| Paper | Title | Page |
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| TUPD032 | Single Bunch Wakefields in the CERN-PSI-ELETTRA X-band Linear Accelerator | 1997 |
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FERMI@ELETTRA and PSI-XFEL are 4th Generation Light Sources that require high quality electron beam at the entrance of the undulator chains. In this context, a specially developed X-band structure with integrated alignment monitors will be used to mitigate the nonlinearities in the longitudinal phase space due to the second order RF time curvature and the second order momentum compaction term of chicane compressor. The knowledge of the transverse and longitudinal short range wakefields in the X-band structure is essential to evaluate the beam quality in terms of longitudinal energy spread and transverse kick spread. We have used the ABCI code to numerically evaluate the transverse and longitudinal wake potentials for short bunches in this structure. |
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| TUPD033 | Short Range Wakefields Studies of Step-out and Taper-out Transitions Adjacent to X-band Linac in FERMI@elettra | 2000 |
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FERMI@ELETTRA is a single pass FEL Facility in construction at the ELETTRA Laboratory in Trieste. To linearize the beam longitudinal phase space, it is planned to use a short X-band accelerating structure installed before the first bunch compressor. Since both the end tubes of the structure have a reduced radius of 5.0 mm, much smaller than the 13.5 mm radius of the beam pipes before and after the structure, a transition, either stepped or tapered, will be necessary between the two components. Using the ABCI code, we have investigated the short range wake fields at the step-out and taper-out transitions and we have compared them with some conventional analytical models. We have developed specific ABCI-based analytical models that simulate accurately the short range wake field for a wide range of rms bunch lengths (σ: 100 - 1000μm). |
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| TUPD034 | The Short Range Wakefields of the Traveling Wave and Standing Wave X-band Linearizer of FERMI@ELETTRA FEL: A Comparative Study | 2003 |
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In most of the Linac based 4th Generation Light Sources now under development (e.g. FERMI@ELETTRA [1]), a short accelerating structure operating at higher harmonics (i.e. X-band, 12 GHz), is adopted to linearize the beam's longitudinal phase space [2]. This structure could be either travelling wave (TW) or standing wave (SW) type. As it is well known, each one of such structures has its own advantages and drawbacks in terms of RF properties but there is a lack of information about the wake fields of each type compared to the other. In this paper an overall comparison, from the wakefields point of view, of two different X-band structures will be carried out. The purpose is to evaluate quantitatively the longitudinal and transverse wake functions of the structures, determining their relevant wake integrals, such as the average value of energy loss, rms energy spread, kick factor and kick spread. |
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| TUPD035 | ABCI-based Analytical Model for Calculating the Transverse Kick Factor in Axi-symmetric Step-out Transition | 2006 |
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Step-out transition is one of the most frequent component, commonly used on the new generation light source facilities where very short and dense electron bunches are considered. The numerical calculation of the short-range wake at this type of transition requires a spatial mesh size equal to a fraction of bunch length. This calculation becomes for a very short bunch, e.g. σ = 25μm, very time consuming due to the large number of mesh points required. On the other hand, the available analytical models that calculate the transverse wake field are applicable only on a narrow range of bunch lengths. We developed an ABCI-based analytical model that can calculate accurately the kick factor. The advantage of this model is quick, accurate and covers wide range of rms bunch lengths (up to σ = 1000μm). The model also covers a wide range of beam pipe ratio b/a. |
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| TUPE015 | The X-band System for the FERMI@ELETTRA FEL Project | 2173 |
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The single pass FEL facility FERMI@ELETTRA, in construction at the ELETTRA Synchrotron Radiation Laboratory in Trieste, requires very short electron bunches with a very high beam quality at the entrance of the undulator chain. To linearize the longitudinal phase space before the bunch compression, mitigating the effects of Coherent Synchrotron Radiation (CSR), a 4th harmonic accelerating section (12 GHz) will be installed before the first magnetic chicane. Here an overall description of the X-band system under development is reported. |
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| THPE064 | Electron Beam Dynamics in CERN-PSI-ELETTRA 5π/6 Traveling Wave X-band Linear Accelerator. | 4662 |
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The 4th Generation Light Source FERMI@ELETTRA, in construction at the ELETTRA Laboratory in Trieste, requires very short electron bunches at the entrance of the undulator chain. To linearize the longitudinal phase space in the presence of the compression process, a 4th harmonic decelerating section (11992 MHz) will be installed before the first magnetic chicane. An X-band structure, with integrated alignment monitors [1], is currently under development in the framework of collaboration between CERN-PSI-ELETTRA. In this paper we will present a full longitudinal and transversal beam dynamics of the electron beam along the X-band structure during linearization process using 3D space charge code TStep [2]. Beam dynamics simulations will also be continued along the whole FERMI linac using elegant code [3]. |