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| TUPGW001 | Improvements to Injector System Efficiency at the Australian Synchrotron | 1378 |
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Funding: Australian Nuclear Science and Technology Organisation New instrumentation, software, and hardware upgrades have allowed Operations personnel to increase the overall injector system efficiency from 50% to 80% at the Australian Synchrotron. This paper will provide an overview of the methods used to achieve this result. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW001 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW003 | Sirius Status Update | 1381 |
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| Sirius is a 4th generation 3 GeV low emittance electron storage ring that is in its final installation phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. Presently the injector installation is complete, and the storage ring installation is being finalized. Most subsystems are under test and tuning in real working conditions. Six beamlines are also under construction. In this paper we report on the Sirius main subsystems installation status. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW003 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW004 | Cls 2.2: Ultra-Brilliant Round Beams Using Pseudo Longitudinal Gradient Bends | 1385 |
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| A preliminary design for a new storage for the Canadian Light Source was presented at IPAC’18 (Dallin). More recently a reconfigured lattice was presented at the 6th DLSR workshop. This lattice employed large βy and small βx in the straights. This has several advantages including: increased transverse coherence and brighter beams at small coupling; round beams at small coupling; flatter βy through the straights; and possible off-axis vertical injection at small amplitudes. Most recently longitudinal gradients in the dipoles have been implemented. This has lead to the unit cell bends being replaced by a ’pseudo longitudinal gradient’ bend array: bend1-bend2-bend1. This results in smaller emittance with simple magnet designs while maintaining adequate dynamic aperture for off-axis injection. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW004 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW005 | Preparation of the EBS Beam Commissioning | 1388 |
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| In 2020 the ESRF storage ring will be upgraded to a Hybrid Multi Bend Achromat (HMBA) lattice. The commissioning of the new ring will require dedicated tools, either updated from the existing ones or newly developed. Most of the software and procedures were tested on the existing storage ring before its decommissioning. In particular we present experiments on first-turn steering and beam accumulation, check of magnet polarity and calibration, and injection tuning. The use of a control-system simulator proved to be crucial for the debugging of the software and the development of the new control system, as far as beam measurements and manipulations are concerned. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW005 | |
| About • | paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW006 | Measurements of the Momentum Compaction Factor of the ESRF Storage Ring | 1392 |
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| In a storage ring, the momentum compaction factor can be obtained by measuring the variation of the beam energy as a function of the RF frequency. In this paper we present the measurement of the momentum compaction factor from two different methods. With the first, we measure the variation of the undulator spectra for different RF frequencies. With the second, we measure the variation of the hard x-rays flux produced by a dipole for different RF frequencies. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW006 | |
| About • | paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW008 | PERLE: A High Power Energy Recovery Facility | 1396 |
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| PERLE is a proposed high power Energy Recovery Linac, designed on multi-turn configuration, based on SRF technology, to be hosted at Orsay-France in a col-laborative effort between local laboratories: LAL and IPNO, together with an international collaboration involv-ing today: CERN, JLAB, STFC ASTeC Daresbury, Liverpool University and BINP Novosibirsk. PERLE will be a unique leading edge facility designed to push advances in accelerator technology, to provide intense and highly flexible test beams for component development. In its final configuration, PERLE provides a 500 MeV elec-tron beam using high current (20 mA) acceleration during three passes through 801.6 MHz cavities. This presenta-tion outlines the technological choices, the lattice design and the main component descriptions. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW008 | |
| About • | paper received ※ 19 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW009 | THE ESRF FROM 1988 TO 2018, 30 YEARS OF INNOVATION AND OPERATION | 1400 |
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| In 1988, eleven European countries joined forces to build the European Synchrotron Facility in Grenoble [France]. The ESRF was the first third-generation light source worldwide. After 30 years of innovation and user operation, the present storage ring was shut down to leave room for a new and brighter source. This paper describes the evolution of the facility from its origin to the Ex-tremely Bright Source (EBS). Firstly, the operational aspects including reliability and beam modes are consid-ered. This is followed by the presentation of the progress of lattice and the implementation of top-up. Finally, the development of the radio frequency and vacuum systems are discussed. To conclude, the lessons learned from 30 years operation are summarized, especially in view of EBS. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW009 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW011 | Status of the PETRA IV project | 1404 |
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| Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW012 | Sensitivity Studies of the PETRA IV Lattice | 1408 |
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| As the machine with the smallest emittance among the planned fourth-generation hard x-ray synchrotron light sources, PETRA IV will have very demanding requirements on magnet alignment and stability. Several developments to address mechanical and beam-based stabilization have been started in connection to that. Here we summarize the alignment and field error tollerances resulting from startup and commissioning simulations of the main ring. Novel high level control tools will be required to assure smooth operation of the machine; progress in their development and beam test results at PETRA III will be reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW012 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW013 | Tune and Chromaticity Optimization at Bessy II for the Transverse Resonant Island Bucket Optics | 1411 |
| SUSPFO012 | use link to see paper's listing under its alternate paper code | |
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Funding: Federal Ministry of Education and Research Transverse Resonant Island Buckets (TRIBs *) correspond to a second stable orbit, longitudinally winding around the core orbit in the transverse x-x′-phasespace. The exploitation possibilities for stable TRIBs are under investigation at the third generation light source BESSY II in Berlin. The applicability for bunch separation is a main subject of these studies. Stable operation of TRIBs optics with a single or few bunches on the second orbit and a multibunch train on the main orbit has been shown **. Photons emitted on the second orbit are well separated from those of the main orbit at all beamlines. This provides the possibility of bunch separation by beamline adjustment for the timing community without significant impact on the average brightness for other users. Simulations based on linear optics from closed orbits (LOCO) and on nonlinear optics derived from the measured chromaticity and tune shift with action (TSWA) predict this separation well. Friendly user experiments in 2018 confirmed these results. The scheduled upgrade BESSY VSR *** features simultaneously stored long and short bunches. Then TRIBs optics would in principle enable the separation of the different bunches at every beamline offering unique possibilities to our users. Simulations and measurements aiming to investigate further possible optimization of the TRIBs optics are presented. * F. Armborst, P. Goslawski et al, DOI: 10.18429/JACoW-IPAC2018-TUPML052 ** P. Goslawski, F. Armborst et al. DOI: 10.18429/JACoW-IPAC2017-WEPIK057 *** A. Jankowiak et al., DOI: 10.5442/R0001 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW013 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW014 | Characterization and Implementation of the Cryogenic Permanent Magnet Undulator CPMU17 at Bessy II | 1415 |
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| In fall 2018, the cryogenic undulator CPMU17 was installed in BESSY II. Before installation, the undulator was characterized with an in-vacuum Hallprobe bench and an in-vacuum moving wire. Both systems were developed at HZB. The commissioning of the device included the orbit and tune corrections, optimization of the injection, characterization of the heat dissipation, tuning the Landau cavities for a reduction of the heat dissipation in the taper sections (temperatures below 60°C) and testing of the machine protection system. The undulator is ready to deliver light for beamline commissioning. Spectral tuning on a high undulator harmonic (longitudinal taper and alignment of e-beam orbit and undulator axis) will be done as soon as the DCM is operational. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW014 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW015 | Petra III Operation and Studies 2018 | 1419 |
