| Paper | Title | Page |
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| WEPC001 | Status of PETRA III | 1977 |
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| PETRA III is a new hard x-ray synchrotron radiation source which will be operated at 6 GeV with a extremely low horizontal emittance of 1nmrad. This new light source will be the result of a conversion of the existing accelerator PETRA II into a light source. The conversion comprises the complete rebuilding of one eighth of the 2304 m long storage ring, which will then house 14 undulator beam lines and the modernisation and refurbishment of the remaining seven eighths. In addition two 100m long damping wiggler section will be installed which are required to achieve the small design emittance. During the last four years extensive design work, construction and production of components have been carried out to prepare for the conversion. Since the 2nd of July the construction activities have started when PETRA II was no longer needed as a pre-accelerator for HERA. At present the project is still on track so that operation with beam is foreseen for January 2009 and first user experiments in the second half of 2009. In this report a brief overview of the project and the status of the constructional work, the different components and the installation in the tunnel will be given. | ||
| WEPC002 | Analysis of Beam Orbit Stability and Ground Vibrations at the Diamond Storage Ring | 1980 |
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| With the aim of understanding and improving the beam orbit stability at the Diamond storage ring we launched an extensive campaign of ground and magnets vibration measurements in order to identify the sources of ground vibration and how they affect the beam orbit stability through the girder resonances. We present here the results of the measurements performed during 2007 along with a discussion of the possible remedies and the implications for the orbit feedback systems. | ||
| WEPC003 | Coupling Control at the SLS | 1983 |
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| The vertical beam size measurement at the Swiss Light Source (SLS) is based on vertically polarized visual light and allows to verify a vertical emittance of a few pm rad, resp. an emittance ratio in the 10-4 range obtained in 400 mA top-up user operation mode by tuning the lattice by means of 24 skew quadrupoles. Suppression of betatron coupling by local and global coupling correction prevents losses of Touschek scattered particles at the narrow vertical gaps of the in-vacuum undulators and thus protects these devices and increases beam lifetime, resp. the top-up interval. We will report on our experience with the beam size monitor, on the method of coupling control and on the achievements in vertical emittance and beam lifetime. | ||
| WEPC004 | Design Status of the Taiwan Photon Source | 1986 |
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| We report updated design works for a new 3-3.3 GeV synchrotron light source called Taiwan Photon Source (TPS). The lattice type of the TPS is a 24-cell DBA structure and the circumference is 518.4 m. The injector booster will be housed in the same tunnel. We present the lattice design, the accelerator physics issues and its expected performances. | ||
| WEPC005 | Design Considerations of the TPS Linac-to-booster Transfer Line | 1989 |
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| Design considerations of the linac to booster (LTB) transfer line for Taiwan Photon Source (TPS) project is described in this report. Electron beam from the linac with 150 MeV, 50 π-mm-mrad normalized emittance and 0.5% energy spread will be transferred to a booster synchrotron of 489.6 m. This LTB transfer line is designed with the flexible tuning capability and the diagnostics are included. Matching of transverse beam parameters from linac to booster is deliberated. The on-axis injection scheme with repetition rate around 2 or 3 Hz and efficiency with beta-mismatch for top-up operation is also studied. | ||
| WEPC006 | Beam Lifetime and Collective Effects in Taiwan Photon Source | 1992 |
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| The design of Taiwan Photon Source (TPS) has a natural emittance less than 2 nm-rad and low emittance coupling. The nominal rms bunch length is less than 3 mm. Several small-gap undulators are planned to provide x-ray photon beam with extremely high brightness. The vertical gap of these undulators are in the range of 5-7 mm. The TPS ring will be operated at top-up mode with high beam current. Various collective effects due to high beam current are investigated. Impacts of small-gap undulators to the beam lifetime are carefully studied. The results of theoretical analysis are presented. Proposals to overcome deleterious effects due to high beam current and small-gap undulators are also discussed. | ||
| WEPC007 | Vacuum Performance of the Diamond Light Source In-vacuum Insertion Devices | 1995 |
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| Diamond Light Source is the UK's new 3 GeV 3rd generation synchrotron light source with a 562 m circumference electron storage ring. At the start of user operations in January 2007, 5 in-vacuum undulators were in operation and a further 3 units have been installed subsequently. This paper describes the vacuum performance of these devices. 3 different mechanical configurations with different undulator canting angle and different pumping arrangements of the interconnecting vessels are installed. One configuration has non-evaporable getter (NEG) coated interconnecting vessels. Vacuum simulations were carried out on these configurations as part of the vacuum design process to predict their performance. Following final magnetic characterization, each of the devices was vacuum assembled and baked ex-situ for an extended period and then installed under dry nitrogen purge conditions, eliminating the need for a time-consuming in-situ bakeout in most cases. After a period of pump down and beam conditioning, the operating pressures in all the in-vacuum undulators were below the target specification and produced acceptably low Gas Bremsstrahlung radiation levels in the beamlines. | ||
| WEPC008 | Status of the SSRF Storage Ring | 1998 |
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| The SSRF storage ring is composed of 20 DBA cells with energy of 3.5GeV and circumference of 432m. The installation of the SSRF storage ring was started on June 11, 2007, and finished in the beginning of Dec. 2007. The system tests of hardware and software for storage ring were completed in the middle of Dec. 2007. The commissioning of the storage ring started on Dec. 21, 2007, and the 100mA stored beam was achieved for the first time on Jan. 3, 2008. The design, installation and commissioning of the SSRF storage ring are described in this paper | ||
| WEPC009 | Progress of ALBA | 2001 |
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| The construction of the ALBA Synchrotron Light Source in Barcelona (Spain) is well advanced. In spring of this year the 100 MeV Linac will be installed and results from the commissioning will be reported on this conference. The different components for the accelerators have successfully completed the prototyping phase and the different series are now under production. Installation of Booster and Storage Ring should start in summer of this year and commissioning is planned for spring 2009. The construction status will be presented. | ||
| WEPC010 | Upgrade of the ESRF Accelerator Complex | 2004 |
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The ESRF, the first third generation synchrotron radiation source, opened its first beamline in 1994 and has been continuously developed since then to satisfy the user community. However, the need arose to make a major upgrade of the infrastructure and accelerator complex in order to fulfil the request for new scientific applications*. The experimental Hall will be expanded and half of the beamlines reconstructed. The storage ring lattice will be modified to provide space for longer as well as a larger number of insertion devices. New insertion devices will be developed possibly based on in-vacuum permanent magnets at cryogenic temperature. The electron beam positioning system will be rebuilt to provide a higher photon beam stability. The RF system will face a major reconstruction with a new type of RF transmitters and HOM damped cavities allowing stable operation at a ring current of 300 mA without feedback. The injector system will be upgraded to operate the 16 and 4 bunch fillings in the top-up mode in order to increase the average current and obtain a higher photon beam stability.
*ESRF Science and Technology Programme, 2008-2017. |
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| WEPC011 | Using Multi-bend Achromats in Synchrotron Radiation Sources | 2007 |
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| Multi-bend achromats offer small electron beam emittance, large energy acceptance and a good dynamic aperture. Two examples are discussed in the article, each using 7-bend achromats; a 12 achromat lattice and a 20 achromat one. Some possible technical solutions associated with the dense lattices are discussed: magnet technology, vacuum system and RF system. Some characteristics of the two rings are also presented; effects of Intra Beam Scattering, Touschek life-time and the electron beam parameter values. | ||
| WEPC012 | Commissioning and Operation of the Metrology Light Source (MLS) | 2010 |
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| The Metrology Light Source (MLS) is dedicated to metrological and technological developments in the UV and EUV spectral range and in the IR and THz region. The new electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) is located next to the BESSY II storage ring in Berlin - Adlershof. The MLS with its 48 m circumference can be operated at any electron beam energy between 105 MeV and 630 MeV. The electron beam currents vary from 1 pA (one stored electron) up to 200 mA. These specific modes of operation were achieved during the initial one year phase of the commissioning of the storage ring until April 2008, when the regular MLS user operation started. The basis for this success was the previously commissioned microtron which is the main part of the injection system. | ||
| WEPC013 | Commissioning of Medium Emittance Lattice of HLS Storage Ring | 2013 |
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| Hefei Light Source (HLS) is a second generation light source, whose emittance is about 160 nmrad in normal optics. Lowering beam emittance is the most effective measure to enhance light source brilliance. Considering beam lifetime limitation, a lattice with medium beam emittance was brought forward. Through distributed dispersion in straight section, the beam emittance was reduced to 80 nmrad. At same time, the betatron tunes were kept same as before. In this way, the focusing parameters can be tuned to new one smoothly. With the new lattice parameters, the brilliance of HLS is increased by two factors. | ||
| WEPC014 | Beam Lifetime Studies of Hefei Advanced Light Source (HALS) Storage Ring | 2016 |
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| Hefei Advanced Light Source (HALS) will be a high brightness light source with about 0.2nmrad emittance at 1.5GeV. Ultra low beam emittance and relatively low beam energy of HALS would result in poor beam lifetime. Comparing the beam-gas scattering and Touschek scattering effects, a conclusion can be drawn that Beam lifetime will be affected strongly by Touschek scattering. Touschek lifetime has been studied considering linear and nonlinear effects for the lattice structure. Relations between lifetime and RF cavity voltage, lifetime and emittance coupling, lifetime and gap heights of insertion devices have been calculated respectively. After the optimization, proper cavity voltage and emittance coupling are chosen to get about 1.06 hours of total lifetime including gas scattering losses effect. Installing a third harmonic RF cavity can lengthen the beam bunch to increase the total lifetime to about 3.85 hours. Top up injection operation will be applied to keep bunch current within the required value. | ||
| WEPC015 | Baseline Design of HLS Linac Upgrade | 2019 |
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| The existing 200MeV linac of Hefei Light Source (HLS) mainly consists of electron gun, prebuncher, buncher, one 3m S-band linac section, and four 6m S-band linac sections. Energy gain of electron beam at the end of the linac is 200MeV and energy spread is ±0.8%. In order to improve the electron beam quality, An upgrade project is required. Four 80MW klystrons will be used to instead the old ones, which can improve the beam energy stability. This upgrade can also make it possible to increase the linac energy from 200 MeV to 400 MeV without changing the accelerating structure. In the meantime, New operation modes of HLS linac has been found by extensive computer modelling and optimization. Electron beam dynamics simulation from electron gun to the end of linac has been given, which considering space charge effects and wakefields. | ||
| WEPC016 | Operation Status and Performances Upgrade on SOLEIL Storage Ring | 2022 |
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| SOLEIL is the French 2.75 GeV third generation synchrotron light source delivering beam to users since January 2007. Beginning of 2008 up to 13 beam-lines are taking beam, 7 from insertion devices (IDs), 2 from IR ports, and 4 from dipole ports, and 6 of them are open to external Users. Users have a full control of their IDs. With a 300 mA stored beam current in multi-bunch filling pattern, and position stability in the few micron range, the main target performances have been reached. A beam of 50 mA in 8 bunches was delivered to users for the first time in December 2007 for time structure experiments. Operation and performance status will first be given, namely subsystem behaviour (RF, vacuum, …), beam optics, orbit stability, beam lifetime, and operation statistics. Then the main objectives for 2008 will be reviewed: delivery of 4000 hours of user beam time, installation and commissioning of a second cryomodule for reaching the 500 mA current target, construction and installation of 6 new IDs leading to a total number of 17, improvement of the orbit stability with a fast orbit feedback complementary to the slow orbit one, and preparation for top-up operation. | ||
| WEPC017 | Short X-ray Pulse Generation in Taiwan Photon Source Using Deflecting Cavity | 2025 |
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| We have purposed to use deflecting cavity for short X-ray pulses production in 3 GeV Taiwan Photon Source (TPS). Typical electron bunch length in TPS for 1.1MV RF gap voltage is about 5.7mm. Deflecting cavity generates correlation between longitudinal position and vertical momentum of particles in a bunch. Vertical kick of particle separates the photons that emit from ID vertically. Slit and asymmetric crystal in TPS beam line are used to compress the photon pulse duration. For a 60 m beam line of TPS, the operating of deflecting cavity up to 6MV voltage and eighth harmonic yields an FWHM pulse duration of radiated X-ray of about 0.48 ps for users. | ||
| WEPC022 | Operation and Recent Developments at the ESRF | 2028 |
