| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| MOPO031 | Alignment of theTPS Front-End Prototype | alignment, laser, synchrotron, survey | 550 |
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| The Taiwan Photon Source (TPS) is a 3-GeV third-generation source of synchrotron radiation with beam current 500 mA stored in the storage ring. A front end allows intense synchrotron light generated in the storage ring to pass through to a beamline. Most heat load of the synchrotron light is removed in the front ends to protect the beamline components. Alignment of front-end components becomes important to prevent damage from the large heat load. Because of the many front ends and the brief period of installation, the alignment work should be easy, quick and reliable. Using a shim method, the adjustable degrees of freedom are decreased from six to two. This adjustment work becomes easier and quicker. The alignment of a front-end prototype is described here. | |||
| MOPS048 | Microbunching Instability Studies at SOLEIL | electron, radiation, storage-ring, synchrotron | 709 |
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| Microbunching instability arises in storage rings when the number of electrons in a bunch exceeds a threshold value. Its signature, i.e. a strong and irregular emission of Coherent Synchrotron Radiation (CSR) in the Terahertz (THz) domain, is studied at SOLEIL on the AILES infrared beamline, with the storage ring tuned in a low-alpha configuration (used to get shorter electron bunch). The comparison of this observed THz CSR with numerical simulations of the longitudinal electron bunch dynamics, permits to put in evidence that during the instability a modulation appears and drifts in the longitudinal profile of the electron bunch. The understanding of this instability is important as it limits some operation of the storage rings. Indeed the induced fluctuations prevent the use of THz on the far IR beamline at high current per bunch. And in normal alpha operation this instability may spoil the electron/laser interaction effects used to get femtosecond and/or coherent pulse in storage rings (with slicing, Coherent Harmonic Generation or EEHG schemes on storage ring). | |||
| TUPC093 | CSR Bunch Length Monitor for XFEL/SPring-8 - SACLA | radiation, FEL, electron, synchrotron | 1224 |
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| SPring-8 Angstrom Compact Free Electron Laser (SACLA) is now under commissioning operation, aimed at the generation of a sub-angstrom free electron laser (FEL). In order to ensure the stable FEL generation, non-distractive bunch length monitors utilizing coherent synchrotron radiation (CSR) are installed. The monitors are located at the downstream of individual bunch compressor (BC1-BC3), and they measure the radiation emitted at the individual last magnets of the chicanes. At the magnets, beams with bunch lengths form 10 fs to 1000 fs generate the CSRs with a spectrum ranging the almost whole infrared region (0.03 - 3 THz). The CSRs are detected by a Schottky diode at the BC1, or pyroelectric detectors and a simple organic lens optical system at BC2 and 3. The bunch length monitor systems are used for bunch length feedback control to obtain the stable lasing by changing the rf parameter of acceleration cavities before the BCs. A preliminary system for the above mentioned system was tested at the SCSS test accelerator, and it showed sufficient performance to measure bunch length up to 300 fs. In this report, we describe the design and the results of the first operation. | |||
| TUPC146 | Beam Profiles Analysis for Beam Diagnostic Applications | background, synchrotron, diagnostics, instrumentation | 1368 |
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| Beam profile and its analysis play an important role in beam diagnostics of a particle accelerator system. Use of destructive screen monitor or non-destructive synchrotron radiation monitor for beam profile measurement is a simple way and has been widely used in synchrotron light source facility. Analyze beam profiles can obtain beam parameters including beam center, σ, and tilt angle which has become a useful tool for beam diagnostic. In this report the comparison of fitting strategies affect the analysis results are studied. The computer simulated beam profiles with different background noise level and conditions are used to evaluate the computing time, and the estimated fitting errors. | |||
| TUPO007 | FLUTE, a Linac Based THz Source | radiation, linac, gun, synchrotron | 1458 |
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| We propose a versatile THz source named FLUTE (“Ferninfrarot Linac- Und Test-Experiment”) based on a 30 - 50 MeV S-band linac with bunch compressor, that shall not only provide high field THz pulses applications but shall also serve as a test facility to study important accelerator physics issues. This is also of importance in view of the planned utltra-broadband THz to mid infrared user facility TBONE. Special emphasis is put on studies of bunch compression and beam stability as a function of bunch charge (0.1-5 nC) and of different generation mechanisms of coherent radiation (CSR, CER, CTR). This paper describes the design and layout of the proposed FLUTE machine and presents results of beam dynamic calculations with the tracking programs ASTRA and CSRtrack. | |||
| TUPO010 | An Innovative Lattice Design for a Compact Storage Ring | lattice, radiation, storage-ring, synchrotron | 1467 |