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| At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. This paper describes the operational schedule, the operational statistics and the most important beam studies done at PETRA III in 2018. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW015 | |
| About • | paper received ※ 26 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW016 | New Operation Regimes at the Storage Ring KARA at KIT | 1422 |
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| The storage ring Karlsruhe Research Accelerator (KARA) at KIT operates in a wide energy range from 0.5 to 2.5 GeV. Initially, the ring was designed to serve as a Light Source for synchrotron radiation facility ANKA. Since then different operation modes have been implemented at KARA: in particular, the double bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, and different versions of low compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low alpha optics have been tested and implemented in a wide operational range of the ring and are now routinely used at 1.3 GeV for studies of CSR-induced beam dynamics and THz bursting in the micro-bunching instability. Different non-linear effects, in particular, residual high order components of magnetic fields generated in insertion devices have been studied and cured. A new operation mode at high vertical tune implemented at KARA essentially improves beam performance during user operation as well as at low alpha regimes. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW016 | |
| About • | paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW017 | Superconducting Undulator Coils with Period Length Doubling | 1426 |
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Funding: Work supported by the German government in the BMBF-project Superconducting ’Insertion Device Technologies for Ultra-Low-Emittance Light Sources’ (05K12CK1) Only since few years it has been demonstrated experimentally that NbTi based superconducting undulators (SCUs) have a higher peak field on axis for the same gap and period length in operation with electron beam with respect to permanent magnet undulators (even the ones in vacuum and cooled to cryogenic temperatures). Another advantage of NbTi based SCUs with respect to permanent magnet devices is radiation hardness, widely demonstrated for NbTi magnets, which is and will become an increasingly important issue with the small gaps in the newest machines as round beam storage rings and FELs. Moreover, SCU technology allows switching of the period length by changing the current direction in one of separately powered subset of winding packages of the superconducting coils. This feature further broadens the energy range of the emitted photons, required by the different beamlines. To this end 0.5 m long superconducting undulator coils with switchable period length between 17 mm and 34 mm have been developed. In this contribution we describe the design and report on the quench tests, as well as on the magnetic field measurements. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW017 | |
| About • | paper received ※ 25 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW018 | PETRA IV Study with Non-Interleaved Sextupole Scheme | 1430 |
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| This study is an attempt to design PETRA IV storage ring, which is an upgrade from PETRA III toward diffraction-limit synchrotron light source, based on the non-interleaved sextupole scheme. The lattice is constructed by mixing different types of cells. There are two basic building blocks. The double minus identity (DMI) cell dedicated for the chromaticity correction with non-interleaved sextupoles is tightly built up, while the combined function FODO cell with dispersion suppressors provides straights with small beta functions ideally for undulators. In addition, the hybrid section including a 10-m long super insertion device (ID) is custom-made to adapt to DESY’s current site plan. The beam dynamic behaviors are simulated and discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW018 | |
| About • | paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW019 | Progress of the BESSY VSR Cold String Development and Testing | 1434 |
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| The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW019 | |
| About • | paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW020 | Non-Linear Features of the cSTART Project | 1437 |
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| The compact storage ring for accelerator research and technology (cSTART) is being designed and will be realized at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT). One important goal of the project is to demonstrate injection and storage of a laser wakefield accelerator (LWFA) beam in a storage ring. As a first stage the compact linear accelerator FLUTE will serve as an injector of 50 MeV bunches to test the ring’s performance. A highly non-linear lattice of DBA-FDF type was studied extensively. The specific features of ring optics are reported. A special transfer line from FLUTE to cSTART including bunch compressor and non-linear elements is presented that maintains the ultra-short bunch length of FLUTE. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW020 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW021 | An Accelerator Toolbox (AT) Utility for Simulating the Commissioning of Storage-Rings | 1441 |
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| We present the development of an AT-based toolkit, which allows for realistic commissioning simulations of storage ring light sources by taking into account a multitude of error sources as well as diligently treating beam diagnostic limitations. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW021 | |
| About • | paper received ※ 08 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW022 | Commissioning Simulation Study for the Accumulator Ring of the Advanced Light Source Upgrade | 1445 |
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| The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited soft x-rays light source requires the construction of an Accumulator Ring (AR) to enable swap-out, on-axis injection. The AR lattice is a Triple-Bend-Achromat lattice similar to that of the current ALS but to minimize the magnet sizes the vacuum chamber will be significantly narrower hence requiring a careful evaluation of the magnets’ field quality. This work presents the results of a detailed error tolerance study including a complete simulation of the commissioning process. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW022 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW023 | Incorporation of a MESA Linac Modules into BERLinPro | 1449 |
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Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin, grants of the Helmholtz Association and grants of Helmholtz Association and the DFG within GRK 2128 BERLinPro is an Energy Recovery Linac (ERL) project, currently being set up at the Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany. BERLinPro is designed as - and for - experiments in accelerator physics and as a test bed for novel ERL components. MESA is an ERL project under construction at the Johannes Gutenberg-Universität, Mainz, Germany. MESA is designed as a user facility to perform experiments in dark matter physics and precision measurements of natural constants. Despite the diverse goals, the main linac, providing the larger part of the particles energy, is fairly compatible. It is planned to test and run the MESA linac module in BERLinPro, prior to its usage in MESA. The goals and benefits of this unique cooperation for both projects are outlined in this paper. The necessary adaptions in BERLinPro, including hardware aspects, the new optics, and the scope of performance are described. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW023 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW024 | Pulse Shaping Methods for Laser-Induced Generation of THz Radiation at the Delta Storage Ring | 1453 |
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| At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches to give rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW024 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW025 | The DELTA Short-Pulse Source: Upgrade Plans from CHG to EEHG | 1457 |
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| At the synchrotron light source DELTA operated by the TU Dortmund University, coherent harmonic generation (CHG) is employed to provide ultrashort pulses in the vacuum ultraviolet and terahertz (THz) regime. Here, a modulation of the electron energy induced by an interaction of an ultrashort laser pulse with an electron bunch is transformed into a density modulation by a magnetic chicane. This results in coherent emission at harmonics of the laser wavelength as well as THz radiation. With the planned upgrade towards echo-enabled harmonic generation (EEHG), much higher harmonics can be achieved by adding a second laser-electron interaction. The necessary major modifications of the DELTA storage ring and investigations of the laser-electron interaction will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW025 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW028 | Low Energy Beam Transport System for MESA | 1461 |
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| An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. The present setup includes the chopper- and bunching system. The devices are of most importance in order to achieve sufficient bunch compression particularely at higher bunch charges and currents. With the circular deflecting cavity of the chopper system it is possible to measure the longitudinal dimension of the bunches upstream of the buncher whereas downstream the longitudinal size will be measured by Smith Purcell radiation. Based on experimental results obtained from this setup we will discuss the beam parameter and compare them with simulations of the beamline. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW028 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW029 | The Injection System and the Injector Complex for PETRA IV | 1465 |
