance of the beam envelope with the lattice in the vertical plane. Specifically, we observe incoherent tunes crossing integer values, and large amplitude, nearly periodic envelope oscillations. At the highest operating intensities, we observe a continuing relaxation of the beam through space charge forces leading to emittance growth. The increase of emittance commences when the beam parameters encounter an envelope stop band. Once the stop band is reached, the emittance growth balances the intensity increase to maintain the beam near the stop band edge. Additionally, we investigate the potential benefit of a stop band correction to the high intensity PSR beam.

Large diameter metal ring seal prevents gas leakage at 5000 psi

NASA Technical Reports Server (NTRS)

Middelkoop, J. H.

1966-01-01

Large metal ring seal prevents gas leakage in hydrogen, helium, or nitrogen storage bottles at pressures up to 5,000 psi. The grooved ring seal which contains elastomer O-rings is installed between the mating faces of the access cover and the storage bottle.

Resonant neutral-particle emission in collisions of electrons with peptide ions in a storage ring.

PubMed

Tanabe, T; Noda, K; Saito, M; Lee, S; Ito, Y; Takagi, H

2003-05-16

Electron-biomolecular ion collisions were studied using an electrostatic storage ring with a merging beam technique for singly protonated peptides (angiotensin I, II, and III). A strong neutral-particle emission at around 6.5 eV was found in addition to neutrals from recombination at low energies. The rates of the high-energy peak greatly decreased with a slight decrease in the number of amino-acid residues from angiotensin I to III. These results suggest that some peptide bonds were selectively cleaved.

Radiological considerations for the operation of the Advanced Photon Source storage ring (revised).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, H. J.

2002-05-02

This report deals with the radiological considerations of operations using 7700-MeV positron and electron beams in the storage ring (SR) tunnel. The radiological considerations addressed include the following: prompt secondary radiation (bremsstrahlung, giant resonance neutrons, medium and high energy neutrons, and muons) produced by electrons/positrons interacting in a beam stop or by particle losses in the component structures; skyshine radiation, which produces a radiation field in nearby areas and at the nearest off-site location; radioactive gases produced by neutron irradiation of air in the vicinity of a particle loss site; noxious gases (ozone and others) produced in air by themore » escaping bremsstrahlung radiation that results from absorbing particles in the components or by synchrotron radiation escaping into the tunnel; activation of the storage ring components that results in a residual radiation field in the vicinity of these materials following shutdown; potential activation of water used for cooling the magnets and other purposes in the SR tunnel; evaluation of the radiation fields due to escaping synchrotron radiation and gas bremsstrahlung. Estimated dose rates outside of the tunnel, in the early assembly area (EAA), and in the Experiment Hall for several modes of operation (including potential safety envelope beam power, normal beam power, and MCI (maximum credible incident) conditions) have been computed. Shielding in the first optics enclosure (FOE) and for the photon beamlines is discussed in ANL/APS/TB-7 (IPE 93), but additional radiological considerations for the ASD diagnostic beamlines are contained in Appendix C. Although the calculations refer to positrons, electron operation would produce essentially the same effects for the identical assumptions.« less

Patterns of Storage, Synthesis and Changing Light Levels Revealed by Carbon Isotope Microsampling within Eocene Metasequoia Tree Rings

NASA Astrophysics Data System (ADS)

Jahren, H.; Sternberg, L.

2005-12-01

Fossil tree rings from Axel Heiberg Island were microanalyzed for δ13C value in order to assess patterns of tree growth and carbon storage within the Middle Eocene (~45 Ma) Arctic paleoenvironment. Wood from four Metasequoia-type individuals was subsampled for analysis: each individual fossil consisted of between 4 and 10 large (~1 cm thick) consecutive tree rings. One of the fossils displayed an obvious concentric pattern, allowing for the determination of the direction of growth with isotopic pattern. Each ring was divided into ~1 mm thick subsamples, resulting in 5-10 δ13C value determinations per period of ring growth (i.e., growing season). All rings revealed a distinct pattern that was characteristic across growing seasons and across individual fossils. Early in the season, δ13C was at its highest value but descended systematically and sharply to its lowest value at the end of the growing season. Total decrease ranged between 3 and 5 ‰ over the course of each growing season. Identical patterns were observed in the δ13C value of alpha-cellulose isolated from each subsample, indicating that the trends observed did not represent changing levels of secondary metabolites, but rather a seasonal adjustment in the bulk source of carbon used during biosynthesis. Our results are consistent with the following annual pattern of wood synthesis 1.) complete dependence on the mobilization of stored carbon compounds early in the growing season; 2.) systematically increasing use of actively-acquired photosynthate during the growing season; 3.) complete reliance on active photosynthate by the end of the growing season. An additional and significant source of 13C discrimination is declining light levels late in the growing season, and likely contributes to the extreme pattern of δ13C decrease seen across each ring. Our results mimic those seen from modern broadleaf deciduous trees (Helle & Schlesser 2004), but differ from those seen in modern conifers (Barbour et al 2002

CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

NASA Astrophysics Data System (ADS)

Najafi, M. A.; Dillmann, I.; Bosch, F.; Faestermann, T.; Gao, B.; Gernhäuser, R.; Kozhuharov, C.; Litvinov, S. A.; Litvinov, Yu. A.; Maier, L.; Nolden, F.; Popp, U.; Sanjari, M. S.; Spillmann, U.; Steck, M.; Stöhlker, T.; Weick, H.