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Funding: *This work is partially supported by Cooperative and Supporting Program for Researches and Educations in Universities sponsored by KEK. We propose a new concept of lattice design for a compact light source storage ring. In a ring with this new scheme, the electron beam may have extremely longer design orbit than that of a conventional ring. In this ring, a design orbit closes after completing multiple turns. The lattice for realizing this exotic beam orbit can be made by placing conventional accelerator components such as bending magnets, quadrupole magnets, RF cavity and so forth in an appropriate manner onto a projected torus knot in the horizontal orbit plane. Due to an extended closed orbit length, the ring with this type of lattice has larger maximum stored charge if operated in multiple-bunch mode, and has longer bunch-to-bunch interval if operated in a single-bunch mode. Also, essential for a storage ring as the synchrotron light source, a larger number of straight sections may accommodate with many insertion devices. In addition, this new scheme may provide advantages for designing a oscillator-type free electron laser and coherent radiation light source. |
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| TUPS002 | Photodesorption Measurements at ESRF D31 | vacuum, radiation, synchrotron, electron | 1518 |
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| Since 1998 exists at ESRF a dedicated beamline for photodesorption measurement from vacuum chambers - D31. The original goal of this installation was to study the wall pumping effect. When exposed to synchrotron radiation surfaces exhibit strong outgassing of the adsorbed gas layer despite UHV conditions. Long term outgassing leads to the depletion of the adsorbed layer and produces a very clean surface which turns the walls of the vacuum chamber into an active pumping surface. The desorption mechanisms can be described by the long standing models of Knotek-Feibelman (KF) and Menzel-Gomer-Redhead – (MGR) which are themselves encompassed under the name of Desorption Induced by Electronic Transitions (DIET). In these models the surface itself plays a fundamental role in the desorption mechanism. At D31 have been tested chambers of stainless steel, aluminum and copper, with or without coatings (e.g. NEG, copper), designed by ESRF and other institutes like ALBA, CERN, ELETTRA and Soleil. Here we review some of the results obtained and outline the future plans of D31. | |||
| TUPS009 | SEY of Al Samples from the Dipole Chamber of PETRA III at DESY | electron, emittance, simulation, synchrotron | 1533 |
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| At the synchrotron radiation facility PETRA III, tune spectra have been measured with some characteristics which are typically observed at other storage rings in connection with electron cloud effects. For some bunch filling patterns, an increase of the vertical emittance has been observed. To estimate such effects with the available e-cloud simulation codes, the detailed knowledge of the SEY (Secondary Electron Yield) of the Al chamber, is required. To the purpose, representative PETRA III Al samples, were studied in detail at the INFN-LNF Surface Science Laboratory. XPS (X-ray photoelectron spectroscopy) and SEY measurements were performed as a function of electron and argon ion conditioning. The SEY of the as received samples shows a maximum value of δmax ≅ 2.8. Electron conditioning at 500 eV kinetic energy, reduces the SEY to values between δmax ≅ 1.8 to 1.4 (depending on the actual sample analyzed). The XPS characterization of the sample surface, after several cycles of argon ion sputtering, shows clearly that the SEY variation is closely related to the oxidation state of the Al sample, reaching a δmax value as low as 1.3 for our cleanest surface. | |||
| TUPS063 | Power Saving Schemes in the NSRRC | controls, synchrotron, status, radiation | 1680 |
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| National Synchrotron Radiation Research Center (NSRRC), Taiwan will complete the construction of the civil and utility system engineering of the Taiwan Photon Source (TPS) in the end of 2012. The power consumption of the TPS is estimated about 2.3 times of that of the existed Taiwan Light Source (TLS). To cope with increasing power requirement in the near future, we have been conducting several power saving schemes, which include power requirement control, optimization of chillers operation, application of heat pump, air conditioning system improvement, power factor improvement and the lighting system improvement. | |||
| THPC013 | THz Studies at a Dedicated Beamline at the MLS | radiation, electron, synchrotron, storage-ring | 2933 |
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The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute is operating the low-energy electron storage ring Metrology Light Source (MLS) in Berlin-Adlershof in close cooperation with the Helmholtz-Zentrum Berlin. The MLS is designed and prepared for a special machine optics mode (low-alpha operation mode) based on a sextupole and octupole correction scheme, for the production of coherent synchrotron radiation in the THz region*. At the MLS two bending magnet beamlines dedicated to the use of IR and THz synchrotron radiation are in operation: the MLS-IR beamline optimized for the NIR to FIR, and a dedicated THz beamline optimized for the FIR/THz spectral range**. Low-alpha operation optic modes for different ring energies, 250 MeV, 350 MeV, 450 MeV and 630 MeV are available. We compare the THz spectra taken in the different low-alpha modes and discuss the results.
* J. Feikes et al., Phys. Rev. ST Accel. Beams 14, 030705 (2011). ** R. Müller et al., J. Infrared Milli Terahz Waves, in press (2011), DOI: 10.1007/s10762-011-9785-6. |
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