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| PETRA IV project is to upgrade PETRA III to a synchrotron radiation source with an ultra-low emittance. Due to the small dynamic aperture of the PETRA IV storage ring, a horizontal on-axis injection is prepared. In this paper, the preliminary study of the injection scheme is described. To meet the requirements of the on-axis injection, a plan of a new injector complex, including the Gun, the LINAC and the accumulator is shown in this paper. Several options are discussed in this paper, too. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW029 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW031 | Elettra, Present and Future | 1468 |
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| The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with the final version of the upcoming upgrade, the diffraction limited light source Elettra 2.0. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW031 | |
| About • | paper received ※ 16 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW032 | Mode-Locked Pulse Oscillation of a Self-Resonating Enhancement Optical Cavity | 1471 |
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| A power enhancement optical cavity is a compelling means of realizing a pulsed laser with a high peak power and high repetition frequency, which is not feasible using a simple amplifier scheme. However, a precise feedback system is necessary for maintaining the narrow resonance condition of the optical cavity; this has become a major technical issue in developing such cavities. We have developed a new approach that does not require any active feedback system, by placing the cavity in the outer loop of a laser amplifier. We report on the first demonstra-tion of a mode-locked pulse oscillation using the new system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW032 | |
| About • | paper received ※ 15 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW033 | Status of Test-Accelerator as Coherent THz Source (t-ACTS) at ELPH, Tohoku University | 1475 |
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| A test-Accelerator as Coherent Terahertz Source (t-ACTS) has been under development at the Research Center for Electron Photon Science (ELPH), Tohoku University, in which an intense coherent terahertz radiation is generated from the femtosecond electron pulses. Velocity bunching scheme in a traveling accelerating structure is employed to generate femtosecond electron pulses, and the generation of femtosecond electron pulses was confirmed by spectrum analysis of coherent transition radiation using Michelson interferometer. Coherent transition radiation and coherent undulator radiation in the terahertz (THz) region from the short electron pulses has been demonstrated, and their characteristics such as frequency spectrum, spatial distribution and polarization were measured and compared with theoretical calculations. We have succeeded to generate the coherent transition radiation up to approximately 5 THz and the coherent undulator radiation with narrow bandwidth from 2.6 to 3.4 THz. At present, development of a variable polarized THz light source using a crossed-undulator system is being carried out. In addition, we are developing a nondestructive beam monitor using Cherenkov radiation emitted from the electron pulses. The status of t-ACTS will be presented in this conference. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW033 | |
| About • | paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW035 | A Highly Brilliant Compact 3 GeV Light Source Project in Japan | 1478 |
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| A highly brilliant compact 3 GeV light source project was proposed in Japan. The light source would be constructed in Sendai, north-east part of Japan. It provides brilliant soft X-ray beam to widely cover wavelengths ranging from EUV to hard X-ray in Japan together with SPring-8. The accelerator system is now mostly designed except for several linac components and so on. We have chosen a 4-bend achromat lattice to achieve a low emittance keeping a small circumference with a rather relaxed space issue. The number of cells is 16 and the ring circumference is about 350 m. Number of available beam lines are 26 including short straight sections for multi-pole wigglers. Horizontal emittance is expected to be around 1.1 nmrad, and the maximum brilliance may exceed 1021 at 1 - 3 keV region with a stored current of 400 mA. The designs of many components such as vacuum chambers, magnets and monitors are employed from those studied for SPring-8 upgrade project. A full energy injector linac equipped with a thermionic gun and C-band accelerating structures is employed to produce sufficiently low emittance beams for efficient beam injections. The C-band system is adopted from those developed for XFEL SACLA with some modifications. In the future, the injector would be upgraded as an electron driver for SXFEL. Details of the project and accelerator system will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW035 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW036 | 1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance | 1482 |
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A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %.
* S. Sakanaka, et.al., Nucl. Instr. and Meth. A 877 (2017)197, https://doi.org/10.1016/j.nima.2017.08.051 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW036 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW037 | Systematic Measurements of the Coherent THz Spectra by Magnetic Bunch Compression at the Compact ERL | 1486 |
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| Short electron bunch beam is one of the key elements of a Free Electron Laser (FEL) or intense THz coherent light source. The Energy Recovery Linac (ERL) has the strong advantage of operation of such an electron bunch at high repetition rate and is expected to increase the photon flux. At the Compact ERL in KEK site, we have demonstrated the magnetic bunch compression at the 180-degree return arc and measured the THz spectra of the Coherent Transition Radiation (CTR). This paper reports the revamped THz beamline and the improvement of the beam tuning as well as the systematic measurements of the THz spectra by magnetic bunch compression. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW037 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW038 | Study on Coherent THz Radiation Using Tilt Control of Electron Beam | 1489 |
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Funding: This work was supported by a research granted from JSPS KAKENHI 17H02821. The terahertz wave is located in the intermediate frequency band between radio waves and light waves, and researches on the light sources such as terahertz quantum cascade laser and femtosecond laser based THz sources are being conducted*. As a new terahertz light source, we are studying coherent Cherenkov radiation by using the tilt control of electron beam and irradiating the target medium. Since the radiation intensity of Cherenkov radiation depends on the target medium, comparison of three kinds of medium with different refractive index and density, and optimization of the target shape were performed. In addition, we are going to try quasi monochromatization of radiation by using multi slit to control the form factor of the electron beam. In this presentation, we will report the experimental results of target optimization and quasi monochromatization and the future prospects. *S. S. Dhillon, et al., The 2017 terahertz science and technology roadmap, J. Phys. D: Appl. Phys., 50 (2017) 043001. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW038 | |
| About • | paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW039 | Error Study and Correction of Hefei Advanced Light Source | 1492 |
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| Hefei Advanced Light Source (HALS) is a future diffraction limited storage ring. The machine performance under all kinds of magnet errors is a vital component in physical design. In this paper, we present our work on the closed orbit correction, the linear beam optics compensation and the coupling control in HALS. After correction, the dynamical aperture can suffice the injection scheme. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW039 | |
| About • | paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW040 | Study of Seven-Bend Achromat Lattices with Interleaved Dispersion Bumps for HALS | 1495 |
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| Previously, we proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleav-ed dispersion bumps, which was then used to design a 7BA lattice for the Hefei Advanced Light Source (HALS) storage ring. Recently, such a 7BA lattice was further designed and optimized for the HALS by changing the number of lattice cells, scanning working point and employing octupoles. And two new HALS designs with such 7BA lattices have been made, one with 30 lattice cells and a natural emittance of 25 pm·rad and the other with 28 cells and 33 pm·rad. They had much better nonlinear dynamics perfor-mances than the previous design. The detailed study for these two HALS lattices will be presented in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW040 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW041 | Super-Period Locally Symmetric Lattices for Designing Diffraction-Limited Storage Rings | 1498 |