2016-11-01

A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE / E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

Software package for modeling spin–orbit motion in storage rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zyuzin, D. V., E-mail: d.zyuzin@fz-juelich.de

2015-12-15

A software package providing a graphical user interface for computer experiments on the motion of charged particle beams in accelerators, as well as analysis of obtained data, is presented. The software package was tested in the framework of the international project on electric dipole moment measurement JEDI (Jülich Electric Dipole moment Investigations). The specific features of particle spin motion imply the requirement to use a cyclic accelerator (storage ring) consisting of electrostatic elements, which makes it possible to preserve horizontal polarization for a long time. Computer experiments study the dynamics of 10{sup 6}–10{sup 9} particles in a beam during 10{supmore » 9} turns in an accelerator (about 10{sup 12}–10{sup 15} integration steps for the equations of motion). For designing an optimal accelerator structure, a large number of computer experiments on polarized beam dynamics are required. The numerical core of the package is COSY Infinity, a program for modeling spin–orbit dynamics.« less

DESY II, a new injector for the DESY storage rings PETRA and DORIS II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemmie, G.

1983-08-01

There is a proposal to build a new 9 GeV electron synchrotron as a dedicated injector for the storage rings DORIS and PETRA. This machine will be housed in the old DESY-tunnel side-by-side with the original DESY-synchrotron. It is characterized by a separated function lattice, a 12.5 Hz repetition frequency, an all-metal vacuum chamber and a high shunt impedance rf-system. After commissioning of this new machine in 1984, the old DESY-synchrotron could be converted into a dedicated proton-accelerator as part of the injection chain for HERA.

Corrections for a constant radial magnetic field in the muon \\varvec{g}-2 and electric-dipole-moment experiments in storage rings

NASA Astrophysics Data System (ADS)

Silenko, Alexander J.

2017-10-01

We calculate the corrections for constant radial magnetic field in muon {g}-2 and electric-dipole-moment experiments in storage rings. While the correction is negligible for the current generation of {g}-2 experiments, it affects the upcoming muon electric-dipole-moment experiment at Fermilab.

OPERATIONAL EXPERIENCE WITH FAST FIBER-OPTIC BEAM LOSS MONITORS FOR THE ADVANCED PHOTON SOURCE STORAGE RING SUPERCONDUCTING UNDULATORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooling, J.; Harkay, K.; Sajaev, V.

Fast fiber-optic (FFO) beam loss monitors (BLMs) installed with the first two superconducting undulators (SCUs) in the Advanced Photon Source storage ring have proven to be a useful diagnostic for measuring deposited charge (energy) during rapid beam loss events. The first set of FFOBLMs were installed outside the cryostat of the short SCU, a 0.33-m long device, above and below the beam centerline. The second set are mounted with the first 1.1-mlong SCU within the cryostat, on the outboard and inboard sides of the vacuum chamber. The next 1.1-m-long SCU is scheduled to replace the short SCU later in 2016more » and will be fitted with FFOBLMs in a manner similar to original 1.1-m device. The FFOBLMs were employed to set timing and voltage for the abort kicker (AK) system. The AK helps to prevent quenching of the SCUs during beam dumps [1] by directing the beam away from the SC magnet windings. The AK is triggered by the Machine Protection System (MPS). In cases when the AK fails to prevent quenching, the FFOBLMs show that losses often begin before detection by the MPS.« less

Lifetimes of relativistic heavy-ion beams in the High Energy Storage Ring of FAIR

NASA Astrophysics Data System (ADS)

Shevelko, V. P.; Litvinov, Yu. A.; Stöhlker, Th.; Tolstikhina, I. Yu.

2018-04-01

The High Energy Storage Ring, HESR, will be constructed at the Facility for Antiproton and Ion Research, FAIR, Darmstadt. For the first time, it will be possible to perform experiments with cooled high-intensity stable and radioactive heavy ions at highly relativistic energies. To design experiments at the HESR, realistic estimations of beam lifetimes are indispensable. Here we report calculated cross sections and lifetimes for typical U88+ , U90+ , U92+ , Sn49+ and Sn50+ ions in the energy range E = 400 MeV/u-5 GeV/u, relevant for the HESR. Interactions with the residual gas and with internal gas-jet targets are also considered.

Investigation of the heavy-ion mode in the FAIR High Energy Storage Ring

NASA Astrophysics Data System (ADS)

Kovalenko, O.; Dolinskii, O.; Litvinov, Yu A.; Maier, R.; Prasuhn, D.; Stöhlker, T.