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| The ESRF has been operating for a period close to fifteen years and is now looking towards an ambitious upgrade programme for the coming ten years. This paper reports on the performances achieved today with the ESRF storage ring, as well as developments accomplished and projects underway. These include a new filling mode for pump and probe experiments, the evolution of insertion devices, developments to improve beam stability, in particular transverse and longitudinal multibunch feedbacks, and the current increase from 200 to 300 mA. The upgrade of the lattice to accommodate longer straight sections and the new High Quality Power Supply system will also be presented. The machine reliability and the most important failures will be discussed. Finally, the use of an electronic logbook in routine operation will be presented, and the status on the control system including TANGO collaboration given. | ||
| WEPC023 | Ideas for a Future PEP Light Source | 2031 |
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| With the termination of operation of the PEP-II storage rings for high energy physics at hand, and with the migration of accelerator operation at SLAC in general to photon science applications, a study of the potential conversion of the PEP-II to a future light source has been initiated. With a circumference of 2.2 km and the capability for high current operation, it is clear that operating a converted ring at medium energy (3-6 GeV) could offer very low emittance and an average brightness of order 1022, limited primarily by the power handling capacity of photon beam line optical components. Higher brightness in the soft X-ray regime might be reached with partial lasing in long undulators if the emittance is sufficiently low, and high peak brightness could be reached with seeded FEL emission. Advanced pulsed rf technology might be used to generate short bunches and fast switched polarization in soft X-ray rf undulators. An overview of the preliminary findings of the PEP Light Source study group will be presented, including lattice, X-ray source and beam line options. | ||
| WEPC024 | Low Beta Structure for the ANKA Storage Ring | 2034 |
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| The ANKA storage ring has a fourfold symmetry with a double DBA structure. Four (~1.7 m) straight sections are used for the RF and the injection. Four sections (~ 4.5 m) are used for insertion devices (three installed). The beta functions in these sections are 14, respectively 7 m (horizontal/vertical). This is not ideal for small gap (7 mm) insertion devices. Reducing the vertical beta function to 2 m is possible with the present magnet configuration and is done for special user operation. Reducing both the horizontal and vertical beta function is favoured for one future beam line. This will afford a change of the present magnet configuration. Different options have been calculated and will be discussed. | ||
| WEPC025 | First 18 Months Operation of the Diamond Storage Ring RF System | 2037 |
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| Since the Diamond Light Source became operational in January 2007, the storage ring RF system has operated for 5000 hours in 2007 and is scheduled to operate for 5350 hrs in 2008. This paper presents some of the key challenges of the storage ring RF system including reliability, performance observations and future improvements. | ||
| WEPC026 | Laser – Beam Interaction and Calculation of the Sliced Bunch Radiation Spectra for the SLS FEMTO Beam Line | 2040 |
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| The FEMTO insertion at the Swiss Light Source (SLS) produces sub-ps X-ray pulses by modulating the electron energy in a slice of the bunch through interaction with a fs-laser. The electron energy modulation by the laser field in the wiggler magnet is studied analytically to calculate the radiation spectra from a sliced bunch. The analytical expressions for energy modulation and its envelope have been derived. The radiation spectra in the first magnet after the FEMTO insertion have been studied. The spectra of the coherent part of the radiation are determined using a Fourier transformation technique. For a Gaussian bunch the obtained results are compared with the tracking simulation study. | ||
| WEPC027 | Coherent THz Radiation at ELETTRA | 2043 |
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| Coherent infra red radiation (CIR) has been observed since some time at ELETTRA under several machine parameter settings in the beam-line SISSI. Effort has been made to produce a “stable” THz signal for experimental use. The description of the machine settings to that end and the measurements performed are presented and discussed. | ||
| WEPC028 | Status of UVSOR-II and Light Source Developments | 2046 |
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| UVSOR, a 750 MeV synchrotron light source of 53m circumference had been operated for more than 20 years. After a major upgrade in 2003, this machine was renamed to be UVSOR-II. The ring is now routinely operated with low emittance of 27 nm-rad and with four undulators. Top up injection is under preparation. The ring is equipped with a resonator type free electron laser. The shortest wave length has reached 200nm. Several user experiments in the deep UV region are in progress. Coherent terahertz synchrotron radiation and coherent harmonic generation are extensively studied by using an ultra-short laser system, under international collaborations. An upgrade plan of the ring is under consideration to improve the experimental setup of the light source developments. | ||
| WEPC029 | Assessment of the Impact of External Stimuli on the Floor Stability of Diamond | 2049 |
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| Continuous vibration monitoring is carried out and the stability of the Diamond floor slab has been assessed with regard to how it has responded to various external stimuli. Data has been collected on weather conditions and comparison made at extremes with floor vibration. The impact of a high level walkway bridge on the hall floor has also been assessed and there was a unique opportunity for an operational facility to measure the vibration response during a complete power black-out. The impact of local construction work is also presented. | ||
| WEPC030 | Diamond Light Source: Moving from Commissioning to Full Machine Operation | 2052 |
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| Diamond Light Source commenced routine operations in January 2007 providing light to beam lines for 3000 hours in 2007 with 4000 hours planned during 2008. During shut down periods Insertion Devices and photon Beam Lines, to utilise them, are being installed at a rate of four per year. The evolution of the performance of the machine during this period is described, including beam current, vacuum levels, beam lifetime etc. Machine operational statistics are also presented including a detailed fault analysis. Efforts that have been made to improve reliability are also discussed. On behalf of the Diamond machine staff. | ||
| WEPC032 | Absolute Measurement of the MLS Storage Ring Parameters | 2055 |
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| The Metrology Light Source (MLS), the new electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) located next to BESSY II in Berlin - Adlershof is dedicated to metrology and technology development in the UV and EUV spectral range as well as in the IR and THz region. The MLS can be operated at various electron beam energies up to approx. 600 MeV and at electron beam currents varying from 1 pA (one stored electron) up to 200 mA and is optimized for the generation of coherent synchrotron radiation. Of special interest for PTB is the operation of the MLS as a primary radiation source standard from the visible up to the X-ray region. Therefore the MLS is equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty. The instrumentation and measurement results for the determination of the storage ring parameters are presented. | ||
| WEPC033 | Coherent Synchrotron Radiation at the Metrology Light Source of the PTB | 2058 |
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| The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, has set up a low-energy electron storage ring in Berlin-Adlershof in close cooperation with the BESSY GmbH. The new storage ring, named Metrology Light Source (MLS), is mainly dedicated to metrology and technological developments in the EUV, VUV, and IR spectral range. Additionally, the MLS is the first machine designed and prepared for a special machine optics mode (low-alpha operation mode) based on an octupole correction scheme, for the production of coherent synchrotron radiation in the FIR and THz region. Two beamlines dedicated to the use of IR synchrotron radiation are now under commissioning: an IR bending magnet beamline optimized for the MIR to FIR and an IR edge radiation beamline. We report the status of the MLS operated in the low alpha mode and present first results from the commissioning. | ||
| WEPC034 | Present Status of Siam Photon Source | 2061 |
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| The Siam Photon Source (SPS) is a 1.2 GeV synchrotron light source situated in Nakhon Ratchasima, Thailand. It is currently in the fourth year of routine operation for synchrotron radiation users. In order to address the increasing user demand for increasing beamtime, better beam position stability, and improved machine reliability, several machine improvements and upgrades have been undertaken during the past year. This report first briefly gives the overview and important parameters of the light source, and then describes the current operation status and operation statistics in 2007. Recent machine improvements, for instance, modernization of injector components, improvement of vacuum system, recalibration of beam position monitors, and orbit correction, are presented together with the initial synopsis of the successful installation of the first insertion device, a permanent magnet planar undulator. | ||
| WEPC035 | Present Status of PF-ring and PF-AR in KEK | 2064 |
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| In KEK, we have two synchrotron light sources which were constructed in the early 1980s. One is the Photon Factory storage ring (PF-ring) and the other is the Photon Factory advanced ring (PF-AR). The PF-ring is usually operated at 2.5 GeV and sometimes ramped up to 3.0 GeV to provide photons with the energy from VUV to hard X-ray region. The PF-AR is mostly operated in a single-bunch mode of 6.5GeV to provide pulsed hard X-rays. Operational performances of them have been upgraded through several reinforcements. After the reconstruction of the straight section of the PF-ring in 2005, two short-period-gap undulators have been stably operated. They allow us to produce higher brilliant hard X-rays even at the energy of 2.5 GeV. In March 2008, the circular polarized undulator will be installed in the long straight section of 8.9 m. In the PF-AR, new tandem undulators have been operated since September 2006 to generate much stronger pulsed hard X-rays for the sub-ns resolved X-ray diffraction experiments. In this conference, we report present status of the PF-ring and the PF-AR. | ||
| WEPC037 | Preparations of BESSY for Top Up Operation | 2067 |
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| The synchrotron light source BESSY went into operation for users in 1998. BESSY was not designed initially to allow for Top Up operation, a mode where lost electrons are replaced after minutes while the beam shutters are open and users take data. Since 3 years the facility is improved in order to guarantee safe operation in this risky mode. The work culminated in a one week long Top Up test run at the beginning of this year. The efforts and achievements are described in detail: Improvements of the injector, the pulsed injection elements, the timing system, insertion devices, the additional safety interlocks, and the shielding of the ring. | ||
| WEPC039 | PLS Upgrade Plan | 2070 |
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| Pohang Light Source (PLS) has operated for 14 year successfully. To meet the request of the increasing user community, an upgrade plan of PLS is under consideration. The design goal is to achieve an emittance as low as 5 nm rad and to install as many insertion devices as possible. To minimize the necessary relocation of existing beamlines, the new lattice will still be a TBA. But, adopting combined function magnets, it is possible to achieve low emittance while the insertion straight is as long as 8.8 m where two insertion devices will be installed. The PLS upgrade plan and the lattice design will be presented in this paper. | ||
| WEPC040 | Commissioning of the SSRF Booster | 2073 |
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| The SSRF Booster, designed to accelerate the electrons from 150MeV to 3.5GeV, is a FODO structure synchrotron with 180m circumference and 2Hz repetition rate. The commissioning of the SSRF booster from the LTB transfer line started on Sept. 30th evening, 2007, the first turns of beam in the booster was obtained in 20 hours. With about 60 hours effective commissioning effort, the electrons were accelerated to 3.5GeV on October 5th morning, 2007. And then the first 3.5GeV beam was extracted to BTS transfer line on October 30th, 2007. In this paper, the SSRF booster is introduced and its commissioning results are presented. | ||
| WEPC041 | The Injection System of the SSRF Storage Ring | 2076 |
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| A multi-turn injection scheme with four kickers and two septa is used for injection into SSRF storage ring. The 3.5GeV electron beam from the SSRF booster is injected with 6.3 degrees horizontally. All injection elements are set in one 12m long straight section for the requirement of the top-up operation. Simulation and commissioning results will be presented in this paper, such as the injection efficiency and the disturbance on stored beam. | ||
| WEPC042 | Commissioning of the SSRF Storage Ring | 2079 |
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| The Shanghai Synchrotron Radiation Facility (SSRF) is a 3.5GeV synchrotron radiation light source under commissioning in Shanghai, China. The SSRF accelerator complex consists of a 150MeV linac, full energy booster and a 3.5GeV storage ring. The commissioning of the SSRF storage ring began on Dec. 21st evening, 2007, the first turn and 150 turns was observed in less than 12 hours with RF off and then the stored beam of 5 mA was achieved on Dec. 24th. On Jan. 3rd, 2008, the 100mA stored beam current were obtained in the machine for the first time. Since then, the storage ring has been brought close to the design parameters, and frequent operation with 100mA beam current has been down for making the vacuum chamber cleaning. In this paper, commissioning results of the machine is presented. | ||
| WEPC043 | Commissioning of 360 mA Top-up Operation at TLS | 2082 |
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| Taiwan light source started the 200 mA top-up operation in October, 2005, and subsequently, the stored top-up beam current was raised to 300 mA. Several machine issues were observed and solved during past two years. We study the possibility and ability of 360 mA top-up operation at Taiwan light source. | ||