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| To achieve better nonlinear dynamics performance for a diffraction-limited storage ring, previously we proposed a locally symmetric multi-bend-achromat (MBA) lattice concept, where beta functions are locally symmetric about two mirror planes of each lattice cell. To have both high-beta long straight sections for beam injection and low-beta ones for higher brightness of insertion device radiation, many storage ring light sources use super-period lattices. The locally symmetric MBA lattice can be naturally extended to the super-period case. In the super-period locally symmetric (SP-LS) lattice, many nonlinear dynamics effects can be effectively cancelled out within one super-period lattice cell, and also there are many knobs to be used for further nonlinear optimization. As examples, two SP-LS lattices have been designed towards diffraction-limited emittances. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW041 | |
| About • | paper received ※ 20 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW042 | Study of the Intra-beam Scattering Effects in the HALS Storage Ring | 1501 |
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Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077). The Hefei Advanced Light Source (HALS) is designed to be a dedicated 4th generation diffraction limited light source. In 2018, the baseline lattice of the HALS storage ring has been proposed, with an ultra-low natural emittance of about 25 pm-rad. The preliminary study of intra-beam scattering effects on the beam emittance growth in the HALS storage ring has been performed with this baseline lattice. Due to the limited synchrotron radiation in this storage ring, damping wigglers are expected in this storage ring to reduce the damping time and reduce the emittance. In this paper, we will present the simulation results of the IBS effects, estimated effectiveness of damping wiggler and the corresponding linear optics calibration of the perturbation due to insertion device, and finally the estimated Touschek lifetime will be shown. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW042 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW043 | Simulation of Model Independent Analysis to HEPS Storage Ring | 1504 |
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| Model Independent Analysis (MIA) is a beam analysis method applied for Turn-by-Turn (TBT) Beam Position Monitor (BPM) data. To develop the commissioning method of the HEPS storage ring, we simulate application of MIA on HEPS storage error model to measure and cor-rect the optics parameters. Difficulties and limitations of the MIA method are also discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW043 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW045 | Lattice Design for the Reversible SSMB | 1507 |
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| Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW046 | Progress of Lattice Design and Physics Studies on the High Energy Photon Source | 1510 |
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| The High Energy Photon Source (HEPS) is an ul-tralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physics design and related studies of HEPS over the past year, covering issues in storage ring lattice design, injection and injector design, insertion device effects, error study and lattice calibration, collective effects, etc. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW046 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW048 | Simulation of Injection Efficiency for the High Energy Photon Source | 1514 |
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Funding: Work supported by Natural Science Foundation of China (No.11605212). A ’high-energy accumulation’ scheme [1] was proposed to deliver the full charge bunches for the swap-out injec- tion of the High Energy Photon Source. In this scheme, the depleted storage ring bunches are recovered via merging with small charge bunches in the booster, before being refilled into the storage ring. In particular, the high charge bunches are transferred twice between the storage ring and the booster, and thus it is essential to maintain a near per- fect transmission efficiency in the whole process. In this paper, major error effects affecting the transmission efficiency are analyzed and their tolerances are summarized, injection simulations indicate a satisfactory transmission efficiency is achievable for the present baseline lattice. * Z. Duan, et al., "The swap-out injection scheme for the High Energy Photon Source", Proc. IPAC’18, THPMF052 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW048 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW051 | Generation of Two Terahertz Radiation Pulses with Continuously Tunable Frequency and Time Delay | 1518 |
| SUSPFO072 | use link to see paper's listing under its alternate paper code | |
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| We propose to generate two narrow band terahertz pulses radiated from two temporally modulated relativistic electron beams, which are generated in a photo-injector. The temporal profile of the drive laser is modulated by means of the paired chirped pulses beating technique, leading to the generation of two pre-bunched electron beams. Coherent transient radiation (CTR) is considered as the mechanism for terahertz radiation generation. The frequencies of the two terahertz pulses can be independently tuned by adjusting the paired beating frequencies, and the interval between the two terahertz pulses can be adjusted by the optical delay line. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW051 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW052 | STUDY OF THE RAMPING PROCESS FOR HEPS BOOSTER | 1521 |
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| The High Energy Photon Source (HEPS) is a 6-GeV, ul-tralow-emittance storage ring light source to be built in Huairou District, Beijing, China. The beam energy ramps from 500 MeV to 6 GeV in 400 ms, during which the RF voltage increases accordingly to keep the momentum acceptance large enough. The booster is designed to operate at 1 Hz repetition frequency. In this paper the energy ramping curve, RF choice, beam parameters changing curves and eddy current effect in HEPS booster will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW052 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW053 | Simulations of the Injection Transient Instabilities for the High Energy Photon Source | 1524 |
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Funding: Work supported by Natural Science Foundation of China (No.11605212). A "charge recovery in booster" scheme* was proposed to deliver the full charge bunches for the swap-out injection of the High Energy Photon Source. In this scheme, the booster is employed also as a full energy accumulator ring to capture the high charge bunch extracted from the storage ring via merging with the small charge bunch accelerated in the booster, after enough damping in the booster for about 20 ms, the recovered full charge bunch is re-injected into the storage ring. This scheme avoids the challenges to accelerate a bunch charge of ~ 15 nC, and is cost effective compared to building a dedicated 6 GeV accumulator ring. However, there will be a period of time during injection that one bunch is missing in the storage ring, which inevitably introduces some injection transients. Since "transparency" to the user experiments is a desired feature of injection schemes for next generation diffraction-limited storage rings, the injection transient effects are simulated for the proposed injection scheme, and how it would affect the user experiments are carefully evaluated. * Z. Duan, et al., "The swap-out injection scheme for the High Energy Photon Source", Proc. IPAC’18, THPMF052 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW053 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW054 | Design of a Hybrid Seven-Bend-Achromat Lattice for a High-Energy Diffraction-Limited Storage Ring Using a New Optimization Method | 1528 |
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| Recently, we proposed a new optimization method, with nonlinear dynamics indicators considered in the linear optics design, for designing hybrid multi-bend-achromat (MBA) lattices. With this method, two hybrid MBA lattices for medium-low-energy diffraction limited storage rings (DLSRs) have been designed, showing remarkable effectiveness in improving nonlinear dynamic performance. In this paper, we will apply this optimization method to the design of a hybrid 7BA lattice for a 6 GeV DLSR with the same circumference as that of HEPS. In the design, the strengths and arrangement of magnets of this lattice also meet the engineering requirement for HEPS. The designed lattice has a natural emittance of 34 pm·rad. The nonlinear dynamic performance is satisfactory, with a dynamic aperture of about 6 mm and 3 mm in the horizontal and vertical directions, respectively, and a dynamic momentum aperture of larger than 5%, which also shows the power of our optimization method. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW054 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW055 | Comparison of Optimization Methods for Hybrid Seven-Bend-Achromat Lattice Design | 1532 |
| SUSPFO079 | use link to see paper's listing under its alternate paper code | |
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| Generally, for a hybrid multi-bend-achromat (MBA) lattice with fixed linear optics, there is little potential to further optimize the nonlinear dynamics due to limited free knobs. To obtain a hybrid MBA lattice with better nonlinear dynamics performance, it is better to consider some indicators of nonlinear dynamics as objective functions in designing the linear optics using an optimization algorithm. In this paper, integral strengths of sextupoles and natural chromaticities are used as the nonlinear dynamics indicators, and different optimization methods with both or either of the two indicators are carried out and compared. As an example, a hybrid 7BA lattice with an energy of 2.4 GeV is designed towards an emittance of less than 70 pm·rad. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW055 | |
| About • | paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW056 | Comparison of Constrained Optimization Methods for Designing a Multi-Bend Achromat Lattice | 1535 |