2015-11-01

High energy storage ring (HESR) as a part of the future accelerator facility FAIR (Facility for Antiproton and Ion Research) will serve for a variety of internal target experiments with high-energy stored heavy ions (SPARC collaboration). Bare uranium is planned to be used as a primary beam. Since a storage time in some cases may be significant—up to half an hour—it is important to examine the high-order effects in the long-term beam dynamics. A new ion optics specifically for the heavy ion mode of the HESR is developed and is discussed in this paper. The subjects of an optics design, tune working point and a dynamic aperture are addressed. For that purpose nonlinear beam dynamics simulations are carried out. Also a flexibility of the HESR ion optical lattice is verified with regard to various experimental setups. Specifically, due to charge exchange reactions in the internal target, secondary beams, such as hydrogen-like and helium-like uranium ions, will be produced. Thus the possibility of separation of these secondary ions and the primary {{{U}}}92+ beam is presented with different internal target locations.

Suppression of alpha-induced lateral surface events in the COBRA experiment using CdZnTe detectors with an instrumented guard-ring electrode

NASA Astrophysics Data System (ADS)

Arling, J.-H.; Gerhardt, M.; Gößling, C.; Gehre, D.; Klingenberg, R.; Kröninger, K.; Nitsch, C.; Quante, T.; Rohatsch, K.; Tebrügge, J.; Temminghoff, R.; Theinert, R.; Zatschler, S.; Zuber, K.

2017-11-01

The COBRA collaboration searches for neutrinoless double beta-decay (0νββ-decay) using CdZnTe semiconductor detectors with a coplanar-grid readout and a surrounding guard-ring structure. The operation of the COBRA demonstrator at the Gran Sasso underground laboratory (LNGS) indicates that alpha-induced lateral surface events are the dominant source of background events. By instrumenting the guard-ring electrode it is possible to suppress this type of background. In laboratory measurements this method achieved a suppression factor of alpha-induced lateral surface events of 5300+2660-1380, while retaining (85.3 ±0.1%) of gamma events occurring in the entire detector volume. This suppression is superior to the pulse-shape analysis methods used so far in COBRA by three orders of magnitude.

Broadband impedance calculations and single bunch instabilities estimations of of the HLS-II storage ring

NASA Astrophysics Data System (ADS)

Zhang, Qing-Kun; Wang, Lin; Li, Wei-Min; Gao, Wei-Wei

2015-12-01

The upgrade project of the Hefei Light Source storage ring is under way. In this paper, the broadband impedances of resistive wall and coated ceramic vacuum chamber are calculated using the analytic formula, and the wake fields and impedances of other designed vacuum chambers are simulated by CST code, and then a broadband impedance model is obtained. Using the theoretical formula, longitudinal and transverse single bunch instabilities are discussed. With the carefully-designed vacuum chamber, we find that the thresholds of the beam instabilities are higher than the beam current goal. Supported by Natural Science Foundation of China (11175182, 11175180)

Dissociative recombination measurements of NH{sup +} using an ion storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novotný, O.; Savin, D. W.; Berg, M.

We have investigated dissociative recombination (DR) of NH{sup +} with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present our measured absolute merged-beams recombination rate coefficient for collision energies from 0 to 12 eV. From these data, we have extracted a cross section, which we have transformed to a plasma rate coefficient for the collisional plasma temperature range from T {sub pl} = 10 to 18,000 K. We show that the NH{sup +} DR rate coefficient data in current astrochemical models are underestimatedmore » by up to a factor of approximately nine. Our new data will result in predicted NH{sup +} abundances lower than those calculated by present models. This is in agreement with the sensitivity limits of all observations attempting to detect NH{sup +} in interstellar clouds.« less

New beam-position monitor system for upgraded Photon Factory storage ring.

PubMed

Haga, K; Honda, T; Tadano, M; Obina, T; Kasuga, T

1998-05-01

Accompanying the brilliance-upgrading project at the Photon Factory storage ring, the beam-position monitor (BPM) system has been renovated. The new system was designed to enable precise and fast measurements to correct the closed-orbit distortion (COD), as well as to feed back the orbit position during user runs. There are 42 BPMs newly installed, amounting to a total of 65 BPMs. All of the BPMs are calibrated on the test bench using a coaxially strung metallic wire. The measured electrical offsets are typically 200 micro m in both directions, which is 1/2-1/3 of those of the old-type BPMs. In the signal-processing system, PIN diode switches are employed in order to improve reliability. In the fastest mode, this system is capable of measuring COD within about 10 ms; this fast acquisition will allow fast suppression of the beam movement for frequencies up to 50 Hz using a global feedback system.

Calibration of Fast Fiber-Optic Beam Loss Monitors for the Advanced Photon Source Storage Ring Superconducting Undulators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooling, J.; Harkay, K.; Ivanyushenkov, Y.