| WEPC044 | Top-Up Safety Simulations for the Diamond Storage Ring | 2085 |
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| To ensure that it is not possible for a train of injected electron bunches to pass down an open beam-line during top-up operation at the Diamond Light Source, an extensive program of tracking studies has been performed. Various error scenarios have been investigated, with realistic magnetic field, trajectory, aperture and energy errors all taken into account. We describe the tracking methods used, scenarios considered and the interlocks required in order to maintain user safety during top-up operation. | ||
| WEPC045 | Alternative Lattice Settings for ALBA Storage Ring | 2088 |
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| ALBA is a 3 GeV synchrotron light source under construction in Spain. The lattice for the standard operational mode is based in a DBA-like structure, with finite dispersion in the straight sections and extra space in the arcs. This solution provides small emittance with a large available space for insertion devices, RF and diagnostic components, and large dynamic aperture and energy acceptance. Other optic modes has been investigated, in order to facilitate the commissioning procedure or to provide different operating modes to the users: pure achromatic lattice, without dispersion in the straight section; achromatic arcs, where the dispersion is zero in the long straight; or a relaxed lattice, offering higher emittance. This paper review the performance of this alternative options, including the non-linear performance. | ||
| WEPC046 | Characterizing THz Coherent Synchrotron Radiation at the ANKA Storage Ring | 2091 |
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| In a synchrotron radiation source coherent infrared (IR) radiation is emitted when the bunch length is comparable to the wavelength of the emitted radiation. To generate coherent THz (far IR) radiation, the ANKA storage ring is operated regularly in a dedicated low-alpha optics. Different bunch lengths, corresponding to different spectral ranges of the THz spectrum and various electron beam energies can be offered, depending on user demand. The radiation emitted in the fringe field of a dipole magnet, the so-called edge radiation, is detected at the ANKA-IR beamline. This paper presents radiation properties like THz beam profiles and power measurements in the framework of characterising the coherent THz radiation to optimise the power, frequency and spatial output of the ANKA storage ring. First experiments showed a time averaged power of up to 0.2 mW suggesting a THz pulse peak power of at least several tens of mW. | ||
| WEPC047 | Modeling the Shape of Coherent THz Pulses Emitted by Short Bunches in an Electron Storage Ring | 2094 |
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| A sufficiently short electron bunch will emit coherent synchrotron radiation of wavelengths equal to or larger than the bunch length. The shape of the emitted THz pulse depends amongst other things on the original shape and length of the bunch’s charge distribution. A Michelson interferogram of the THz signal therefore contains information on the generating bunch. However, systematic effects make a bunch length measurement based on that technique non-trivial. In order to understand the variables involved, an analytical model of the pulse generation is needed. In this paper, a derivation of the THz pulse shape form first principles with special emphasis in the time domain is presented. The impact of charge distribution parameters on the Michelson interferogram is discussed. | ||
| WEPC048 | Experimental Characterization of the Insertion Device Effects on Beam Dynamics at SOLEIL | 2097 |
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| SOLEIL, the French 2.75 GeV third generation light source, has been delivering photons to beam lines in routine operation since January 2007. The storage ring is presently equipped with eleven insertion devices: 3 in-vacuum 20mm period undulators (U20), 1 Apple-II type 52mm period undulator (HU52), 3 Apple-II type 80mm period undulators (HU80), 3 electromagnetic 256mm period undulators (HU256) and 1 electromagnetic 640mm period 10m long undulator (HU640). Commissioning of insertion devices consists of characterizing all the effects on beam dynamics in terms of focussing, injection efficiency, beam lifetime and sensitivity to working point, and also in optimizing feedforward tables in order to compensate for closed orbit distortions during field variations (this last point is detailed in other papers). We will focus here on the significant effects observed with some undulators. Measurements, using electron beam, of the transverse variation of field integrals, were helpful to understand bad effects impacting the daily operation. The introduction of real magnetic characteristics in the lattice model is in progress in order to further optimize the working point. | ||
| WEPC049 | Novel Schemes for Simultaneously Satisfying High Flux and TOF Experiments in a Synchrotron Light Source | 2100 |
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| Storage Ring Light Sources have proven to be extremeley succesful tools for probing matter. One of their most desirable features is that they are able to supply synchrotron radiation to multiple experiments simultaneously. However two classes of applications are difficult to satisfy simultaneously - high flux applications and time of flight applications. High flux experiments require filling as many buckets as possible while time of flight experiments require long gaps between bunches. In this paper we examine schemes for operating the synchrotron light source for for both communities simultaneously. | ||
| WEPC050 | Future Plans for the Advanced Light Source | 2103 |
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| The Advanced Light Source is now in its 15th year of operation. The facility has managed to continue to improve through continual upgrades to both the capabilities and capacities. Studies have shown that there is still plenty of room for improvements. Here we present plans to provide sustantial relevant improvements with modest cost. | ||
| WEPC051 | Upgrade Plans for the ESRF Storage Ring Lattice | 2106 |
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| The lattice of the ESRF storage ring is of the Double Bend Achromat type with 32 straight sections of alternating high and low horizontal beta values, currently providing 5 m of available space for insertion devices. As part of the ESRF Upgrade Programme, it is proposed to increase the length of selected insertion device straight sections from 5 to 7 m. In this paper, we will describe the different steps towards longer straight sections: implementation of a new lattice in which the straight section quadrupole triplets are replaced by doublets, design of modified straight sections with replacing the long quadrupoles by shorter ones and moving the adjacent sextupoles, experiments carried out to simulate the lattice symmetry breaking induced by a 7 m long straight section. | ||
| WEPC052 | Achieving Stability Requirements for Nanoprobe and Long Beam Lines at NSLS II. A Comprehensive Study | 2109 |
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| Driven by beam stability requirements at the NSLS II synchrotron a comprehensive study has been launched seeking to provide assurances that nanometer level stability at critical x-ray beam-lines is achievable, given the vibration environment at the selected site. Through this effort which represents the integration of an array of field measurements and a state-of-the-art model of wave propagation, the stability of special NSLS II beam-lines that push the envelope of beam size is quantified. In particular, the effects of ground vibration at the NSLS II site are studied both deterministically and stochastically to account for the stochastic nature of the disturbances arriving at the site and interact with the ring and the experimental lines. Validated numerical models are utilized in an effort to guide the design of sensitive lines. The objective is to both minimize vibration amplification as well establish a relative stability envelope between the beam extraction and imaging locations of the sensitive NSLS II beam-lines. | ||
| WEPC053 | An Experimental Study of Radiation-induced Demagnetization of Insertion Device Permanent Magnets | 2112 |
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High brilliance in the 3GeV new light source NSLS II is obtained from the high magnetic fields in insertion devices (ID). The beam lifetime is limited to 3h by single Coulomb scattering in the Bunch (Touschek effect). This effect occurs everywhere around the circumference and there is unavoidable beam loss in the adjacent low-aperture insertion devices. This raises the issue of degradation and damage of the permanent magnetic material by irradiation with high energy electrons and corresponding shower particles. It is expected that IDs, especially those in-vacuum, would experience changes resulting from exposure to gamma rays, x-rays, electrons and neutrons. By expanding an on-going material radiation damage study at BNL the demagnetization effect of irradiation consisting primarily of neutrons, gamma rays and electrons on a set of NdFeB magnets is studied. Integrated doses of several Mrad to a few Grad were achieved at the BNL Isotope Facility with a 112-MeV, 90-uA proton beam. Detailed information on dose distributions and particle energy spectra on the NdFeB magnets was obtained with the MARS15 Monte-Carlo code. This paper summarizes the results of this study.
Work performed under the auspices of the US DOE. |
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| WEPC055 | General Status of SESAME | 2115 |
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| An update of the status of SESAME is presented. SESAME is a third generation light source facility under construction in Allan, Jordan. The storage ring electron beam energy is 2.5 GeV, the beam emittance is 26 nm.rad and 12 straight sections are available for Insertion Devices. The injector consists of a 22.5 MeV microtron and 800 MeV booster synchrotron, with a repetition rate of 1 Hz. The SESAME building has been handed over on Dec. 2007 and this note focuses on the upgrade and installation plans for the SESAME injector system during the 2008. In the meantime, preparations of technical specifications for most of the storage ring subsystems are in progress. In this note the conceptual design of the storage ring’s bending magnet, pulsed magnets and their power supplies, RF system, shielding wall and the cooling system are presented. The tendering of these components is expected by mid 2008. | ||
| WEPC056 | Emittance Reduction by Longitudinally Varying Dipole Field | 2118 |
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| One of the most important matters for synchrotron radiation source is decreasing the beam emittance to increase the brightness. The electron beam emittance is almost determined by electron energy and the average H-function. For further improvement of the emittance, we can change the damping partition number by radially varying dipole field and can reduce the emittance. However, this method is not effective for a small emittance lattice due to its small dispersion function. We have studied the emittance reduction by longitudinally varying magnetic field in a bending magnet. The radius of curvature is assumed to vary with the function of nth degree (n=1,2,3,4). The emittance is calculated numerically for minimum emittance and achromat configuration. In this paper, we describe the details of calculated results and discuss the effectiveness of the method. | ||
| WEPC057 | Preparation for Top-up Operation at Diamond | 2121 |
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| We report on progress towards top-up operation of Diamond. We describe the extensive safety assessment that has carried out, including the measurements and simulations to assess the potential radiation doses in the case of poor injection efficiency or a top-up "accident", and the various levels of safety measures - procedures, software limits and personnel safety system interlocks - that have been implemented. We describe the top-up control algorithm, the technique used to maintain a given arbitrary filling pattern and the performance in practise. The work carried out to reduce the effect of the injection kickers on the stored beam is described, and the effect of the residual disturbance on user operation is discussed. The modifications to the timing system to provide hardware and software gating signals, and experience with the use of these, are also described. | ||
| WEPC058 | Operational Performance of the Taiwan Light Source | 2124 |
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| The Taiwan light source (TLS) is a 1.5 GeV third generation light source at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. It has been routinely operated since its opening in 1993. Several major machine upgrade projects have been undertaken and successfully completed in last 5 years, including implementing of digital bunch-by-bunch feedbacks, superconducting accelerating RF cavity, top-up mode injection, etc. The light source now moves forward to its era of mature operation. It delivers more than 5000 hours user time in 2007 with an up-time of more than 98% and a mean time between failures better than 80 hours. Here, we review its annual operational performance with detailed statistics and discuss the possible improvement directions of machine performance. | ||
| WEPC059 | Lattice Design of PEP-X as a Light Source Machineat SLAC | 2127 |
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| The lattice study for converting the High Energy Ring (HER) of PEP-II into a light source machine with minimal modifications is reported. In this design, a higher phase advance is used in the HER FODO lattice which reduces the emittance to 5 nm at 4.5 GeV without a damping wiggler, and to 0.4 nm with 116 m damping wiggler included in two straight sections out of six. We also study the possibility of replacing one of the six FODO arcs with eight DBA cells to provide additional dispersion free straight sections for the experimental beam lines. The DBA cells will reuse the existing HER and LER (Low Energy Ring) magnets for a minimal cost of the modification. The main parameters and beam dynamics properties of these lattices are presented. | ||
| WEPC060 | Studies on the Beam Current Dependent Phenomena in the BEPC-II Storage Rings | 2130 |
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| The upgrade project of the Beijing Electron Positron Collider (BEPC-II) has been being commissioned since Nov. 2006. Besides the commissioning of the luminosity, which is expected to be 100 times higher than the BEPC, the BEPC-II also provided beam to the synchrotron radiation users as a light source during these two years. Some beam current dependent phenomena, such as bunch lengthening, single beam instabilities, blow-up in collision, etc., in both collision and synchrotron radiation modes are observed in the machine performance. In this paper, some observations and analyses on these phenomena are given. | ||
| WEPC062 | The SRS at Daresbury Laboratory: a Eulogy to the World's First Dedicated High-energy Synchrotron Radiation Source | 2133 |