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| In the design of a multi-bend achromat (MBA) lattice for a diffraction-limited storage ring, there are usually many magnet parameters to be optimized and some stringent constraints to be satisfied. For example, to cancel out nonlinear dynamics effects, the phase advances between some sections are generally required to be set to certain values in the lattice design. For better designing a MBA lattice using an evolutionary algorithm, the handling of constraints will be important, because it is very hard to satisfy the constraints for most or even all of solutions in the early generations of the algorithm. This paper will first describe some methods for handling constraints, which are then applied to designing a hybrid 7BA lattice. The comparison of these methods shows that better lattice solutions can be obtained by including constraints into objective functions. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW056 | |
| About • | paper received ※ 23 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW057 | A Ten-Bend Achromat Lattice with Interleaved Dispersion Bumps for a Diffraction-Limited Storage Ring | 1538 |
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| Recently, a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps (IDB-MBA), was proposed to design the HALS storage ring, which presented better performance of both on- and off-momentum nonlinear dynamics. Since the beam emittance scales inversely with the third power of the number of bending magnets, in this paper we will study a new IDB-MBA lattice with more bending magnets. It is feasible to satisfy the requirement of the IDB-MBA concept in a 10BA lattice, and an IDB-10BA lattice is then designed for a storage ring light source with an energy of 2.4 GeV. The designed lattice has an ultra-low natural emittance of 81 pm·rad, and a dynamic aperture of about 6 mm and a large dynamic momentum aperture of 6% are achieved. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW057 | |
| About • | paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW059 | Studies of The Electron Beam Lifetime in Solaris Electron Storage Ring | 1541 |
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| Solaris storage ring is a recently constructed and commissioned machine operated in decay mode. With total accumulated beam dose near to 1000 A.h the measured total lifetime has reached 16 h for 270mA of a stored current. In this paper, the beam lifetime studies are presented using measured residual gas analysis and vertical scraper position for tuned and detuned Landau cavities. It shows that for stable beam the lifetime is dominated by the interaction of the electron with residual gas (vacuum lifetime) and between electrons interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from theoretical analysis are also compared with the measured beam lifetime. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW059 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW061 | First Study for an Upgrade of the ALBA Lattice | 1544 |
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| ALBA has started a study that will produce the design of a new lattice for a diffraction limited photon source. The baseline lattice should preserve the present circumference and energy, and keep the insertion device beamline source points as much as possible unchanged. The first solution is a 16-fold periodic ring based on a 7BA cell with dispersion bump, paired sextupoles and anti-bends. An emittance of 155 pm·rad would be reached without longitudinal gradient in the dipole magnets. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW061 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW063 | Studying the Dynamic Influence on the Stored Beam From a Coating in a Multipole Injection Kicker | 1547 |
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| The MAX IV 3 GeV ring is the first synchrotron light source utilizing the Multi-Bend Achromat scheme to achieve a low horizontal bare-lattice emittance of 328 pm rad providing high brilliance x-rays for users. A novel Multipole Injection Kicker (MIK) designed and constructed by SOLEIL is used to allow top-up operation with only minor disturbances to the stored beam, i.e., the users. We investigate the stored beam perturbations due to quadrupole fields arising during the MIK pulse, originating from its inner coating. Maximum bunch emittance growth of §I{21}{πco\meter\radian} was found in simulations. Measurements of the stored beam impact are performed and found to be in good agreement with simulations. We conclude that the MIK at MAX IV 3 GeV has the potential to deliver quasi-transparent injections with good capture efficiency. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW063 | |
| About • | paper received ※ 06 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW064 | Trials of Beam-Based Sextupole Calibration through 2nd Order Dispersion | 1551 |
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| In order to achieve nominal performance in terms of the dynamic aperture and lifetime of a storage ring, it is important to be able to characterise and correct its second order optics. At the MAX IV 3 GeV storage ring in Lund, Sweden, the linearity of the 2nd order dispersion with chromatic sextupole field strengths has been utilised to investigate the sextupole circuits. The beating induced in the 2nd order dispersion when reducing the strength of a sextupole magnet can be compared to the beating in simulations. From this a beam-based sextupole calibration curve can be found. This work was inspired by similar work done at ESRF. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW064 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW066 | Exploring the Potential of the Swiss Light Source | 1554 |
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| Swiss Light Source (SLS) has been on-line since 2001. Although its performance meets the specifications, it still has a potential to achieve better storage ring beam parameters. We explore two possible improvements. The first one is for the beam lifetime. There are 480 rf buckets while normally 390 bunches are stored. The gap in filing pattern (90 empty buckets) is held to suppress ion instability. After many years of operation, however, the vacuum condition is much better than that of the time when the SLS was turned on. Hence it is possible to shorten the gap. The beam lifetime can then be prolonged due to less bunch current while keeping the net beam current. The study may be also useful to predict possible filling patter in SLS2, which is the SLS upgrade planned. The second one is for the beam emittance. The nominal energy closed orbit coincides with the axes of quadrupole magnets. An off-momentum closed orbit is therefore off-centered through quadrupoles, resulting in a damping partition shift. The beam emittance can be decreased at the expense of a larger energy spread. This was successfully achieved in the ESRF booster. We study whether it is applicable to the SLS storage ring. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW066 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW068 | New Source for Bending Magnet Beam Lines at Ultra-Low-Emittance Ring | 1557 |
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| The Iranian Light Source Facility (ILSF) is a 3 GeV 3rd synchrotron radiation laboratory in the basic design phase. The Storage Ring (SR) is based on a five-bend achromat (5BA) lattice providing low horizontal emittance of 0.27 nm.rad. Due to the ILSF storage ring, straight section limits the use of the short length wigglers for hard X-ray generation is recommended. Which are removable in the lattice. In this article, the new design of the 3-pole wiggler is investigated and the main parameters of this 3-pole wiggler, by considering the ILSF storage ring characteristics, is modified. Also, the effect of the new 3-pole wiggler on the beam dynamics is investigated and the advantages of the new design are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW068 | |
| About • | paper received ※ 28 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW069 | Insertion Devices for the Day-One Beamlines of ILSF | 1561 |
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| The Iranian Light Source Facility (ILSF) is a new 3 GeV synchrotron radiation laboratory with ultralow emittance of 270 pm-rad, which is in the design stage. Seven beamlines are planned to start operation with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The most operational undulator for polarized radiations -Apple II- has been deliberated for the solid state electron spectroscopy, the Spectromicroscopy and the ARPES beamlines. The hybrid wigglers for the XPD and the EXAFS beamlines and in-vacuum undulators for Macromolecular Crystallography and SCD beamlines have been chosen too. The emission of these IDs covers a wide spectral range extending from hard X-rays to UV. Pre-design of the IDs were already done in ILSF. The main parameters of magnetic design as well as radiation parameters for the first phase of ILSF insertion devices have been described in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW069 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW070 | Multi-Bend Achromat Lattice Design for the Future of TPS Upgrade | 1564 |
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| We present a TPS upgrade option with the hybrid 7BA (H7BA) lattice. We also derive a simple formula on optimal dipole angle distribution among H7BA dipoles. The agreement is satisfactory. We also report preliminary results on the dynamic aperture (DA) optimization. Possible improvement on H7BA lattice is outlined. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW070 | |
| About • | paper received ※ 24 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW071 | Optimization and Measurements on the Double Mini-Betay Lattice in the TPS Storage Ring | 1567 |