2015-01-01

We report on the calibration and use of fast fiber-optic (FO) beam loss monitors (BLMs) in the Advanced Photon Source storage ring (SR). A superconducting undulator prototype (SCU0) has been operating in SR Sector 6 (“ID6”) since the beginning of CY2013, and another undulator SCU1 (a 1.1-m length undulator that is three times the length of SCU0) is scheduled for installation in Sector 1 (“ID1”) in 2015. The SCU0 main coil often quenches during beam dumps. MARS simulations have shown that relatively small beam loss (<1 nC) can lead to temperature excursions sufficient to cause quenchingwhen the SCU0windings are nearmore » critical current. To characterize local beam losses, high-purity fused-silica FO cables were installed in ID6 on the SCU0 chamber transitions and in ID1 where SCU1 will be installed. These BLMs aid in the search for operating modes that protect the SCU structures from beam-loss-induced quenching. In this paper, we describe the BLM calibration process that included deliberate beam dumps at locations of BLMs. We also compare beam dump events where SCU0 did and did not quench.« less

Three-dimensional ordering of cold ion beams in a storage ring: A molecular-dynamics simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuri, Yosuke, E-mail: yuri.yosuke@jaea.go.jp

Three-dimensional (3D) ordering of a charged-particle beams circulating in a storage ring is systematically studied with a molecular-dynamics simulation code. An ion beam can exhibit a 3D ordered configuration at ultralow temperature as a result of powerful 3D laser cooling. Various unique characteristics of the ordered beams, different from those of crystalline beams, are revealed in detail, such as the single-particle motion in the transverse and longitudinal directions, and the dependence of the tune depression and the Coulomb coupling constant on the operating points.

Impact parameter sensitive study of inner-shell atomic processes in the experimental storage ring

NASA Astrophysics Data System (ADS)

Gumberidze, A.; Kozhuharov, C.; Zhang, R. T.; Trotsenko, S.; Kozhedub, Y. S.; DuBois, R. D.; Beyer, H. F.; Blumenhagen, K.-H.; Brandau, C.; Bräuning-Demian, A.; Chen, W.; Forstner, O.; Gao, B.; Gassner, T.; Grisenti, R. E.; Hagmann, S.; Hillenbrand, P.-M.; Indelicato, P.; Kumar, A.; Lestinsky, M.; Litvinov, Yu. A.; Petridis, N.; Schury, D.; Spillmann, U.; Trageser, C.; Trassinelli, M.; Tu, X.; Stöhlker, Th.

2017-10-01

In this work, we present a pilot experiment in the experimental storage ring (ESR) at GSI devoted to impact parameter sensitive studies of inner shell atomic processes for low-energy (heavy-) ion-atom collisions. The experiment was performed with bare and He-like xenon ions (Xe54+, Xe52+) colliding with neutral xenon gas atoms, resulting in a symmetric collision system. This choice of the projectile charge states was made in order to compare the effect of a filled K-shell with the empty one. The projectile and target X-rays have been measured at different observation angles for all impact parameters as well as for the impact parameter range of ∼35-70 fm.

Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillwell, B.; Brajuskovic, B.; Carter, J.

A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Up-grade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation; insufficient beam position monitor stability; excessive beam impedance; excessive heating by induced electrical surface currents; and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mockup assemblies; performing mechanical testing of chamber weld joints; developing computational tools; investigating design alternatives; and performing electrical bench measurements. Status of these activities andmore » some of what has been learned to date will be shared.« less

Missing Rings in Pinus halepensis - The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events.

PubMed

Novak, Klemen; de Luis, Martin; Saz, Miguel A; Longares, Luis A; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B K; Papadopoulos, Andreas; Smith, Kevin T

2016-01-01

Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

Construction and operation of a support facilities (Building 729) for operation/testing of a prototype accelerator/storage ring (XLS) and machine shop for the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-06-01

Proposed action is to construct at BNL a 5,600-ft[sup 2] support building, install and operate a prototypic 200 MeV accelerator and a prototypic 700 MeV storage ring within, and to construct and operate a 15 kV substation to power the building. The accelerator and storage ring would comprise the x-ray lithography source or XLS.

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe{sup 7+}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, M.; Novotný, O.; Savin, D. W.

2015-11-01

We have measured electron impact ionization for Fe{sup 7+} from the ionization threshold up to 1200 eV. The measurements were performed using the TSR heavy ion storage ring. The ions were stored long enough prior to measurements to remove most metastables, resulting in a beam of 94% ground-level ions. Comparing with the previously recommended atomic data, we find that the Arnaud and Raymond cross section is up to about 40% larger than our measurement, with the largest discrepancies below about 400 eV. The cross section of Dere agrees to within 10%, which is about the magnitude of the experimental uncertainties.more » The remaining discrepancies between our measurement and the Dere calculations are likely due to shortcomings in the theoretical treatment of the excitation-autoionization contribution.« less

Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

NASA Astrophysics Data System (ADS)

Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

2017-08-01

Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

Direct Observation of Spatiotemporal Dynamics of Short Electron Bunches in Storage Rings

NASA Astrophysics Data System (ADS)

Evain, C.; Roussel, E.; Le Parquier, M.; Szwaj, C.; Tordeux, M.-A.; Brubach, J.-B.; Manceron, L.; Roy, P.; Bielawski, S.