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| 2008 marks the last year of operation of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, which circulated its first 2 GeV beam in 1981. This paper provides a look back at the significant milestones passed on the way and records the achievements of many of those involved in its thirty-year programme. Many of the technologies and techniques developed at the SRS at Daresbury are now standard practice at synchrotron light sources around the world; and there are few light source laboratories that do not benefit from the skills of someone who spent their formative years working on the SRS. The provision of synchrotron light for the UK is now being met by DIAMOND, whose success is a testament to the skills of its designers, honed as they were on the SRS at Daresbury. These skills are now being used to design the UK’s next-generation light source, to provide the pulsed and longer-wavelength light that DIAMOND cannot. | ||
| WEPC063 | The Concept of Hefei Advanced Light Source (HALS) | 2136 |
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| The Hefei Light Source is a dedicated VUV and soft X-ray light source. The layout of magnet lattice limits the achievalbe beam emittance and available straight section for insertion device. To enhance competitiveness of National Synchrotron Radiation Laboratory in synchrotron radiation application research region, a concept of new dedicated VUV and soft X-ray synchrotron radiation light source was put forward, which is named Hefei Advanced Light Source. Comparing the advantages, difficulties and performance/foundation of energy recovery linac, linac-based free electron laser and storage ring based light source, the scheme of a 1.5GeV storage ring with very low beam emittance was adopted as the baseline design. At same time, a low emittance 1.5 GeV linac would be as its full-energy injector, which can provide ultra-short radiation pulse. The HALS would provide more brilliant and transverse coherent synchrotron radiation in the VUV and soft X-ray range to various users. | ||
| WEPC064 | The Possibility of Conversion of Hefei Light Source Storage Ring Into a Dedicated THz Radiation Source | 2139 |
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| In the future of National Synchrotron Radiation Laboratory, a new advanced VUV and soft X-ray light source would be contructed and provide synchrotron radiation with high brilliance and transverse coherence. At that time, the current HLS storage ring would be replaced by the new one. Instead of retire of the old ring, there is another case, that is upgrading current low energy storage ring as a dedicated THz light source. In this paper, the possibility of lattice upgrading were evaluated. And its performance was estimated according to exist theoretical model. | ||
| WEPC065 | The Lattice Design of Hefei Advanced Light Source (HALS) Storage Ring | 2142 |
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| The purpose of Hefei Advanced Light Source is to provide high brilliant and coherent synchrotron radiation in the VUV and soft X-ray range to synchrotron radiation users. To enhance high brilliance and transverse coherent, very low beam emittance is required. The design goal of beam emittance is lower than 0.2 nmrad, whose synchrotron radiation is fully transverse coherent beyond the 2.5nm. Considering achievable undulator radiation spectrum and energy dependence of emittance, the energy of storage ring is set as 1.5GeV. Limiting the circumference of storage ring, the more dipole and strong focusing are needed for lowering emittance. On the other side, strong chromatic sextupoles are needed to compensate large natural chromaticity. The storage ring became strong nonlinear. The linear optics and nonlinear dynamics of HALS storage ring were introduced in this paper. | ||
| WEPC066 | The Transport Line Upgrade Proposal of Hefei Light Source | 2145 |
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| The injector of Hefei Light Source is a 200 MeV linac. A 55m transport line transfer beam to injection point of storage ring. At current stage, the mismatch of phase space is a potential source limiting the injection efficiency and stable operation of light source. A new focusing configuration of transport line was put forward, where the Twiss parameters matching was implemented. A skew quadrupole was introduced to make horizontal dispersion function matching. This matching between transport line and storage ring would be helpful to improve injection efficiency of HLS storage ring. | ||
| WEPC067 | Optics for the ALBA Booster Synchrotron | 2148 |
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| The ALBA booster is a full energy injector of 3 GeV for top-up operation that will be installed in the same tunnel as the Storage Ring. Its large circumference of 249.6 m and the magnetic lattice with combined function bending magnets provide an equilibrium emittance as low as 9 nm rad. In this paper the linear optics functions, the aperture requirements and the gradient error tolerances in the dipoles and quadrupoles are discussed. The closed orbit correction scheme consists of 44 horizontal and 28 vertical correctors and 44 BPMs. A solution that requires a reduced number of BPMs has been studied as well. Chromaticity correction and dynamic aperture during the ramping have been also investigated. Finally, the injection and extraction schemes are described. | ||
| WEPC068 | Injection into the ALBA Storage Ring | 2151 |
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| Injection into the ALBA Storage Ring is performed at an energy of 3 GeV in a 7 m long straight section. The injection bump is performed with four kickers. Pulsed magnets are described, in particular the active septum magnet. Tracking of particles has been simulated over a large number of turns, taking into account the magnet errors, the sextupole fields and the physical apertures all along the machine. Specific requirements for top-up injection have been examined, such as a perfect closure of the injection bump, the residual vertical field and the leakage fields from the septum. | ||
| WEPC069 | A Possible THz Radiation Source with a Train of Short Pulses in the SPARC High Brightness Photoinjector | 2154 |
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| A radiofrequency electron gun followed by a compressor can generate trains of THz sub-picosecond electron pulses by illuminating the photocathode with a comb laser pulse. This structure of the beam can be used to produce coherent radiation. A feasibility study for a possible experiment at SPARC to be realized with the addition of a dedicated magnetic chicane is discussed. An optimization study of a magnetic chicane with a negative and variable R56 is studied, together with a set of parameters relative to the SPARC machine with the intent of demonstrating the feasibility of this experiment. The dynamics is studied within the SPARC system with the PARMELA code and with the RETAR code for the evaluation of the radiation. | ||
| WEPC070 | Further Optimisation of the Diamond Light Source Injector | 2157 |
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| The Diamond Light Source injector consists of a 100MeV linac and a 3GeV full-energy booster, and has been providing beam to the storage ring since September 2006. System optimisation has continued throughout the first year of user operation at Diamond. Beam losses on injection into both the booster and storage ring have been minimised by optimisation of operating parameters and the stabilisation of injection elements, particularly the elimination of a linac energy beat. High level software has been developed to monitor turn-by-turn BPM data, allowing booster chromaticity to be measured. The same software generates an automatic log of storage ring frequency spectra on injection, enabling the parasitic measurement of storage ring tune, and can be used to provide information on storage ring impedance and chromaticity. Further optimisation of single bunch injection has been carried out in preparation for top-up operation, and top-up capability has been extended to provide a single bunch filling mode for the storage ring. Injection into the booster at low energy has been demonstrated, providing a mode of operation for the injection system in the event of a linac klystron failure. | ||
| WEPC071 | Installation and Commissioning of the 100 MeV Preinjector Linac of the New Elettra Injector | 2160 |
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| A new full energy injector has been installed and commissioned at Sincrotrone Trieste, the Italian Synchrotron Light Source Facility in Trieste. It consists of a 100 MeV Preinjector Linac (PL) followed by a 2.5 GeV Booster Synchrotron (BS), that will fill the Elettra Storage Ring (SR) with 2.0 GeV and 2.4 GeV electrons. Here a complete description of the preinjector linac and its characterization in terms of beam parameters will be presented and discussed. | ||
| WEPC073 | Layout of the Beam Switchyard at the European XFEL | 2163 |
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| A unique feature of the European XFEL will be the possibility to distribute electron bunches of one beam pulse to different FEL beam lines. This is achieved by using a combination of fast kickers and a DC septum. Integration of a beam abortion dump allows a flexible selection of the bunch pattern at the FEL experiment, while the superconducting linear accelerator operates with constant beam-loading. We describe the principal scheme, the geometrical and optical layout and deal with stability and technical issues like the fast kicker development. | ||
| WEPC074 | The Injection and Extraction Kicker Magnets of the Elettra Booster | 2166 |
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| The design, realization and performance of the injection and extraction Kicker magnets of the Booster of Elettra are presented. A window-frame geometry has been chosen due to its transverse symmetry in order to obtain a good field symmetry. A suitable layout for in vacuum operation has been developed. The magnetic core is made by CMD 5005 ferrite blocks, assembled in a stainless steel case, obtaining a single module; one module has been used for the injection Kicker and two such modules, connected in parallel, have been used for the extraction Kicker. In both cases the magnet modules have been installed in stainless steel vacuum chambers. The design of the magnetic core has been checked using the well known 2D POISSON code, thanks to the fact that the magnet’s gap is narrow compared to its length. | ||
| WEPC075 | Recent Results and Future Perspectives of the SPARC Project | 2169 |
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| The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations, a Thomson backscattering source and a plasma accelerator experiment. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. As a first stage of the commissioning a complete characterization of the photoinjector has been accomplished with a detailed study of the emittance compensation process downstream the gun-solenoid system and the demonstration of the emittance oscillation in the drift. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the “invariant envelope” matching and the demonstration of the “velocity bunching” technique in the linac. In this paper we report the experimental results obtained so far and the scientific program for the near future. | ||
| WEPC076 | Remote Tilt-control System of Injection Bump Magnet in the SPring-8 Storage Ring | 2172 |
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| The SPring-8 storage ring has four pulse-bump magnets to generate bump orbit for beam injection. Rotational error of the bump magnets around a beam-axis (tilt) induces the stored-beam oscillation in vertical direction due to horizontal error field. In the top-up operation, vertical perturbation of the stored-beam during beam injection is mainly produced by the tilt. We evaluated the tilt angle by measuring of the perturbation turn-by-turn using a single-pass BPM system and realigned bump magnets manually inside the accelerator tunnel. It was required to repeat the measurement and realignment processes two or three times for convergence. To correct the tilts smoothly, we developed a remote tilt-control system. The system consists of two fixed and one movable supports in vertical direction under each bump magnets. The movable support is driven by a stepper motor through 1/30 worm gear in the range of ±4 mrad with the accuracy of less than 0.1 mrad. By using this system, we succeeded complete on-beam reduction of the perturbation. | ||
| WEPC077 | Pulsed Magnet Systems for the SSRF Injection and Extraction | 2175 |
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| The injector and the storage ring of the Shanghai Synchrotron Radiation Facility (SSRF) have been built and the commissioning procedure and results are satisfactory. Total of fourteen pulsed magnets are used for the SSRF injection and extraction. In-vacuum ferrite kicker magnets, eddy current septa and 200ms bump magnets are offered for booster injection and extraction. A symmetric bump of stored beam is performed in one of the long straight section of the SSRF storage ring. Four identical kickers with ceramic vacuum chamber and two septa with a sheet of magnetic screening material around the stored beam are equipped for the storage ring injection. The septa can reach maximum 900 Tm field at 8600A with less than 0.01% leakage field for stored beam. And the identical 3.8 us half-sine pulse waveform is excited on the kicker magnets with 3.6kA current and exacted timing. The stability of ±0.05% (rms), low leakage field and identical bump are emphasized so that the residual closed orbit disturbance can be minimized for top-up injection. | ||
| WEPC078 | Eddy Current Septum Magnets for Booster Injection and Extraction and Storage Ring Injection at SSRF | 2177 |
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| There are 6 in-vacuum eddy current septum magnets used for injection and extraction in the SSRF booster and storage ring. The booster extraction thick septum magnets generate magnetic field over 1 Tesla, special attentions were paid to coils and their support design because of the shock force and the high heat which is hard to be dissipated in vacuum environment. The good transverse homogeneity in the gap has been achieved by careful design, precise machining and accurate assembly. An extremely low leakage field on the stored beam is another key feature of these magnets thanks to the high permeability Mu metal. Magnetic field measurement was conducted with both point coil and long integral coil, and the results agreed well with the OPERA-2d/3d simulations. An inner tube with RF finger flanges at each end is added to keep the continuity of impedance for the circulating beam. There is no vacuum separation between the inner tube and magnet chamber. | ||
| WEPC079 | Elettra Booster Commissioning and Operation | 2180 |
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The new injector, consisting of a 100MeV linac and a 2.5GeV booster synchrotron, replaced the old limited energy 1.2GeV linac by the end of 2007*. The paper reports on its commissioning phases and results together with its present status of operation.