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| The Taiwan Photon Source (TPS) is capable of operat-ing in multi-bunch and single-bunch mode. To operate in a hybrid mode as requested by users, we developed a lattice with chromaticities of 0.8/2 (x/y) to provide higher single bunch currents. Beam dynamics simulations and lattice characterizations including dynamic aperture, frequency map analysis, tune shift with energy, tune shift with amplitude, and betatron coupling will be discussed in this report. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW071 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW072 | Design and Optimization of Full Energy Injector Linac for Siam Photon Source II | 1570 |
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| The new Thailand synchrotron light source, Siam Photon Source II (SPS-II), has been designed based on a 3 GeV storage ring with a Double-Triple Bend Achromat (DTBA) lattice and a full energy injector linac. The linac consists of an S-band photocathode RF gun, C-band accelerating structures and two magnetic chicanes. In addition to its main function as the storage ring injector, the linac is capable of producing sub-picosecond electron bunches for additional short-pulse beamlines at the end of the linac. The linac also has a potential to become a driver of a soft X-ray Free Electron Laser (FEL) operating adjacent to the storage ring. In this paper, start-to-end simulations of the full energy linac are presented. Optimization was performed in order to fulfil requirements for both storage ring injection and short pulse generation. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW072 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW075 | Towards a Diffraction Limited Storage Ring | 1573 |
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| A Lattice for a 500 m circ. Tunnel, based on First Principles & Best Practices is presented. Background: MAX-IV has made a "quantum leap" towards a Diffraction Limited Storage Ring (DLSR) by an Engineering-Science, i.e., Systems, Approach; leading to a Paradigm Shift(s): e.g. the Magnet Reference Radius is a Key Parameter, a Design Choice, that must be considered at an early stage for Robust Design. In addition, the pursuit of Systematic Benchmarks, MAX-I -> MAX-IV, has enabled the pursuit of Disruptive Technologies with Predictable Results. For example: Combined-Function Magnets (built-to-print) enabling an "IKEA Approach" (innovative, prompted by low-budget) like the use of Concrete Girders, Vacuum Requirements mitigated by NEG Coating, and Solid State Modulators providing a Reliable Injector by a Full-Energy Linac. Since "The Experiment" now has been done, Permanent Magnets, well understood for high-end Insertion Devices, provides another opportunity/step for a Next Generation. Besides, the Electricity Bill for Conventional Magnets is a significant part of the Operations Cost. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW075 | |
| About • | paper received ※ 20 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW076 | Early Commissioning Simulation of the Diamond Storage Ring Upgrade | 1577 |
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| A low beam emittance lattice has been designed for up-grade of the Diamond storage ring. Due to the use of strong focusing elements and rather small vacuum cham-ber and considering the required short dark time, commis-sioning of the designed storage ring becomes very chal-lenging. This paper briefly explains the progress of early commissioning simulations of the storage ring, gives the required engineering tolerances, presents the first simula-tion results and discusses the non-linear beam dynamics (NLBD) issues after successful commissioning with and without insertion devices (IDs). | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW076 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW077 | Impact of the DIAD Wiggler and ’Missing-sextupole’ Optics on the Diamond Storage Ring | 1581 |
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In order to generate space for a short, out-of-vacuum multipole wiggler for the DIAD beamline, a single sextupole was removed from one of the DBA arcs in the Diamond Storage Ring during June 2018. The removal of this sextupole presented a number of challenges to the operation of the storage ring, requiring a re-optimisation of the remaining sextupole strengths*, a change in tune-point and modification of the orbit and coupling correction schemes. In this paper we describe the implementation of these changes, and provide an assessment of the impact that the installed wiggler has made on the storage ring parameters.
* B. Singh et al. ’Studies to Install a Multipole Wiggler by Removing a Chromatic Sextupole in Diamond Storage Ring’, Proc. IPAC 2016, Busan, Korea, paper THPMR050, (2016) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW077 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW078 | Harmonic Cavity Design Choice for Lifetime Increase in Diamond-II | 1585 |
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| The ongoing trend towards synchrotron light storage rings with ultralow emittance leads to a requirement for strong magnet gradients, which reduce the dynamic aperture and thus the Touschek lifetime of the machine. This is also the case for the planned upgrade of the Diamond Light Source. One option to increase the Touschek lifetime is to lengthen the electron bunches with a harmonic cavity operated close to a harmonic of the fundamental RF frequency. This paper presents studies of a harmonic cavity for Diamond-II with the focus on maximising the lifetime increase. It is foreseen that the ring will have to operate with a gap in the fill pattern to avoid instabilities and therefore multiparticle tracking was used to determine the effect on stability and lifetime for various cavity parameters taking into account transient beam loading. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW078 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW079 | Exploratory Lattice Design Studies for Diamond-II | 1589 |
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| We pursue Robust Design of a Ring-Based Synchrotron Light Source as a System. In particular, the Design Phi-losophy is based on: ’ To Control the Nonlinear Dynamics: Control the Linear Optics. In particular, by: ’ Optimal Control of Natural Chromaticity. ’ ’-I Transformer’ between Chromatic Sextupoles for Unit Cell. ’ Higher-Order-Achromat for Super Period. In addition, by pushing the Requirements for Robust & Efficient Injection ’Upstream’, i.e., by considering On-Axis Injection, and by utilizing Reverse Bends (to trans-cend the reductionist Theoretical Minimum Emittance Cell), either: ’ the Natural Emittance can be reduced further, ’ or the Touschek Lifetime can be improved. Bottom line, a Design Choice. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW079 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW080 | Alternative Lattice Design for Diamond-II | 1593 |
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| Plans for upgrade of the Diamond Light Source aim to reduce beam emittance by a factor of 20 or better. This is motivated by demand for photon flux with significantly high brightness and transverse coherence. The baseline lattice design for the Diamond-II upgrade has been recently proposed, however alternative design are under investigation to reduce the emittance even further. This paper presents a new lattice design based on implementation of bending magnets with transverse field gradient only. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW080 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW082 | Impedance of the Flange Joints With the RF Contact Spring in NSLS-II | 1597 |
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Funding: This work was supported by Department of Energy Contract No. DE-SC0012704 Since the beginning of the NSLS-II commissioning, temperature of the vacuum components has been moni-tored by the Resistance Temperature Detectors located predominantly outside of the vacuum enclosure and at-tached to the chamber body. Temperature map helps us to control overheating of the vacuum components around the ring especially during the current ramp-up. The average current of 475mA has been achieved with two main 500MHz RF cavities and w/o harmonic cavities. Effect of the RF shielded flanges on local heat and on the longitu-dinal beam dynamics is discussed in details. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW082 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW084 | Multi-pass ERL in a ’Dogbone’ Topology | 1601 |
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Funding: Work has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy. The main thrust of a multi-pass RLA is its very efficient usage of expensive linac structures. That efficiency can be further enhanced by configuring an RLA in a ’dogbone’ topology, which further boosts the RF efficiency by factor of two (compare to a corresponding racetrack). However, the ’dogbone’ configuration requires the beam to traverse the linac in both directions, while being accelerated. This can be facilitated by a special ’bisected’ linac Optics. Here, the quadrupole gradients scale up with momentum to maintain periodic FODO structure for the lowest energy pass in the first half of the linac and then the quadrupole strengths are mirror reflected in the second linac half. The virtue of this optics is the appearance of distinct nodes in the beta beat-wave at the ends of each pass (where the droplet arcs begin), which limits the growth of initial betas at the beginning of each subsequent droplet arc. Furthermore, ‘bisected’ linac optics naturally supports energy recovery in the ’dogbone’ topology. In this paper, we present a-proof-of-principle lattice design of a multi-pass ’dogbone’ ERL. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW084 | |
| About • | paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW085 | A Hard X-Ray Compact Compton Source at CBETA | 1604 |