2017-02-01

In recent synchrotron radiation facilities, the use of short (picosecond) electron bunches is a powerful method for producing giant pulses of terahertz coherent synchrotron radiation. Here we report on the first direct observation of these pulse shapes with a few picoseconds resolution, and of their dynamics over a long time. We thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses (a broadband Terahertz comb) stemming from the shortness of the electron bunches. Above this threshold, a large part of the emission is dominated by drifting structures, which appear through spontaneous self-organization. These challenging single-shot THz recordings are made possible by using a recently developed photonic time stretch detector with a high sensitivity. The experiment has been realized at the SOLEIL storage ring.

Introduction to the magnet and vacuum systems of an electron storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weng, W.T.

An accelerator or storage ring complex is a concerted interplay of various functional systems. For the convenience of discussion we can divide it into the following systems: injector, magnet, RF, vacuum, instrumentation and control. In addition, the conventional construction of the building and radiation safety consideration are also needed and finally the beam lines, detector, data acquisition and analysis set-ups for research programs. Dr. L. Teng has given a comprehensive review of the whole complex and the operation of such a facility. I concentrate on the description of magnet and vacuum systems. Only the general function of each system andmore » the basic design concepts will be introduced, no detailed engineering practice will be given which will be best done after a machine design is produced. For further understanding and references a table of bibliography is provided at the end of the paper.« less

Duke storage rink UV/VUV FEL: Status and prospects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Litvinenko, V.N.; Burnham, B.; Madey, J.M.J.

1995-12-31

The 1 GeV Duke storage ring was successfully commissioned with parameters exceeding initial specification. The OK-4 FEL has arrived at the Duke FEL laboratory from the Novosibirsk Institute of Nuclear Physics. The OK-4 installation and commissioning is in progress. In this paper we describe the up-to-date status of the Duke storage ring and the OK-4 FEL. The projected performance of the OK-4 UV/VUV FEL is presented based on the electron beam parameters achieved. Initial plans to operate the OK-4 UV/VUV FEL at the Duke 1 GeV storage ring are outlined. Future plans and prospects of both the OK-4 FEL andmore » the Duke storage ring are discussed.« less

Saturation of the laser-induced narrowband coherent synchrotron radiation process: Experimental observation at a storage ring

NASA Astrophysics Data System (ADS)

Hosaka, M.; Yamamoto, N.; Takashima, Y.; Szwaj, C.; Le Parquier, M.; Evain, C.; Bielawski, S.; Adachi, M.; Zen, H.; Tanikawa, T.; Kimura, S.; Katoh, M.; Shimada, M.; Takahashi, T.

2013-02-01

We study the efficiency limitation affecting laser-induced coherent synchrotron radiation (CSR) at high laser power. Experiments are made on the UVSOR-II storage ring in conditions of narrowband terahertz CSR emission. While, at moderate power, CSR power increases quadratically with laser power, a noticeable decrease in efficiency and eventually a decrease in CSR power is observed experimentally at high power. Details of the underlying process are analyzed numerically. As the saturation effect depends almost instantaneously on the laser intensity, the saturation occurs locally in longitudinal space. This has important consequences on the modulation pattern induced on the electron bunch.

Millimeter wave coherent synchrotron radiation in a compact electron storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, J.B.; Blum, E.; Heese, R.

1998-01-01

Installation of a 2,856 MHz RF system into the XLS compact electron storage ring would allow the generation of millimeter wave coherent synchrotron radiation. Operating at 150 MeV, one could produce bunches containing on the order of 2 {times} 10{sup 7} electrons with a bunch length {sigma}{sub L0} = 0.3 mm, resulting in coherent emission at wavelengths above 0.8 mm. The characteristics of the source and the emitted radiation are discussed. In the case of 100 mrad horizontal collection angle, the average power radiated in the wavelength band 1 mm {le} {lambda} {le} 2 mm is 0.3 mW for singlemore » bunch operation and 24 mW for 80 bunch operation. The peak power in a single pulse of a few picosecond duration is on the order of one watt. By reducing the momentum compaction, the bunch length could be reduced to {sigma}{sub L0} = 0.15 mm, resulting in coherent synchrotron radiation down to 500 {micro}m.« less

DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl{sup +} USING AN ION STORAGE RING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novotný, O.; Stützel, J.; Savin, D. W.