*"Overview of the Status of the Elettra Booster Project", WEPC090, these proceedings. |
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| WEPC081 | Improvement on Pulsed Magnetic Systems at SOLEIL | 2183 |
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| Two "machine study" kicker systems have been designed, built and installed on the storage ring of SOLEIL to kick the stored beam in the horizontal and the vertical planes, in order to investigate the non-linear dynamic of the ring with different insertion devices configurations. This article will describe the different aspects of the design of the two magnets and vacuum chambers, and of their fast high current pulsed power supplies, working with high voltage switches based on MOS transistors. The electrical and magnetic measurements will be presented. The second part of the paper will describe the modifications brought to the thick septum magnet system of the ring injection, in view to reduce the stray field seen by the stored beam. It also presents the different tunings performed on the four injection kickers, in order to reduce the amplitude of the residual bump along the ring down to a very low level. Theses adjustements are aimed to minimize the disturbances on the stored beam when operating the Synchrotron in "Top Up" injection mode. | ||
| WEPC082 | Technical Considerations of the TPS Linac | 2186 |
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| The technical considerations of the TPS (Taiwan Photon Source) linac will be presented in this report. A 150 MeV turn-key linac is chosen in this case in order to provide the ease of injection into the booster in which the electron energy will be raised up to 3 GeV. This linac will be similar to that equipping at recently commissioned synchrotron light sources. The major beam parameters are derived from the booster and storage ring injection requirements. The beam diagnostics arrangement for linac commissioning purpose will be briefly described. | ||
| WEPC083 | Status of the SSRF Booster | 2189 |
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| The SSRF booster is a 2Hz electron synchrotron. It accelerates electrons, coming from a 150 MeV linac, to a final energy of 3.5 GeV in 250ms and extracts them into the storage ring. The booster lattice is based on a FODO structure with missing dipoles, forming 28 cells with 8 straight sections of a 2-folder symmetry and 180m circumference. The SSRF injector (Include 150 MeV linac, booster and two transport lines) was designed for Top-Up injection, which has single-bunch and multi-bunch beam modes. After 9 months installation and pre-commissioning, the SSRF booster commissioning started on September 30, 2007. The first 3.5GeV beam was obtained On Oct.5, and the first extracted beam was obtained on Oct.29, 2007. The booster serves as a injector for storage ring from Dec. 21, 2007. In this paper, the design, installation and commissioning of the SSRF booster and transport lines are described. | ||
| WEPC085 | Matching with Space Charge | 2192 |
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| This paper explores the possibility of performing matching in the presence of space charge to an acceptable and useful level. Space charge gives rise to a mismatch for beams at low energies. This mismatch can be very harmful for certain applications, for example the tomography diagnostic of the PITZ2 test line. In this case, the Twiss parameters at the start of the tomography section have to be as close as possible to the design ones. As can be shown by a thin lens approximation, all the Twiss parameters at the start of the tomography section are fully determined, as is the quadrupole strength, once the length of the FODO cells is chosen. With the presence of space charge it is necessary to introduce a modification to the original matching, itself performed with a standard optimizing routine. The idea is that this modification can only compensate for the linear part of space charge and it does so by changing the quadrupole strengths. The theory is verified by using an very simple test line consisting of just two quadrupoles and modeling it using GPT (General Particle Tracer). This results in modified values for the quadrupole strengths to accommodate the effect of space charge. | ||
| WEPC087 | New Preinjector for the ESRF Linac | 2195 |
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| A new preinjector of the 200 MeV Linac is under manufacture at the ESRF. Two operation modes are foreseen, a short pulse of 1ns-.4nC and a long pulse of 1000ns-10nC. The new triode type thermionic 100 Kev gun has been characterized experimentally. The transverse and longitudinal phase space measurements are compared with simulations. The design and the expected performance of the final set-up which includes vertical deflecting plates, pre-bunching and bunching sections will be presented. | ||
| WEPC089 | Status of the NSLS-II Injection System Design | 2198 |
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| NSLS-II is a new ultra-bright 3rd generation 3GeV light source planned to be built at Brookhaven National Laboratory. The design of this facility is well under way. The requirement for the compact injector complex which has to continuously provide 3GeV electrons for top off injection into the storage ring is very demanding: high reliability, low loss, relatively high charge (10nC). The injector consists of linear accelerator, a full-energy booster, as well as transport lines and injection straight section. A large three dimensional dynamic aperture through the entire acceleration cycle in the booster synchrotron is required. Tolerances on pulsed magnets for the beam transfer are very tight in order to minimize injection losses and disturbance of the stored beam in the main ring. The components of the injector are optimized for high reliability and availability. In this paper we give an overview of the NSLS-II injector, discuss status, specifications and design challenges. | ||
| WEPC090 | Overview of the Status of the Elettra Booster Project | 2201 |
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| The Elettra Booster Project is in its final phase. The 100 MeV linac pre-injector and the 2.5 GeV booster were constructed and installed on schedule and within the foreseen budget. Elettra was shut down during the last autumn to switch from the old linac injector to the new booster. The new 2.5 GeV transfer line was successfully connected to the storage ring by December 2007. During the same period the booster commissioning was started. Operation for users of the light source, with the booster as injector, is scheduled in March 2008. An overview of the booster systems and of the current status of its commissioning and operation is presented and discussed here. | ||
| WEPC091 | Beam Injection by Use of a Pulsed Sextupole Magnet at the Photon Factory Storage Ring | 2204 |
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| We will install a pulsed sextupole magnet (PSM) in order to test a new injection system for the top-up injection at the Photon Factory storage ring (PF ring) in the spring of 2008. A parabolic magnetic field of the PSM can give an effective kick to the injected beam that passes a distant region from the field center. And there is little modulation of the orbit of the stored beam because it passes around the center of the PSM. To achieve the beam injection at the PF ring, the PSM has a length of 0.3m, a magnetic field of 400 Gauss at a peak current of 3000A and a pulse width of 2.4μsec in a half-sine form. We already made the PSM and measured the magnetic field. We will report the result of the PSM beam injection at the PF ring. | ||
| WEPC092 | A Pulsed Quadrupole Magnet Injection at the PF-AR Storage Ring | 2207 |
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| We have examined a beam injection system that used a pulsed quadruple magnet (PQM) at the PF-AR storage ring since the spring of 2004. The system is operating well and the accumulation of the beam up to 60mA in the single bunch operation is possible by the current state. The beam injection system that uses the PQM does not require a conventional injection bump orbit, and has the feature that only one PQM in the injection part is needed. An injected beam is kicked to be proportional to the distance from the center and captured afterwards. On the other hand, the pulse kick hardly influences the stored beam at the magnetic field center of the PQM. We report on the result of collecting the basic data of the influence on the PQM beam injection at the PF-AR storage ring. | ||
| WEPC093 | Finalized Design of the Pulsed Magnets and their PS for SESAME Ring Injection | 2210 |
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| The design of the SESAME storage ring injection pulsed magnet systems have been improved in order to take benefit of the most recent realizations in Synchrotrons. These pulsed systems are optimised for the injection into the 2.5GeV storage ring of the 800 MeV electrons beam prepared by the Booster. The septum magnet is based on a direct driven septum technology, out of vacuum, with a thin vacuum chamber of rectangular cross section permitting to get a good field transverse homogeneity. The four kicker magnets will be of the window frame geometry, around a racetrack alumina vacuum chamber, integrating a forced air cooling in order to avoid significant thermal heating due to the stored beam. These magnets can be opened for backup and will be completely CEM shielded. Their pulsed power supplies will be built based on solid-state HV switches, even for short half-sine pulses generation. | ||
| WEPC094 | Thermo-Cathode RF Gun for BINP Race-Track Microtron-Recuperator | 2213 |
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| In 2007 the thermo-cathode RF gun for the Budker INP energy recovery linac (ERL) was designed. The RF gun is capable to emit the electron bunches with the energy of 300 keV, average current of 100 mA, and repetition frequency of 90 MHz. The new injector is adapted to the existing RF system for beam bunching, accelerating and injecting to the linac of the microtron. Its advantage is the absence of high potential of 300 kV at the control circuits of the cathode; therefore the maintenance is simplified. Also due to the absence of the cathode back bombardment by residual gas ions in the RF cavity, the lifetime of the cathode is increased and the obtaining of the repetition frequency up to 90 MHz becomes feasible. In the paper the main characteristics of the injector, its design and results of beam dynamics calculations with optimised regimes are presented. | ||
| WEPC095 | Progress in Raising the Energy of the CAMD Linac to 300 MeV | 2216 |
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| The possibilities and methods for higher energy injection at CAMD have been discussed previously. All components of the former HELIOS 1 linac have now been transferred to CAMD from Jefferson Laboratory. It is planned to reconfigure the CAMD injector linac by installing one of the HELIOS accelerating sections in addition to the two existing CAMD sections, thereby increasing the energy to 300MeV. The optimum arrangement for installing the 300 MeV linac in the existing tunnel has been established. Meanwhile, the arrangements and upgrades of sub-systems are being prepared, simulations of the electron beam trajectory by MATLAB based linear accelerator program are being made, and recommissioning the major HELIOS linac components is underway. In the paper, the detailed technical design of the 300 MeV linac is proposed, the key parameters of the linac are presented, and the benefits of 300 MeV injection to the CAMD synchrotron radiation light source are mentioned. | ||
| WEPC096 | APPLE Undulator for PETRA III | 2219 |
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| Currently, the storage ring PETRA is being rebuilt to a light source with an ultra low emittance of only 1nm rad. The undulator radiation will take full advantage of this high performance. PETRA III will also provide circularly polarized light and linearly polarized light under arbitrary angles (inclined mode) within the energy range of 250-3000eV. The light will be produced with an APPLE II undulator which is under construction at BESSY at present. The total length of 5m and a minimum gap of only 11mm cause strong 3D forces. Due to the small good field region in an APPLE undulator and a small stay clear between the magnets and the vacuum chamber a sophisticated mechanical layout is required. The design will be presented, the expected residual mechanical deformations will be given and the consequences for the spectral performance will be discussed. | ||
| WEPC097 | Active Shimming of the Dynamic Multipoles of the BESSY UE112 APPLE Undulator | 2222 |
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| APPLE undulators produce strong dynamic multipoles in the elliptical and inclined mode which can significantly reduce the electron beam dynamic aperture. The multipole strength scales with the square of the period length and the inverse of the electron energy. A large horizontal dynamic aperture is essential for top up operation. For the BESSY devices the dynamic multipoles generated in the elliptical mode have efficiently been compensated with iron shims. For the inclined mode no passive compensation scheme is available. In case of the strong BESSY 112mm APPLE device flat current wires have been glued onto the undulator chamber, which permit the cancellation of arbitrary multipoles. The full horizontal dynamic aperture has been recovered in the inclined mode. Tracking simulations and measurements of the electron beam performance for uncompensated and compensated dynamic multipoles will be presented. | ||
| WEPC098 | Development of Cryogenic Undulator CPMU at SOLEIL | 2225 |
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| On SOLEIL at 2.75 GeV, producing hard X rays requires short period and small gap in-vacuum hybrid permanent magnet undulators. Besides, higher achieved peak magnetic field can be while operating at cryogenic temperature Tc (around 140 K). When cooling down the permanent magnets, the remanence Br increases down to a certain temperature at which the process is limited by the appearance of the Spin Reorientation Transition phenomenon. The coercivity is also increased at Tc which improves significantly the resistance to radiation. R&D studies, aims at replacing SmCo by NdFeB permanent magnets whose Br of 1.4 T, could enable to increase at least by 30% the peak magnetic field at Tc. Unfortunately such magnet grade can’t be heated to high temperature without degrading the magnetic properties, which limits the residual pressure that can be achieved. Temperature gradient and mechanical deformation are also technical issues. Different permanent magnet grades at Tc are characterized. Studies are also carried out on a small assembly of four periods. Residual pressures obtained with or without partial baking on standard U20 in-vacuum undulators are compared. | ||
| WEPC099 | A Superconductive Undulator for the Munich Laser-plasma Accelerator | 2228 |
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| Laser-plasma accelerators are expected to produce electron beams with bunch charges in the nano-Coulomb range with energies in the GeV range. By employing short-period superconductive undulators this may be utilized for the generation of undulator radiation in the X-ray regime with a compact laboratory-sized set up. In this contribution we report on the project of testing this concept at the Laser-Plasma Accelerator in Munich. A particular aim of this project is to push the superconductive undulator technology to shortest periods and highest on-axis fields at gap widths sufficiently large to reduce the impact of resistive wall wake fields on the electron beam. This might open a path to the generation of coherent radiation via the SASE process. | ||
| WEPC100 | Superconducting Insertion Devices with Variable Period Length | 2231 |
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| The tuning range and functionality of superconducting insertion devices may be significantly enhanced by period length switching. Period length switching can be achieved by employing two or more individually powerable subsets of superconducting coils in such a way that a current reversal in a part of these coil sets results in a period length variation. In this paper the opportunities and restrictions of period length switching in superconducting undulators are discussed from a general point of view. As a particular example, the design of a hybrid superconducting undulator/wiggler (SCUW) for ANKA based upon the period length switching technique is presented. | ||
| WEPC101 | Improved Homogeneity of Permanent Magnets for Undulators and Wigglers | 2234 |
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| The homogeneity of permanent magnets for use in undulators and wigglers were significantly improved in close collaboration between industry and scientific institutes throughout the last three years. Magnets with a variation of less than ± 1% in remanence, ± 1° magnetic angle and ± 1% hot/cold-side effect can be produced now - a variation of the magnetic angle of less than ± 0.5 ° is possible for some products. The development was assisted by improved characterization equipment for magnetic dipole moment and magnetic inhomogeneities by the scientific partners, which was made available for industrial application at Vacuumschmelze. | ||
| WEPC102 | Commissioning of the Electromagnetic Insertion Devices at SOLEIL | 2237 |
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| SOLEIL is the French 2.75 GeV third generation synchrotron radiation light source. Eleven undulators are installed yet in the storage ring and nineteen more Insertion Devices (ID) will be installed on the ring by January 2010. Among the installed IDs, there are four electromagnetic undulators of two different designs: one 640 mm period air coils undulator called HU640 and three 256 mm period undulators called HU256, made up of independent H yoke dipoles. The HU640 provides photons in any polarisation from linear to elliptical, in a range extending from 5 to 40 eV, thanks to three different groups of coils powered independently. The HU256, which are subject to hysteresis, provide horizontal and vertical, periodic or quasi-periodic linear polarisations, and also circular polarisation, covering a total range from 10 eV to 1 keV. The effects of each undulator on the closed orbit have been extensive studied, and compensated, using dedicated embedded steering coils. The correction method will be explained and its results will be shown and compared to the magnetic measurements. Finally, the first measurements of the radiation produced will be shown and compared to previsions. | ||