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| Compton backscattering at energy recovery linacs (ERLs) promises high flux, high energy x-ray sources in the future, made possible by high quality, high repetition rate electron beams produced by ERLs. CBETA, the Cornell-BNL ERL Test Accelerator currently being built and commissioned at Cornell, is an SRF multi-turn ERL using Non-Scaling Fixed Field Alternating-gradient (NS-FFA) arcs. CBETA has high quality design parameters with an anticipated top energy of 150 MeV on the fourth pass. The expected parameters of a Compton source at CBETA include a top x-ray energy of over 400 keV with a flux on the order of 1012 ph/s. In this paper, we present anticipated parameters and potential applications in science and engineering for this source. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW085 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW086 | Energy and RF Cavity Phase Symmetry Enforcement in Multi-Turn ERL Models | 1606 |
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| In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration, and the beam should achieve specific energy targets during each loop that returns it to the linac. For full energy recovery, and for every returning beam to meet loop energy requirements, we must optimize the phase and voltage of cavity fields in addition to selecting adequate flight times. If we impose symmetry in time and energy during acceleration and deceleration, fewer parameters are needed, simplifying the optimization. As an example, we present symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) with solutions that satisfy the optimization targets of loop energy and zero cavity loading. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW086 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW088 | Removal and Installation Planning for the Advanced Light Source - Upgrade Project | 1609 |
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| The ALS-U project is a proposed upgrade to the Advanced Light Source (ALS) at Berkeley Lab that aims to deliver diffraction limited performance in the soft x-ray range. By lowering the horizontal emittance to about 70 pm rad, the brightness for soft x-rays will increase two orders of magnitude compared to the current ALS. The design utilizes a nine-bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper will describe the preliminary plans for the installation of the new three-bend achromat accumulator ring (AR) in the existing tunnel and for replacing the current storage ring with the new nine-bend achromat lattice. The AR will be installed during regular maintenance shutdowns while the ALS continues to operate. The SR will be replaced during a nine months installation period followed by three months of commissioning during the twelve darktime period. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW088 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW089 | Tunable Bunch Train Generation Using Emittance Exchange Beamline With Transverse Wiggler | 1612 |
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Funding: This work is supported by LDRD program at Argonne National Laboratory and Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357. Emittance exchange beamline provides a unique correlation between the upstream transverse momentum and downstream longitudinal timing. Similar to the bunch train generation concept using energy modulation and chicane, the emittance exchange beamline can convert the transverse momentum modulation to the temporal modulation at the end of the beamline. The beam can obtain this transverse modulation from alternating magnet array (e.g. 90 degree rotated undulator). While most of other methods provide only one knob to control both micro-bunch length and bunch-to-bunch spacing or hard to control one of the knobs, this method provides separated knobs for the micro-bunch length and spacing and they are easy to control. These knobs enable to separately control the fundamental frequency of the radiation and its bandwidth. We plan to demonstrate this method at Argonne Wakefield Accelerator facility (AWA). This poster present progress on this new method and its demonstration at AWA. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW089 | |
| About • | paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW090 | Experimental Tests of the Automated APS-U Commissioning Algorithm at APS | 1615 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357 APS Upgrade (APS-U) will feature hybrid seven-bend achromat lattice with very strong focusing elements and relatively small vacuum chamber aperture. Achieving design lattice parameters during commissioning will need to be accomplished quickly in order to minimize dark time for APS users. The paper will describe the automated start-to-end lattice commissioning algorithm starting with the first-turn trajectory correction and ending with the lattice correction. It will then show simulation results of the APS-U commissioning, and finally present results of the experimental tests of the commissioning at the existing APS. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW090 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW091 | Lattice Measurements of the APS Injector Rings | 1619 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357 APS Upgrade will feature an entirely new storage ring but will keep the existing injector complex consisting of the linear accelerator, Particle Accumulator Ring (PAR) and Booster. Due to small dynamic aperture of the APS Upgrade lattice, swap-out injection is adapted when an entire old bunch is replaced with a new bunch. This injection requires Booster to provide high-charge bunches with up to 17 nC in a single bunch. An extensive work is being carried out on characterizing the existing injector rings to ensure future high-charge operation. In this paper, we will present results of the lattice measurement using the response matrix fit. We will show the analysis of the achievable lattice measurement accuracy in the APS Booster and describe fit parameter modifications required to achieve good fit accuracy for the PAR. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW091 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW092 | Working Impedance Model and Its Effect on the Intensity Limitation of Petra-IV Storage Ring | 1623 |
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| We made sufficient progress in modeling the imped-ance of the PETRA-IV storage ring. The result was ap-plied to estimate the impedance-based single and multi-bunch intensity limit. Due to the extremely small emit-tance of the beam the intrabeam scattering (IBS) effects will be significant unless they are reduced by bunch lengthening. The 3rd harmonic cavity was proposed to dilute the bunch density which resulted in the small syn-chrotron frequency with a large spread. Because of the complexity introduced by impedance and harmonic cavity we used broadband impedance up to 200 GHz to compute the parameters such as bunch length and energy spread at different currents. We found that the microwave instability started very early in current less than 0.5 mA. Even if it is small, the prediction by tracking simulation was consistent with another diffraction-limited storage ring (DLSR) when the Keil-Schnell criterion was used to predict one from the other. Then, we present the single-bunch current limit which had included the effect of geometric and resistive wall impedances of the NEG-coated chamber. Finally, we present the emittance and lifetime which can be realistically achieved in the ring with the above collective effects included. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW092 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW093 | Compensation of Insertion Device Induced Emittance Variations in Ultralow Emittance Storage Rings by a Dispersion Bump in a Wiggler | 1627 |
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Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231. Multi-bend achromat lattices allow for the design of extremely low emittance electron storage rings and hence for the realization of extremely high- brightness X-ray photon sources. In these new rings, the beam energy lost to radiation in the insertion devices (IDs) is often comparable to that lost in the ring dipole magnets. This implies that with respect to the typical 3rd generation light source, these new machines are more sensitive to the energy loss variations randomly occurring as the many users independently operate the gap of their IDs. The consequent induced variations in radiation damping time, equilibrium emittance, and transverse beam sizes at the radiation point sources can be significant and degrade the experimental performance in some of the beam-lines. In this paper we describe and discuss a possible method to compensate for such emittance variations by using a variable dispersion bump localized inside a fixed gap wiggler. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW093 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW094 | First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization | 1631 |
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Funding: This research is funded by US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231. The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW094 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW095 | Progress on a Novel 7BA Lattice for a 196-m Circumference Diffraction-Limited Soft X-Ray Storage Ring | 1635 |
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Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231. The ALS Upgrade to a diffraction-limited soft x-ray storage ring calls for ultralow emittance in a very limited circumference. In this paper we report on progress with a lattice based on a 7BA with distributed chromatic correction. This lattice relies heavily on longitudinal gradient bends and reverse bending in order to suppress the emittance, so that, despite having only seven bends, ultralow emittance can be achieved in addition to large dynamic aperture and momentum acceptance. An initial alternate 7BA lattice has been revised to relax magnet requirements as well as further increase off-energy performance and resilience to machine imperfections. We now demonstrate ±2.5 mm dynamic aperture including errors and calculate the effect of IBS to show that this lattice achieves 6 hours Touschek lifetime (at 500 mA, including errors) and a brightness of roughly 3x1021 ph/s/mm2/mrad2/0.1%BW at 1 keV. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW095 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW097 | Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source | 1639 |