We have measured dissociative recombination (DR) of HCl{sup +} with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present the measured absolute merged beams recombination rate coefficient for collision energies from 0 to 4.5 eV. We have also developed a new method for deriving the cross section from the measurements. Our approach does not suffer from approximations made by previously used methods. The cross section was transformed to a plasma rate coefficient for the electron temperature range from T = 10 to 5000more » K. We show that the previously used HCl{sup +} DR data underestimate the plasma rate coefficient by a factor of 1.5 at T = 10 K and overestimate it by a factor of three at T = 300 K. We also find that the new data may partly explain existing discrepancies between observed abundances of chlorine-bearing molecules and their astrochemical models.« less

Analytical approach to Eigen-emittance evolution in storage rings

NASA Astrophysics Data System (ADS)

Nash, Boaz

This dissertation develops the subject of beam evolution in storage rings with nearly uncoupled symplectic linear dynamics. Linear coupling and dissipative/diffusive processes are treated perturbatively. The beam distribution is assumed Gaussian and a function of the invariants. The development requires two pieces: the global invariants and the local stochastic processes which change the emittances, or averages of the invariants. A map based perturbation theory is described, providing explicit expressions for the invariants near each linear resonance, where small perturbations can have a large effect. Emittance evolution is determined by the damping and diffusion coefficients. The discussion is divided into the cases of uniform and non-uniform stochasticity, synchrotron radiation an example of the former and intrabeam scattering the latter. For the uniform case, the beam dynamics is captured by a global diffusion coefficent and damping decrement for each eigen-invariant. Explicit expressions for these quantities near coupling resonances are given. In many cases, they are simply related to the uncoupled values. Near a sum resonance, it is found that one of the damping decrements becomes negative, indicating an anti-damping instability. The formalism is applied to a number of examples, including synchrobetatron coupling caused by a crab cavity, a case of current interest where there is concern about operation near half integer betatron tune. In the non-uniform case, the moment evolution is computed directly, which is illustrated through the example of intrabeam scattering. Our approach to intrabeam scattering damping and diffusion has the advantage of not requiring a loosely-defined Coulomb Logarithm. It is found that in some situations there is a small difference between our results and the standard approaches such as Bjorken-Mtingwa, which is illustrated by comparison of the two approaches and with a measurement of Au evolution in RHIC. Finally, in combining IBS

Slowing down of ring polymer diffusion caused by inter-ring threading.

PubMed

Lee, Eunsang; Kim, Soree; Jung, YounJoon

2015-06-01

Diffusion of long ring polymers in a melt is much slower than the reorganization of their internal structures. While direct evidence for entanglements has not been observed in the long ring polymers unlike linear polymer melts, threading between the rings is suspected to be the main reason for slowing down of ring polymer diffusion. It is, however, difficult to define the threading configuration between two rings because the rings have no chain end. In this work, evidence for threading dynamics of ring polymers is presented by using molecular dynamics simulation and applying a novel analysis method. The simulation results are analyzed in terms of the statistics of persistence and exchange times that have proved useful in studying heterogeneous dynamics of glassy systems. It is found that the threading time of ring polymer melts increases more rapidly with the degree of polymerization than that of linear polymer melts. This indicates that threaded ring polymers cannot diffuse until an unthreading event occurs, which results in the slowing down of ring polymer diffusion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The contraceptive vaginal ring, NuvaRing(®), a decade after its introduction.

PubMed

Roumen, Frans J M E; Mishell, Daniel R

2012-12-01

To review the clinical experience with the contraceptive vaginal ring (CVR, NuvaRing(®)) since its introduction over ten years ago. The literature was searched on efficacy, cycle control, safety, user preference and satisfaction of the CVR in comparison with combined oral contraceptives (COCs) and the patch, with special attention to recent developments. The ring has the same working mechanism and contraindications as COCs. Serum levels of steroids are steadier, whereas oestrogenic exposure is lower. Contraceptive efficacy is similar, as are metabolic changes. Cycle control is better, and compliance and continuation rates are equal or higher. Oestrogen-related adverse symptoms appear to be fewer, but reports on the incidence of venous thrombosis are conflicting. Expulsion of the ring is reported by 4% to 20% of women. Local adverse events are the main reason for discontinuation. Acceptability is as high as with COCs and, after structured counselling, the ring is preferred by many women to the pill or the patch. Efficacy of the CVR, and the metabolic changes and adverse events it elicits, are generally comparable to those of COCs, yet oestrogenic exposure is lower and cycle control superior. After counselling, the ring is preferred to the pill by many women.

Missing Rings in Pinus halepensis – The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events

PubMed Central

Novak, Klemen; de Luis, Martin; Saz, Miguel A.; Longares, Luis A.; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B. K.; Papadopoulos, Andreas; Smith, Kevin T.

2016-01-01

Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

TSR: A storage and cooling ring for HIE-ISOLDE

NASA Astrophysics Data System (ADS)

Butler, P. A.; Blaum, K.; Davinson, T.; Flanagan, K.; Freeman, S. J.; Grieser, M.; Lazarus, I. H.; Litvinov, Yu. A.; Lotay, G.; Page, R. D.; Raabe, R.; Siesling, E.; Wenander, F.; Woods, P. J.

2016-06-01

It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

Ring-diameter Ratios for Multi-ring Basins Average 2.0(0.5)D

NASA Technical Reports Server (NTRS)

Pike, R. J.; Spudis, P. D.