| WEPC103 | Design of a Cold Vacuum Chamber for Diagnostics | 2240 |
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Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are:
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| WEPC105 | Construction of a Cryogenic Permanent Magnet Undulator at ESRF | 2243 |
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| A cryogenic permanent magnet undulator (CPMU) has been constructed at ESRF. The device is a full scale in-vacuum undulator with a magnetic length of 2 metres and a period of 18 mm. This prototype is still compatible with an operation at room temperature, it has been mainly used to investigate the technological issues connected to the operation at low temperature. An important effort has been dedicated to the construction of a complete measuring bench operated in-vacuum with the undulator at cryogenic temperatures around 150 K. The bench includes a stretched wire system for field integral measurement and a local field measurement assembly suitable for the accurate characterization of the optical phase error along the undulator. The main results of the magnetic measurements will be presented , they confirm the simulations performed with RADIA using NdFeB permanent magnet material models at low temperature. The cryogenic system used to cool the undulator is based on a reliable liquid nitrogen closed loop. The heat budget of the device will be discussed. The prototype has been installed on the ESRF ring in December 2007. The first results of operation will be presented. | ||
| WEPC106 | Compensation of Variable Skew- and Normal quadrupole Focusing Effects of APPLE-II Undulators with Computer-aided Shimming | 2246 |
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| Variable (phase- and gap-dependent) skew- and normal-quadrupole focusing effects of APPLE II undulators on electron beam are reportedly complicating practical use of this type of insertion devices in many synchrotron radiation sources. We show that these undesirable effects, whatever their "origin", can be well controlled and in many cases efficiently compensated during the standard "virtual" shimming of APPLE-II undulators. Our method exploits small variations of the skew- and normal-quadrupole focusing components resulting from extra magnetic interaction, introduced by displacements of permanent magnet blocks during the shimming procedure, at different undulator phase and gap values. These variations can be calculated to a high accuracy, included into the corresponding "shim signatures" of magnetic field integrals, and used, along with undulator magnetic measurements data, for calculation of the most efficient magnet displacements. This approach is well suited for a computer-aided (e.g., genetic optimization based) shimming procedure. Practical results obtained with several APPLE-II undulators, which are currently successfully operating on the SOLEIL storage ring, are presented. | ||
| WEPC107 | Observation and Interpretation of Dynamic Focusing Effects Introduced by APPLE-II Undulators on Electron Beam at SOLEIL | 2249 |
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| The paper presents the results of electron beam closed orbit distortion (COD) and tune shift measurements performed on three different APPLE-II type undulators when making horizontal displacements of the electron beam orbit in those straight sections of the SOLEIL storage ring where these undulators are installed. In agreement with data from other storage rings, our results show that, when APPLE-II undulators are used in elliptical, linear-vertical or linear-tilted polarization modes, the measured tune shifts and the COD can not be explained only by residual first-order focusing effects: taking into account the second-order, or dynamic focusing effects, is necessary. We describe a COD interpretation method allowing for straightforward comparison of the measured effects on electron beam with the corresponding predictions from calculations and magnetic measurements. The observed dynamic effects are in good agreement with calculations performed using RADIA code. We also discuss possible modification of the figures of merit to be used at computer-aided shimming of APPLE-II undulators, which would allow for simultaneous minimization of the first- and second-order focusing effects. | ||
| WEPC108 | Portable Magnetic Field Measurement System | 2252 |
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| This portable magnetic field measurement system is a very sophisticated and sensitive machine for the measurement of magnetic fields in undulators (Planer, EPU, and Apple II), wigglers, and in-vacuum ID units. The magnetic fields are measured using 3 axis hall-effect probes, mounted orthogonally to a thin wand. The wand is mounted to a carriage that rides on vacuum air bearings. The base is granite. A flip coil is provided on two vertical towers with X, Y and Theta axes. Special software is provided to assist in homing, movement, and data collection. | ||
| WEPC109 | Development of an In-vacuum Undulator System for U-SAXS Beamline at PLS | 2255 |
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| The design of a hybrid in-vacuum undulator with 20mm period, effective peak field of 1.05 Tesla, and 1800 mm magnetic length is being presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and finite element analysis, magnetic design, and electrical considerations that influenced the design are then analyzed. This in-vacuum undulator (IVUN) is being installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline. The IVUN will generate undulator radiation up to ~14 keV using higher harmonic (upto 9th) undulator radiation with 2.5 GeV PLS electron beam. | ||
| WEPC110 | Development of a Conventional Multipole Wiggler MPW-80 | 2258 |
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| The design for an 80 mm period hybrid wiggler is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and finite element analysis, magnetic design, and electrical considerations that influenced the design are then analyzed. This wiggler will be installed at ALBA a new synchrotron radiation source being built at the site of the Centre Direccional in Cerdanyola del Vallès, nearby Barcelona, and will produce ultra-violet and X-ray beams of exceptional brightness. The facility will comprise a 3 GeV electron storage ring, injected from a ~100 MeV linac through a full energy booster synchrotron. | ||
| WEPC111 | Latest Progress in Insertion Devices at ACCEL Instruments | 2261 |
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| ACCEL Instruments GmbH has designed, manufactured, and tested several insertion devices for synchrotron light sources and free electron lasers around the world. ACCEL has been awarded for the construction of two In – Vacuum – Undulators for the ALBA/CELLS synchrotron light source in Barcelona, Spain. The design originates from the standard ESRF IVU based on the license agreement with their ID group. The status of the design work will be summarized. Also ACCEL is manufacturing two granite measurement benches for the FERMI project at Elettra in Trieste, Italy. Both benches are designed to characterize insertion devices in a fast and accurate way. A summary of the commissioning results will be presented. A full functional prototype Hybrid Undulator for the European X-FEL project in Hamburg was delivered successfully and, as the first device, in full compliance with the technical specification. Also the industrial study requested by DESY for the adaptation of the design towards a large series production of 5m long undulators for the European X-FEL, was completed as the first one in full compliance with the DESY specification and the basic conclusions are presented. | ||
| WEPC112 | The Acceptance and Photon Beam Formation in SLS FEMTO Beamline | 2264 |
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| The FEMTO insertion at the Swiss Light Source (SLS) produces sub-ps X-ray pulses by modulating the electron energy in a slice of the bunch through interaction with a fs-laser. The radiation from the sliced bunch in the FEMTO undulator of the SLS storage ring has been studied. Only photons passing all apertures of the beam line arrive at the experiment. We derive the transverse phase space distribution of these photons, the radiation spectra, and the spatial and angular distribution. Transmission of the radiated photons through the FEMTO beamline is calculated using the SRW simulation code in order to evaluate the acceptance of the beamline and the photon beam phase space distribution at the experimental station. | ||
| WEPC113 | Heat Load Issues of Superconducting Undulator Operated at TPS Storage Ring | 2267 |
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| The superconducting undulator with periodic length of 1.5 cm and magnet gap of 5.6 mm has been studied. The magnetic flux density of 1.4 T has been achieved. However, the heat loads from image current of the electron in the storage ring and the synchrotron radiation from bending magnet are the critical issues. The calculated power from the image current and the synchrotron radiation of bending magnet are about 3.5 W/m and 1.7 W, respectively. The superconducting undulator will be operated at the 3 GeV TPS storage ring that the operation current and the magnet flux density of dipole magnet is 400 mA and 1.19 T, respectively. The superconducting RF cavity will be installed in the TPS such that the bunch length is only 2.8 mm. Hence, the superconducting Landau cavity is necessary to extend the bunch length for reducing the heat load on the beam duct. In addition, some strategies are needed to be studied to avoid the synchrotron radiation heating on the 4.2 K vacuum chamber. The soft-end dipole design and the chicane mechanism are studied to solve the issue herein. | ||
| WEPC114 | Improved Winding of Superconducting Undulator and Measurement of Quenching Tolerance | 2270 |
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| The superconducting (SC) wire windings of the mini-pole superconducting undulator at National Synchrotron Radiation Research Center (NSRRC) have an improved performance. A precise measurement of the magnetic field was undertaken to examine the quality of the wire winding. We improved the insulation between wires and the iron pole to avoid SC wire degradation when the coil was trained up to high current. A Teflon coating (layer thickness 0.035-0.045 mm) on the iron pole is capable of providing insulation to 0.5 kV. We pasted extra Teflon tape (thickness 0.12 mm) on the coating layer; this Teflon tape serves as a buffer that avoids the SC wires scraping the Teflon coating layer during adjustment of the position of the SC wire during winding. A quenching experiment was also performed to detect the heat tolerance of the SC wires during extra heating of the beam duct; a heating tape (Ni80Cr20) simulated the heating of the beam duct by synchrotron radiation. The SC wires and heater are separated by the stainless steel (SS) beam duct (thickness 0.3 mm) and an epoxy layer (thickness 0.1 mm). This result is an important issue in cryostat design. | ||
| WEPC115 | Development of IVUN at Pohang Accelerator Laboratory | 2273 |
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| Pohang Accelerator Laboratory (PAL) is developing In Vacuum Undulator (IVUN). A short magnetic length (about 1.0 m) IVUN with 24 mm magnetic period will be developed first and a longer IVUN with 1.8 m magnetic length which will be installed in the PLS storage ring will follow. The IVUN will be equipped with built-in magnetic measurement system to ensure the accuracy of the assembly, any degradation coming from the radiation damage or high temperature. Basically, a hall probe system will be installed with linear guide to translate the measurement assembly. In this report, the design issues related to the vacuum system, measurement system, and other engineering problems of the IVUN will be discussed. | ||
| WEPC116 | FERMI@Elettra Undulator Frame Study | 2276 |
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| The FERMI@Elettra project foresees installation of both linear (LPU) and elliptical polarization undulators (EPU). Following the girder study presented last year, a detailed design of the undulator frame has been now carried out. The aim of this work was to find out a mechanical structure that guarantees minimum displacement of the girders supporting the magnet arrays. At the same time the undulator overall dimensions have been taken into account and the mechanical structure mass minimized. In this paper topology optimization result, finite element simulation and multi-objective optimization analysis are presented. | ||
| WEPC117 | Influence of Insertion Devices on the ALBA Dynamic Aperture | 2279 |
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| Insertion devices can produce effects reducing the dynamic aperture in a storage ring. To study these effects for the ALBA light source the following insertion devices were inserted in the ALBA lattice: a superconducting wiggler SC-W31 with 31-mm-period and 2.1-T-field amplitude, and two Apple-II type PMM NdFeB undulators with periods of 62 mm (HU62) and 71 mm (HU71). Results of numerical study of the nonlinear beam dynamics by a 6D computer code are presented. | ||
| WEPC118 | Study of Controllable Polarization SASE FEL by a Crossed-planar Undulator | 2282 |
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| A potential and economical access to generate arbitrary polarized XFEL is to utilize crossed-undulator scheme instead of helical undulators. In this paper, the polarization of x-ray radiation for the European XFEL is investigated. The degree of polarization and the Stokes parameters are calculated for different configurations. The shot-to-shot fluctuation of polarization and the degree of polarization distribution over the transverse plane are also studied. | ||
| WEPC119 | First Year's Experience of Diamond Insertion Devices | 2285 |
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| Diamond was commissioned at 3GeV with seven insertion devices (IDs) already installed. The phase 1 IDs include five in-vacuum permanent magnet undulators, an APPLE–2 variable polarization device, and a superconducting wiggler. Since initial commissioning of the ring, three more in-vacuum undulators have been installed, and another three devices will be installed in the coming year. In this paper, we describe commissioning, characterizing, and operating with these IDs. | ||
| WEPC120 | An In Vacuum Wiggler WSV50 for Producing Hard X-rays at SOLEIL | 2288 |
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| SOLEIL is a medium energy storage ring (2.75 GeV) operating since 2006. The production of intense high energy photon beams requires insertion devices with high magnetic field and large number of periods. To cover the 20 keV-50 keV Photon Energy range, an in vacuum wiggler has been preferred to a superconducting wiggler. This choice results from a compromise between photon flux, investment and running cost. Deep studies have been performed to find the optimum magnetic field and period producing the maximum flux in the dedicated spectral range (20-50 keV). The wiggler is composed of 38 periods of 50 mm producing a 2.1 T magnetic field at a minimum gap of 5.5 mm. To minimize the high magnetic forces acting between the magnet arrays (10 tons), two compensation systems, composed of either springs or magnet blocks, have been designed. This paper presents the spectral performances of the wiggler compared with an optimized superconducting wiggler, the mechanical and magnetic design of the wiggler and the first tests of the compensation system. | ||
| WEPC121 | Magnetic Measurement Device for Superconductive Undulator Mock-up Coils at ANKA | 2291 |
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| A device for precise magnetic measurements of superconductive coils was designed, built and installed at the synchrotron radiation source ANKA, Forschungszentrum Karlsruhe. Accurate magnetic field measurements are a prerequisite for the characterization and optimization of insertion devices. The new device allows measuring the magnetic field magnitude of test coils with a longitudinal precision of 10 μm using a 2D Hall probe bench. The cylindrical liquid He cryostat allows mounting coils of maximum dimensions 50 cm in length and 30 cm in diameter. The set-up is computer controlled. The contribution will present the new device as well as the results obtained. | ||
| WEPC122 | Magnetic Characterization of an APPLE-II Undulator Prototype for FERMI@Elettra | 2294 |
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| The FERMI@Elettra free electron lasers will use APPLE-II undulators in the radiating sections to provide variably polarized photon beams. In preparation of the manufacturing of the final devices a prototype has been developed in order to test different methods of magnetic field optimization. For this purpose, an existing variable-gap support structure was equipped with a new mechanical interface providing the required longitudinal shifting of the magnetic arrays. Permanent magnet blocks were mounted on short modules and their field integrals measured using a stretched wire system. Field optimization was iteratively performed by proper selection of the modules to be mounted based on measurements of the partially assembled undulator structure. The results of the final magnetic field characterization are presented showing the achieved trajectory, phase and multipole errors. These results are compared with those of a previous assembly where the same modules were mounted in random order. Further improvements obtained by shimming and application of “magic fingers” are finally described. | ||
| WEPC124 | Magnetic Measurement System for the SPARC Insertion Devices | 2297 |
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| The characteristics and performances of the magnetic measurement system for the SPARC insertion devices are presented. A typical configuration formed by a a Hall probe mounted on a cart sliding on a granite beam was adopted to measure the properties of the six SPARC undulator sections. This approach has been adopted usually for rapid local field measurements. In this contribution we show that precision levels comparable to those of other well established techniques can be achieved also for critical issues like alignments, field integrals, phase errors etc. A new device purposedly designed to identify the reading area of the Hall probe with respect to bench coordinate system is presented and discussed. | ||