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Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097 | |
| About • | paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW098 | Fabrication & Cold Tests of a Millimeter-Period RF Undulator | 1643 |
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Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515, and the National Science Foundation under Contract No. PHY-1415437. To reduce the linac energy required for an FEL radiating at a given wavelength, and hence its size, a smaller undulator period with sufficient field strength is needed. Previous work from our group successfully demonstrated a microwave undulator at 11.424GHz, using a corrugated cylindrical waveguide operating at the HE11 modes. We have designed a mm-wave undulator cavity at 91.392GHz* with an equivalent undulator period of 1.75 mm. This undulator requires 1.4 MW for sub microsecond pulses for an equivalent K value of 0.1. In this work we present the mechanical design and fabrication of this 91.392 GHz RF Undulator, as well as preliminary cold test data. * F. Toufexis and S.G. Tantawi, "A 1.75-mm Period RF-Driven Undulator", Proceedings of IPAC17. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW098 | |
| About • | paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW099 | Superconducting Crab Cavity Options for Short X-Ray Pulse Generation in SPEAR3 | 1647 |
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Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515. We are exploring methods to generate short X-ray pulses in SPEAR3 on the order of 1 ps to enable studying ultrafast processes in materials. We are developing a 2-frequency crab cavity scheme with two sets of crab cavities* at the 6th and 6.5th harmonics of the 476 MHz ring RF frequency. In previous work we studied a normal conducting crab cavity for SPEAR3**. In this work we explored two superconducting cavity options: a traditional elliptical cavity and the Quasi-waveguide Resonator***. We found that the Quasi-waveguide Resonator cannot meet our field uniformity specifications due to higher order multipole fields. We then optimized a traditional elliptical cavity with the input, Lower Order Modes, and Higher Order Modes couplers following the Argonne Advanced Photon Source design. * A. Zholents, et al, Nucl. Instrum. Methods Phys. Res., Sect. A, Vol. 425 (1999), p. 385. ** Z. Li, et al, Proceedings of IPAC17. *** A. Lunin, et al, Proceedings of HOMSC14. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW099 | |
| About • | paper received ※ 11 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW102 | CBETA - Novel Superconducting ERL | 1651 |
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Funding: New York State Research&Development Authority - NYSERDA agreement number 102192 We are successfully commissioning a unique Cornell University and Brookhaven National Laboratory Electron Recovery Linac (ERL) Test Accelerator ’CBETA’ [1]. The ERL has four accelerating passes through the supercon-ducting linac with a single Fixed Field Alternating Linear Gradient (FFA-LG) return beam line built of the Halbach type permanent magnets. CBETA ERL accelerates elec-trons from 42 MeV to 150 MeV, with the 6 MeV injec-tor. The novelties are that four electron beams, with ener-gies of 42, 78, 114, and 150 MeV, are merged by spreader beam lines into a single arc FFA-LG beam line. The elec-tron beams from the Main Linac Cryomodule (MLC) pass through the FFA-LG arc and are adiabatically merged into a single straight line. From the straight section the beams are brought back to the MLC the same way. This is the first 4 pass superconducting ERL and the first single permanent magnet return line. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW102 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW106 | Present Status of the PF-ring and PF-AR Operations | 1654 |
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| The Photon Factory at KEK has been managing two synchrotron radiation sources, the PF-ring and PF-AR, for over 30 years. Although their operation time has been decreasing in recent years for budget reasons, continuous efforts to improve their performance have been made. In this paper, the operational status of these light sources for FY2018 is described. At the PF-ring, a first-generation undulator was renewed with the beamline components. A vacuum chamber for the new undulator was applied the NEG coating on the inner surface. This is the first attempt in Japanese light sources that the NEG-coated chamber is used for undulators. At the PF-AR, the top-up injection using the direct beam transport line was introduced to the user operation for the first time. Since modification of the beam injector LINAC for enabling simultaneous injection to the four different rings (the PF-ring, PF-AR, SuperKEKB HER and LER) was completed, this top-up operation no longer disturbs the operation of the other three rings. A low-energy operation of the PF-AR was also tested to secure more operation time within the limited budget. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW106 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW107 | Overview of Collective Effects in SLS 2.0 | 1658 |
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| At the end of 2017, the conceptual design for an upgrade of the Swiss Light Source was finished, promising a 40 fold smaller emittance and a corresponding increase of the spectral brightness from the current value. From the point of view of collective effects, the main changes in the new design are a reduced chamber size, fully coated with NEG, and operation at small and negative momentum compaction with low synchrotron frequency. We give an overview of the latest results for the ring. Most critical is the threshold for the longitudinal single bunch instability. Taking into account the combined effect of wake impedances and CSR, we have to rely on bunch stretching by a higher harmonic system to achieve stable operation at nominal current. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW107 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW108 | Characterization of NEG Coatings for SLS 2.0 | 1662 |
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| To limit desorption and ameliorate pumping of the narrow 20 mm aperture vacuum chamber of SLS2.0, it is planned to fully coat it with nonevaporable getter (NEG) material. NEG coating can be produced with different structural characteristics, from dense films to columnar growth, with corresponding distinct electrical properties affecting the machine impedance and the instability threshold of the accelerator. In order to evaluate and characterize the coating process for geometries similar to the SLS chamber, we measured the resonance properties of coated and uncoated shorted waveguide pieces. First tests were done with standard X band waveguides at 12 and 7 GHz. Test setups using elliptical cross sections are in preparation, also for higher frequencies allowing the characterization of thin NEG layers. The final goal is to have a standardized process to test of samples coated by external producers. We describe the setups and first results. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW108 | |
| About • | paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW109 | Conceptual Design of Vacuum Chamber for SPS-II Storage Ring | 1666 |
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| The SPS-II is a 3 GeV ultralow emittance light source which is now under studied and designed by Thailand Synchrotron Light Research Institute (SLRI). The SPS-II storage ring is based on Double-Triple Bend Achromat (DTBA) cell with a circumference of 321.3 m aiming for horizontal emittance of less than 1 nm-rad. The compact lattice leaves narrow space for vacuum components. The small gap between poles of the magnets requires narrow vacuum chambers and limits the conductance of the chambers. The chambers will be made by stainless steel with a thickness of 1.5 mm. the cross section of beam duct is 40 mm × 16 mm elliptical shape. The bending chamber is designed as a long triangular chamber such that photon absorber can be installed as far from the light source as possible to lower the power density of the heat load. The overview of designed vacuum system for the SPS-II is presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW109 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW110 | Improvement of Touschek Lifetime by Higher Harmonic RF Cavity in the SPS Storage Ring | 1669 |
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| Siam Photon Source (SPS), located at Nakhon Ratchasima, Thailand, is a synchrotron light source with the beam energy of 1.2 GeV. User operation is performed in beam decay mode with the maximum current of 150 mA. Beam lifetime is about 12 hours at the beam current of 100 mA. Beam injection is carried out twice a day, and even with full energy, it takes roughly 30 minutes. Beam lifetime in the SPS storage ring is limited by Touschek scattering and strongly depends on operation conditions. Higher harmonic RF cavity is a proven method to increase the beam lifetime and suppressing coupled bunch instabilities through Landau damping effect. If the beam lifetime is increased for examples, to be double, only one injection per day would be needed. In this study, an improvement of Touschek lifetime by passive harmonic RF cavity is investigated. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW110 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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