1985-01-01

The spacing of the concentric rings of planetary impact basins was studied. It is shown that a radial increment of x (sup 0.5) D, where x is about 2.0 and D = ring diameter, separates both (1) adjacent least-squares groups of rings and arcs of multi-ring basins on Mars, Mercury, and the Moon; and (2) adjacent rings of individual basins on the three planets. Statistics for ratios of ring diameters are presented, the first and most-applied parameter of ring spacing. It is found that ratios excluding rings flanking the main ring also have a mean spacing increment of about 2.0. Ratios including such rings, as for the least-squares groups, and (1) above, have a larger increment, averaging 2.1. The F-test indicates, that these spacings of basin ring locations, and mode of ring formation are controlled by the mechanics of the impact event itself, rather than by crustal properties.

Construction and operation of a support facilities (Building 729) for operation/testing of a prototype accelerator/storage ring (XLS) and machine shop for the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, New York. Environmental assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-06-01

Proposed action is to construct at BNL a 5,600-ft{sup 2} support building, install and operate a prototypic 200 MeV accelerator and a prototypic 700 MeV storage ring within, and to construct and operate a 15 kV substation to power the building. The accelerator and storage ring would comprise the x-ray lithography source or XLS.

Oxygen Abundances in the Rings of Polar-Ring Galaxies

NASA Astrophysics Data System (ADS)

Radtke, I. R.; Eskridge, P. B.; Pogge, R. W.

2003-05-01

Polar ring galaxies (PRGs) are typically early-type (S0 or E) galaxies surrounded by rings of gas, dust, and stars orbiting nearly perpendicular to the principle plane of the host galaxy (Whitmore et al. 1990 AJ 100 1489). Given that PRGs have two separate, perpendicular axes of rotation, it is clear on dynamical grounds that PRGs are the products of merger events between two galaxies, but are observed in a state where two distinct kinematic and morphological structures are still apparent. As such, they present a unique opportunity to study merger events in systems where the debris is not confused with material from the host. Our understanding of the relative importance of polar ring systems in the overall process of galaxy evolution is confounded by our lack of knowledge regarding the typical lifetimes and evolutionary histories of polar rings. A crucial factor for understanding the formation and evolution of PRGs is information regarding the elemental abundances of the ring material. Polar rings are typically rich in {\\protectH 2} regions. Optical spectroscopy of these {\\protectH 2} regions can tell us their density, temperature, and oxygen abundance. Our earlier work (Eskridge & Pogge 1997 ApJ 486 259) revealed roughly Solar oxygen abundances for {\\protectH 2} regions in the polar ring of NGC 2685. We have extended this project, and now have spectra for six PRGs. Analysis of the data for II Zw 73 and UGC 7576 reveal the polar rings of these galaxies to have {\\protectH 2} region oxygen abundances in the range 0.3 to 0.6 Solar, substantially less than found for NGC 2685. Abundances in this range are much easier to explain with conventional models of chemical enrichment and polar ring formation. We shall present results for our full sample. Taken as a whole, this sample will provide a clear foundation for the typical chemical enrichment patterns in polar rings, and thus provide a clearer understanding of the formation and evolution of these curious objects. We

New waveguide-type HOM damper for ALS storage ring cavities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwiatkowski, Slawomir; Baptiste, Kenneth; Julian, James

2004-06-28

The ALS storage ring 500 MHz RF system uses two re-entrant accelerating cavities powered by a single 320kW PHILLIPS YK1305 klystron. During several years of initial operation, the RF cavities were not equipped with effective passive HOM damper systems. Longitudinal beam stability was achieved through cavity temperature control and the longitudinal feedback system (LFB), which was often operating at the edge of its capabilities. As a result, longitudinal beam stability was a significant operations issue at the ALS. During two consecutive shutdown periods (April 2002 and 2003) we installed E-type HOM dampers on the main and third harmonic cavities. Thesemore » devices dramatically decreased the Q-values of the longitudinal anti-symmetric HOM modes. The next step is to damp the rest of the longitudinal HOM modes in the main cavities below the synchrotron radiation damping level. This will hopefully eliminate the need for the LFB and set the stage for a possible increase in beam current. The ''waveguide'' type of HOM damper was the only option that didn't significantly compromise the vacuum performance of the RF cavity. The design process and the results of the low level measurements of the new waveguide dampers are presented in this paper.« less

Calculations of the conditions for bunch leakage in the Los Alamos proton storage ring

NASA Astrophysics Data System (ADS)

Neuffer, D.; Ohmori, C.

1994-04-01

Observations are consistent with the possibility of an "ep" instability in the Los Alamos Proton Storage Ring (PSR) with both bunched and unbunched beam. The instability requires electrons to be trapped within the beam, and calculations have shown that such trapping requires leakage of beam into the interbunch gap. Observationally, leakage of beam into the gap appears necessary for the onset of the instability. In this paper we present results of studies of the longitudinal beam dynamics at PSR parameters. The studies indicate that the combined effects of the rf buncher, longitudinal space charge, and injection mismatch are sufficient to cause the observed bunch leakage. Simulation results are presented and compared with PSR observations. Variations of PSR performance parameters are considered, and methods of improving bunch confinement are suggested and studied.