| WEPC125 | Development of Three New Superconducting Insertion Devices for the ANKA Storage Ring | 2300 |
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| After a first successful test of a superconductive cold bore undulator in ANKA a new generation of superconductive insertion devices is under construction or in a detailed planning phase. The first one, referred to as as SCU14 and now under construction, is an improved version of the existing undulator (14 mm period length, 100 periods long) with a new cooling scheme for small gap operation and a reduced field error. The period length of the second device called SCUW can be switched electrically between 15 and 45 mm. The third one is a superconductive undulator which can tolerate a beam heat load of several Watts in combination with a small field error named SCU2. It is designed for third generation light sources with a heat load of up to 6 Watt from the beam to the cold bore. | ||
| WEPC126 | On a Biscuit Current Undulator | 2303 |
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| A new undulator structure for free electron lasers was presented. Current BISCUIT devices produce magnetic fields which are spatially periodic. The current structure was in the shape of wires stacks . The current has alternating directions. The magnetic field components for each wire presents symmetry with two axis. The BISCUIT undulator transverse cross-section (in arbitrary units) is a function depending directly on cosine (for x component) and sine (for y component) and inverse on the square root of the sum of forth power of sine and cosine. The z component is a constant. The Biot - Savart law was numerically evaluated. The magnetic field is longitudinal and easily adjustable with the current. The versatility of the constant parameter covers longitudinal undulator or wiggler design for one or two beams devices with transverse momenta. | ||
| WEPC128 | SPUR: A New Code for the Calculation of Synchrotron Radiation from Very Long Undulator Systems | 2305 |
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| The accurate calculation of synchrotron radiation from an undulator is a common problem and numerous codes have been developed that describe analytic and measured fields. However, for very long undulator systems, comprising of many individual modules and total lengths in excess of 100s of meters, for example as found in the LCLS, X-FEL, the ILC positron source undulator systems, there is not a suitable code that can handle the amount of data in a convenient manner and which runs in a practically realisable time limit. The development of a new code, SPontaneous Undulator Radiation, SPUR, is presented which computes the spontaneous radiation from electron beams passing through a system of undulators. The code supports parallel architecture, and uses the HDF5 technology to efficiently handle the multi-dimensional data. The latest results developments and benchmarking are presented. | ||
| WEPC129 | Undulator Demagnetization due to Radiation Losses at FLASH | 2308 |
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| The free-electron laser FLASH was set up at DESY Hamburg in 2004. It is a high-gain, single pass FEL which operates in the VUV and soft X-ray wavelength regime. To monitor the demagnetization of the undulator structures due to radiation losses a small test undulator was installed. This dosimetric undulator (DU) consists of a short piece of magnetic undulator structure with only 3 pole pairs and corresponding magnets. It is positioned in front of the first undulator module where a high dose rate is to be expected. The accumulated dose of DU and undulator system is derived by weekly measurements with thermoluminescence dosimeters (TLDs). The DU is dismounted and magnetically measured regularly. Based on these measurements a (maximal) relative demagnetization rate of about 5*10-4/kGy was derived. In view of this result magnetic measurements on one of the undulators from TTF1 (the predecessor of FLASH) were reviewed. They show a relative demagnetization rate of about 2*10-4/kGy which is lower but still in the same range as the result from FLASH. FEL simulations to analyse the influence of the demagnetization on the SASE process are in progress. | ||
| WEPC130 | Shimming Correction of Dynamic Multipole Effects on Apple-II Type EPUs at the ALS | 2311 |
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| Elliptically Polarizing Undulators that provide full photon polarization control also have fast, intrinsic transverse roll-off of the magnetic field. The roll-off is particularly fast for vertical polarization settings, and can have big detrimental effects on the nonlinear single particle dynamics. Particularly low and medium energy light sources and long period EPUs are prone to those effects. The three existing 50mm period EPUs at the ALS have been retrofitted with shims to correct for these dynamic multipole effects and a new 90mm period device which otherwise would have caused a huge reduction in dynamic aperture has been shimmed before installation. Simulations and beam measurements will be presented, including frequency map measurements. | ||
| WEPC131 | Insertion Devices for NSLS-II Baseline and Future | 2314 |
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| NSLS-II is going to employ Damping Wigglers not only for emittance reduction but also as broadband hard X-ray source. In-Vacuum Undulators with minimum RMS phase error (< 2 degree) and possible cryo-capability are planned for X-ray planar device, and Elliptically Polarized Undulators are utilized for polarization controls. Due to lack of hard X-ray flux from weak dipole field (0.4 Tesla), three pole wigglers of peak field over 1 Tesla will be mainly used by NSLS bending magnet beam line users. Magnetic designs and kick maps for dynamic aperture surveys were created using the latest version of Radia for Mathematica 6 which we supported the development. There are other devices planned for later stage of the project, such as quasi-periodic EPU, superconducting wiggler/undulator, and Cryo-Permanent Magnet Undulator with Praseodymium Iron Boron (PrFeB) magnets and textured Dysprosium poles. For R&D, Hybrid PrFeB arrays were assembled and field measured at room temperature, liquid nitrogen and liquid helium temperature using our vertical test facility. We have also developed a specialized power supply for pulsed wire measurement. | ||
| WEPC132 | Damping Wigglers at the PETRA III Light Source | 2317 |
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| We report on the progress in construction of the PETRA III damping sections. A series of 10 permanent magnet wigglers followed by SR-absorbers will be installed in each of the two damping sections. Thereby, the emittance of the 6 GeV storage ring will be reduced down to 1 nmrad. Prototypes of all major components have meanwhile been characterized and a test assembly of one complete wiggler cell has been performed successfully. The wigglers have a period length of 200 mm and provide a peak field of 1.5 T. Most of the 4 m long devices have been fabricated and assembled. We present results of magnetic measurements and tuning. | ||
| WEPC133 | Status of the PETRA III Insertion Devices | 2320 |
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| The PETRA storage ring is presently reconstructed towards a third generation light source. In total, 14 undulator beamlines will be available in the new octant of the machine. We report on the status of Petra III undulators. Three prototypes with 29mm period length, two 2m and one 5m long device have been investigated by mechanical and magnetic measurements. The prototype results are the basis for the refined design of the remaining 8 planar devices which are in the procurement phase. We present preliminary magnetic results of the prototypes and also report on the APPLE–2 and the in-vacuum undulator for PETRA III. | ||
| WEPC135 | A New Concept for Reducing Phase Errors in Superconductive Undulators: Induction-shimming | 2323 |
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| Undulators are the most advanced sources for the generation of synchrotron radiation. The photons generated by a single electron add up coherently along the electron trajectory. In order to do so the oscillatory motion of the electron has to be in phase with the emitted photons along the whole undulator. Small magnetic errors can cause unwanted destructive interferences. In standard permanent magnet undulators the magnetic errors are reduced by applying shimming techniques. Superconductive undulators have higher magnetic fields than permanent magnet undulators but shimming is more complex. In this paper it is shown that coupled superconductive loops installed along the surface of the superconductive undulator coil can significantly reduce the destructive effect of the field errors. This new idea might allow the building of undulators with a superior field quality. | ||
| WEPC136 | Waveguide Structures for RF Undulators with Applications to FELs and Storage Rings | 2326 |
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| RF undulators, suggested long time ago, has the advantage of fast dynamic control of polarization, undulator strength and wavelength. However, RF undulators require very strong RF fields in order to produce radiation of the same order as conventional static devices. Very high power RF energy confined inside a waveguide or a cavity can provide the necessary RF fields to undulate the electron beam. However, the wall losses in the waveguide should be low enough to make it practically feasible as a CW or quasi CW undulator and, hence, competitive with static devices for applications to storage rings and FELs. Here we present various waveguide structures such as smooth walled and corrugated walled waveguides and various RF modes. We will show that there are some advantages in operating with higher order modes and also with hybrid modes in the corrugated guide. We will show that the RF power requirement for some of these modes will permit a quasi CW operation of the undulator, thus permitting its operation in a storage ring. | ||
| WEPC137 | Design of Two Variable Polarization Undulators for the ALBA Project | 2329 |
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| This paper summarizes the main aspects of the magnetic, mechanical and control system design of two APPLE-II type undulators presently under construction in the framework of a collaboration between CELLS and Sincrotrone Trieste. | ||
| WEPC138 | Transient Electromagnetic Analysis and Thermal Design on the Magnet of 3-GeV Synchrotron | 2332 |
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| J-PARC 3GeV synchrotron is operated at 25Hz alternatively, which can generate eddy currents and heat. They can disturb continuous operations. We prepared a design technique to analyze them and manage the temperature rises of the magnets. Eddy current and hysteresis heat generations were calculated with 3D models then temperature rises were evaluated with natural convection cooling from surfaces. The technique was applied on the dipole, quadrupole and bump magnets. Slits on intense eddy current position can decrease the heat generation, however deep slits can disturb magnetic field distribution. Their depth and positions were optimized for the temperature rise reduction. So far, the synchrotron operation is fair with reasonable temperature rises. | ||
| WEPC139 | Recent Experience in the Fabrication and Brazing of Ceramic Beam Tubes for Kicker Magnets at FNAL | 2335 |
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| Ceramic beam tubes are utilized in numerous kicker magnets in different accelerator rings at Fermi National Accelerator Laboratory. Kovar flanges are brazed onto each beam tube end, since kovar and high alumina ceramic have similar expansion curves. The tube, kovar flange, end piece, and braze foil (titanium/inconel) alloy brazing material are stacked in the furnace and then brazed in the furnace at 1000°C. The ceramic specified is Alumina 99.8% Al2O3, a strong recrystalized high-alumina fabricated by slip casting. Recent experience at Fermilab with the fabrication and brazing of these tubes has brought to light numerous problems including tube breakage and cracking and also the difficulty of brazing the tube to produce a leak-tight joint. These problems may be due to the ceramic quality, voids in the ceramic, thinness of the wall, and micro-cracks in the ends which make it difficult to braze because it cannot fill tiny surface cracks which are caused by grain pullout during the cutting process. Solutions which are being investigated include lapping the ends of the tubes before brazing to eliminate the micro-cracks and also metallization of the tubes. | ||
| WEPC141 | Septa and Distributor Developments for H- Injection into the Booster from Linac4 | 2338 |
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| The construction of Linac4 requires the modification of the existing injection system of the CERN PS Booster. A new transfer line will transport 160 MeV H- ions to this machine. A system of 5 pulsed magnets (BIDIS) and 3 vertical septa (BISMV) will distribute and inject the Linac pulses into the four-vertically separated Booster rings. Subsequently the beam will be injected horizontally, using a local bump created with bumpers (BS magnets) to bring the injected H- beam together with the orbiting proton beam onto the stripper foil. To accommodate the injected H- beam, the first of the BS magnets will have to be a septum like device, deflecting only the orbiting beam. This paper highlights the requirements and technical issues and describes the solutions to be adopted for both the BIDIS and BISMV. The results of initial prototype testing of the BIDIS magnet will also be presented. | ||
| WEPC142 | Design of Pulsed Magnets for the Taiwan Photon Source | 2341 |
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| A new Taiwan Photon source requires a high stability pulsed magnets for the top-up mode injection operation. We present a preliminary design of the pulsed magnets used for injection into the 3 GeV storage ring. A 0.6 m long kicker magnet prototype is fabricated for testing the field performance. The field testing results are described in this work. The septum magnet with a 0.4 mm thickness stainless steel vacuum chamber is real tested at 3 Hz operation. The field performance, the stray fields and the eddy current effect are presented in this paper. | ||
| WEPC143 | System for Local Magnetic Field Measurement System Based on a Coil with Three Square Millimeter | 2344 |
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| We present a magnetic field measurement system based on a rotating coil with 3mm2 active area and approximately 500 turns to measure local magnetic field. The structure of a coil is not so complex, simplifying the evaluation of its sources of errors. The steps used to build the coil are shown as well as the performance of the measurement system. The calibration of the coil was made against a magnetic field generated by a solenoid with very well determined geometry. | ||
| WEPC144 | Test Results of the AC Field Measurements of Fermilab Booster Corrector Magnets | 2347 |
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| Multi-element corrector magnets are being produced at Fermilab that will enable correction of orbits and tunes through the entire cycle of the Booster, not just at injection. The corrector package includes six different corrector elements - normal and skew orientations of dipole, quadrupole, and sextupole - each independently powered. The magnets have been tested during typical AC ramping cycles at 15Hz using a fixed coil system to measure the dynamic field strength and field quality. The fixed coil is comprised of an array of inductive pick-up coils around the perimeter of a cylinder which are sampled simultaneously at 100kHz with 24-bit ADC’s. The performance of the measurement system and a summary of the field results are presented and discussed. | ||
| WEPC145 | A Fast-sampling, Planar Array for Measuring the AC Field of Fermilab Pulsed Extraction Magnets | 2350 |
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| A system employing a planar array of inductive pick-up coils has been developed for measurements of the rapidly changing dipole field in pulsed extraction magnets of the Fermilab MuCool project. The magnets are of C-type design, and have a peak field of 0.65 T during 8.33 millisecond half-sine pulse with 15 Hz repetition rate. The coils of the measurement system are fabricated on a single, 97.5 mm wide, 2-layer circuit board. The top layer of the circuit board has 15 unbucked coils distributed over its width. The bottom layer has a similar arrangement of coils, except each is bucked against the central winding to suppress the main dipole field and allow for more sensitive measurements of higher-order harmonics across the magnet mid-plane. The array of coils is simultaneously sampled at data rates of up to 100kHz with 10kHz bandwidth using 24-bit ADC’s. A detailed overview of the system and data analysis is presented, along with a characterization of results and system performance. | ||
| WEPC146 | Plasma Lens of the ITEP Heavy Ion Accelerator | 2353 |
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At ITEP, on the bases of the TWAC-ITEP (Terawatt Accumulator) complex, a new facility is being built to conduct research at high energy densities in matter*. Application of a plasma lens to this area of research has a number of essential advantages in comparison with the traditional system based on quadruple lenses**. In accordance with the principal goals of this project, a pulse-power generator has been developed, with which a stable discharge current of up to 250 kA and duration of 4 μs has been achieved and which was used for experimental and theoretical investigation of the plasma lens performance. The plasma lens was installed into the exit channel of the TWAC accelerator complex, and its testing began by focusing of a C+6 beam with the ion energy of 200 MeV/a.u.m. As one of the first results, a minimum focal spot diameter of 350 μm FWHM has been measured at a target distance of 50 mm from the end of the discharge tube. The lens parameters were as follows: capacitance – 24 μF, charging voltage – 13 kV, discharge current – 220 kA, current half-wave – 4 μs, argon pressure – 3 mbar.
*Sharkov B. Yu. et al. Nucl. Instr. Meth. A464 (2001), p. 1. |
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| WEPC150 | Fast Local Bump System for Helicity Switching at the Photon Factory | 2356 |
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| Two APPLE-II type variably polarizing undulators will be installed at the south straight section of the PF (Photon Factory) ring. The 10Hz fast orbit switching in these undulators will be conducted for the helicity switching. The required angular difference of the orbits in two undulators is 0.3mrad. The five identical bump magnets and AC power supplies are manufactured to make 10Hz time varying local bumps. In order to achieve the local bump and prevent the fluctuation of the beam orbit with the effects of the insertion devices and magnetic errors, the feed forward correction with the bump magnets and the feedback correction with the fast steering magnets are required. In this presentation, the measurement results of the magnetic field and the frequency response, the configuration of the control system, and the simulation results to achieve the local bumps are shown. | ||
| WEPC151 | Magnetic Field Design and Calculation for the FLNR U400R Cyclotron | 2359 |
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| Presently FLNR reconstructs the U400 cyclotron. The new, U400R cyclotron is intended to accelerate the ion beams with A/Z from 4 to 12 up to the energy 0.78 – 27 MeV/nucleon. The wide range of the magnetic field levels from 0.8T till 1.8T allows to make a smooth variation of the beam energy over the range ±60% from nominal. For optimization of the magnetic field the 14 pairs of radial correcting coils are used. The numerical formation of the magnetic field is carried out. At the present work the main problems and solutions of the magnetic field design are described. | ||
| WEPC152 | Magnet Block Optimization of the APPLE-II Elliptically Polarized Undulator | 2362 |
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| The uniform field region of elliptically polarized undulator (EPU) of APPLE-II type is very short especially in the horizonta axis. The magnet block arrangements with a approximately parabolic pole face or of APPLE-II undulator can enlarge the horizontal field roll-off and shorten the vertical field roll-off. We studied the dfferent shapes to expect a optimizaed horizotal and vertical field roll-off. | ||
| WEPC153 | Dipole Magnet for Use of RHIC EBIS HEBT Line | 2365 |
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| We present the design optimization of a dipole magnet for use of RHIC EBIS HEBT line. This magnet provides a total bending angle of 145 degrees by two identical magnets and it is used to guide H+ to Au32+ beam with energy of 2 MeV/amu. Magnetic field is required to change within 1 second corresponding to the ion species, so magnet body has the laminated structure to suppress eddy current. Effective length and field quality within a radius of 5 cm was optimized separately. Effective length was optimized by adjusting end shape not to change the beam orbit between low and high field operation more than 1 mm from intended beam orbit after bending. Then field quality was optimized by changing the shim position and additional bump. After modification, all multipole coefficients along the beam trajectory were reduced to within 10x10-4. | ||
| WEPC154 | Design and Fabrication of Multipole Corrector Magnet | 2368 |
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| The Taiwan Light Source (TLS) had started to operate in top-up mode injection since October 2005. Meanwhile, the Elliptically Polarized Undulator (EPU5.6) was operated very well in the decay mode operation. However, the partial beam loss had occurred when the top-up injection was executed at magnet gap and magnet array phase are fixed at the minimum gap and π(vertical polarization mode), respectively. In order to solve the partial beam loss, we design a new multipole corrector magnet to be installed in the downstream of the EPU5.6 to compensate for the multipole field error. This multipole magnet can provide the normal and skew components of the dipole, quadrupole, sextupole, octople, and dodecapole field components. Changeable multipole field components mechanism has been designed by using a special electric circuit. In addition, the measurement systems of Hall probe and stretch wire are used to measure the field quality of the multipole corrector magnet. This report will discuss the magnet circuit design, mechanical design, the switching mechanism of the multipole field components, and the field measurement results. | ||
| WEPC155 | Experimental Characterization of Permanent Magnet Harmonic Corrector Rings | 2371 |
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| A total of three permanent magnet chicane magnets have been installed at the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory. The magnet design incorporates counter-rotating permanent magnet pairs with trim coils. The purpose is to provide a fixed angular separation between two successive elliptically polarizing undulator (EPU) photon fans and to correct steering perturbation resulting from EPU polarization state and gap changes. This paper presents a method for the determination of the permanent magnets parameters and setting relative orientations of the rotors by performing magnetic measurements with rotating coils. The measurement method will be developed and illustrated with experimental data from the measurement of a 16 cylinder permanent magnet harmonic corrector ring. | ||
| WEPC156 | Development and Adjustment of the EMMA Quadrupole Magnets | 2374 |
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The non-scaling FFAG EMMA, now under construction at STFC’s Daresbury Laboratory, requires 84 quadrupoles. Because of the unusual nature of these magnets*, prototypes for the F and the D type quadrupoles were required. These magnets were ordered from and constructed and measured by Tesla Engineering. Subsequently, design changes have been made and modifications to the prototypes carried out. The paper will give engineering details of these prototypes, of the measurement results obtained using a rotating coil magnetometer and subsequent adjustments to clamp plates and pole profiles needed to obtain optimum three dimensional gradient quality. As a result of these developments, the construction of the magnets for the complete ring is now underway.
*B. J.A. Shepherd & N. Marks, “Quadrupole Magnets For The 20MeV FFAG, ‘EMMA’”, PAC 2007 (MOPAN107). |
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| WEPC157 | A Hybrid Quadrupole Design for the RAL Front End Test Stand (FETS) | 2377 |
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| The Front End Test Stand project being constructed at Rutherford Appleton Laboratory (RAL) aims to deliver a high current (60 mA) H- chopped ion beam, at 3 MeV and 50 pps. The main components of FETS are the H- ion source, the Low Energy Beam Transport line (LEBT), the Radio Frequency Quadrupole (RFQ) and the Medium Energy Transport (MEBT) line with beam chopper. Space restrictions in the MEBT line place constraints on component length and drive the requirement to identify compact component configurations. A description is given of a novel compact hybrid quadrupole magnet, whose design is based on the concentric combination of a permanent magnet quadrupole (PMQ) and a laminar conductor electromagnetic quadrupole (EMQ). Simulations of magnetic field distribution in 2 and 3D are presented, and possible applications and further developments are discussed. | ||
| WEPC159 | Compact Design of Race-track Microtron Magnets | 2380 |
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| A novel design of the end magnets for race-track microtrons (RTMs) is proposed. It consists of four-poles with the REPM material being used as a source of the magnetic field. For a proper choice of parameters of such magnetic system it can provide both the closure of the first orbit after beam reflection and required focusing properties. It is shown that such end magnet can be made quite compact thus allowing to build miniature RTMs. The procedure of design of the four-pole magnetic system and its optimization using the ANSYS code is described in detail. | ||
| WEPC160 | Eddy-current Effect on Field Multipoles Arising in Dipole Magnets with Elliptic and Rectangular Beam Pipe | 2383 |
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| We present an analytical evaluation of the field-distortion effect from eddy currents induced by variation of magnetic field of dipole magnets with elliptic or rectangular beam pipe of finite conductivity. The pipe sizes and aspect are arbitrary except that for practical reasons we assume the pipe wall thickness is small as compared to the skin depth. Handy formulas are presented for the field multipoles arising from non-round shape of the beam pipe. | ||
| WEPC161 | Some Remarks about Characterization of Magnetic Blocks with Helmholtz Coil | 2386 |
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| The use of Helmholtz coils for magnetic block characterization is a widespread technique because of its small sensitivity to block positioning errors and high precision. In this paper we present some calculations related to the influence of block positioning for the cases where the Helmholtz condition is not exactly satisfied. Also the comparison between a model based on point dipolar magnetic moment and magnetized blocks with real dimensions is analyzed, as well as the corrections associated to the effect of self-demagnetization of the blocks. | ||
| WEPC163 | Modification of a Spare Septum Magnet for SNS Ring Injection Dump Beam Line | 2389 |
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| The SNS ring injection dump septum magnet has been suffering the heaviest beam losses since the ring commissioning. These beam losses are caused by a number of design and operation problems such as incorrect location of one chicane dipole, incorrect chicane dipole setting, and inadequate aperture of the injection dump septum. We have modified a spare septum by increasing its vertical and horizontal aperture and by adding specially designed z-bumps for one of the waste beams. This paper reports the detailed modification results, including 3D particle trajectory calculations and experimental measurements. | ||
| WEPC164 | Development of Modulating Permanent Magnet Sextupole Lens for Focusing of Cold Neutrons | 2392 |
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| A modulating permanent magnet sextupole lens that can focus pulsed cold neutrons is under development. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to adjust the strength, the magnet is divided into two co-axial nested rings, where the inner ring is fixed and the outer ring can be rotated. Synchronizing the period of the modulation with that of pulsed neutron beam suppress the chromatic aberration. We have fabricated a half-scale model and studied the strength, the torque and the temperature rise caused by eddy current. Now we are developing the full-scale model improving such problems. These two scale models of magnet are described. | ||
| WEPC165 | Magnetic Measurements of the SSRF Storage Ring Magnets | 2395 |
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| The SSRF storage ring comprises a total of 460 magnets which has four types and eight different effective magnetic lengths. The magnetic measurements of all the production magnets including 40 bending magnets with a maximum field of 1.2726 T, 200 quadrupoles divided in Three families with a maximum gradient of 20 T/m, 140 sextupoles with a maximum second order differential of 460 T/m, and 80 correctors with a maximum kick capability of 1.2 mrad. For the dipoles a long coil system has been used to measure the magnetic field while for the quadrupoles and sextupoles a rotating coil system has been used to determine the magnitude of the high order multipoles. In this paper the analysis of these data is discussed and results for measured magnets are presented. |