Flexible matrix composite laminated disk/ring flywheel

NASA Technical Reports Server (NTRS)

Gupta, B. P.; Hannibal, A. J.

1984-01-01

An energy storage flywheel consisting of a quasi-isotropic composite disk overwrapped by a circumferentially wound ring made of carbon fiber and a elastometric matrix is proposed. Through analysis it was demonstrated that with an elastomeric matrix to relieve the radial stresses, a laminated disk/ring flywheel can be designed to store a least 80.3 Wh/kg or about 68% more than previous disk/ring designs. at the same time the simple construction is preserved.

Tracing footprints of environmental events in tree ring chemistry using neutron activation analysis

NASA Astrophysics Data System (ADS)

Sahin, Dagistan

The aim of this study is to identify environmental effects on tree-ring chemistry. It is known that industrial pollution, volcanic eruptions, dust storms, acid rain and similar events can cause substantial changes in soil chemistry. Establishing whether a particular group of trees is sensitive to these changes in soil environment and registers them in the elemental chemistry of contemporary growth rings is the over-riding goal of any Dendrochemistry research. In this study, elemental concentrations were measured in tree-ring samples of absolutely dated eleven modern forest trees, grown in the Mediterranean region, Turkey, collected and dated by the Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology laboratory at Cornell University. Correlations between measured elemental concentrations in the tree-ring samples were analyzed using statistical tests to answer two questions. Does the current concentration of a particular element depend on any other element within the tree? And, are there any elements showing correlated abnormal concentration changes across the majority of the trees? Based on the detailed analysis results, the low mobility of sodium and bromine, positive correlations between calcium, zinc and manganese, positive correlations between trace elements lanthanum, samarium, antimony, and gold within tree-rings were recognized. Moreover, zinc, lanthanum, samarium and bromine showed strong, positive correlations among the trees and were identified as possible environmental signature elements. New Dendrochemistry information found in this study would be also useful in explaining tree physiology and elemental chemistry in Pinus nigra species grown in Turkey. Elemental concentrations in tree-ring samples were measured using Neutron Activation Analysis (NAA) at the Pennsylvania State University Radiation Science and Engineering Center (RSEC). Through this study, advanced methodologies for methodological, computational and

Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillwell, B.; Billett, B.; Brajuskovic, B.

2017-06-20

Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction and rf cavity straight sections. An overview of progress in these areas is presented.

Design of 3 GeV booster ring lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Etisken, O., E-mail: ozgur.etisken@cern.ch; Ciftci, A. K., E-mail: abbas.kenan.ciftci@cern.ch

2016-03-25

The aim of this study is to design of a 3 GeV booster ring for the 3 GeV storage ring. Electrons are needed to be accelerated to 3.0 GeV from 0.15 GeV energy. In this frame, we studied on two options for booster ring; a compact booster and the booster that shares the same tunnel with the storage ring. The lattice type has been chosen FODO for both options, lattice parameters are calculated, sextupole magnets are used to decrease dynamic aperture problem and dynamic aperture calculations are also made with considering of the necessary conditions. After designing and calculating ofmore » the parameters, these designs have been compared with each other. In addition to this comparison, these booster design parameters have been compared with some world centers design parameters and the reliability of the booster design is seen. Beam optics, OPA and Elegant simulation programs have been used in the study calculations.« less

Subauroral polarization stream on the outer boundary of the ring current during an energetic ion injection event

NASA Astrophysics Data System (ADS)

Yuan, Zhigang; Qiao, Zheng; Li, Haimeng; Huang, Shiyong; Wang, Dedong; Yu, Xiongdong; Yu, Tao

2017-04-01

Subauroral polarization stream (SAPS) electric field can play an important role in the coupling between the inner magnetosphere and ionosphere; however, the production mechanism of SAPS has not been yet solved. During an energetic ion injection event on 26 March 2004, at latitudes lower than the equatorward boundaries of precipitating plasma sheet electrons and ions, the Defense Meteorological Satellite Program (DMSP) F13 satellite simultaneously observed a strong SAPS with the peak velocity of 1294 m/s and downward flowing field-aligned currents (FACs). Conjugate observations of DMSP F13 and NOAA 15 satellites have shown that FACs flowing into the ionosphere just lie in the outer boundary of the ring current (RC). The downward flowing FACs were observed in a region of positive latitudinal gradients of the ion energy density, implying that the downward flowing FACs are more likely linked to the azimuthal gradient than the radial gradient of the RC ion pressure. Our result demonstrates that RC ion pressure gradients on the outer boundary of the RC in the evening sector during energetic ion injection events can lead to downward flowing FACs so as to cause strong SAPS in condition of low ionospheric conductivities.