| Paper |
Title |
Page |
| MOPKF041 |
SPARC Photoinjector Working Point Optimization, Tolerances and Sensitivity to Errors
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396 |
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- M. Ferrario, M.E. Biagini, M. Boscolo, V. Fusco, S. Guiducci, M. Migliorati, C. Sanelli, F. Tazzioli, C. Vaccarezza
INFN/LNF, Frascati (Roma)
- L. Giannessi, L. Mezi, M. Quattromini, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma)
- J. Rosenzweig
UCLA, Los Angeles, California
- L. Serafini
INFN-Milano, Milano
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A new optimization of the SPARC photoinjector, aiming to reduce the FEL saturation length, is presented in this paper. Start to end simulations show that with 1.1 nC charge in a 10 ps long bunch we can deliver at the undulator entrance a beam having 100 A in 50% of the slices (each slice being 300 mm long) with a slice emittance £1 mm, thus reducing the FEL-SASE saturation length to 12 m at 500 nm wavelength. In addition the stability of the nominal working point and its sensitivity to various type of random errors, under realistic conditions of the SPARC photoinjector operation, are discussed. A systematic scan of the main parameters around the operating point, performed with PARMELA code interfaced to MATLAB, shows that the probability to get a projected emittance exceeding 1 mm is only 10 % and the slice emittance remains below 1 mm in all cases.
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| MOPKF042 |
Status of the SPARC Project
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399 |
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- M. Ferrario, D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, L. Pellegrino, M.A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario
INFN/LNF, Frascati (Roma)
- F. Alessandria, A. Bacci, M. Mauri
INFN/LASA, Segrate (MI)
- I. Boscolo, F. Brogli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, M. Romé, L. Serafini
INFN-Milano, Milano
- L. Catani, E.C. Chiadroni, A. Cianchi, S. Tazzari
Università di Roma II Tor Vergata, Roma
- F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, L. Mezi, P.L. Ottaviani, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma)
- D. Dowell, P. Emma, C. Limborg-Deprey, D. Palmer
SLAC, Menlo Park, California
- D. Levi, M. Mattioli, G. Medici
Università di Roma I La Sapienza, Roma
- M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma
- P. Musumeci, J. Rosenzweig
UCLA, Los Angeles, California
- M. Nisoli, S. Stagira, S. de Silvestri
Politecnico/Milano, Milano
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The aim of the SPARC project is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments at 500 nm and higher harmonics generation. It has been proposed by a collaboration among ENEA-INFN-CNR-Universita‘ di Roma Tor Vergata-INFM-ST and funded by the Italian Government with a 3 year time schedule. The machine will be installed at LNF, inside an existing underground bunker. It is comprised of an rf gun driven by a Ti:Sa laser to produce 10-ps flat top pulses on the photocathode, injecting into three SLAC accelerating sections. We foresee conducting investigations on the emittance correction and on the rf compression techniques up to kA level. The SPARC photoinjector can be used also to investigate beam physics issues like surface-roughness-induced wake fields, bunch-length measurements in the sub-ps range, emittance degradation in magnetic compressors due to CSR. We present in this paper the status of the design activities of the injector and of the undulator. The first test on diagnostic prototypes and the first experimental achievements of the flat top laser pulse production are also discussed.
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| MOPKF043 |
An Ultra-high Brightness, High Duty Factor, Superconducting RF Photoinjector
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402 |
| |
- M. Ferrario
INFN/LNF, Frascati (Roma)
- J. Rosenzweig
UCLA, Los Angeles, California
- J. Sekutowicz
DESY, Hamburg
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Recent advances in superconducting rf technology, and an improved understanding of rf photoinjector design optimization make if possible to propose a specific design for a superconducting rf gun which can simultaneously produce both ultra-high peak brightness, and high average current. Such a device may prove to be a critical component of next generation x-ray sources such as self-amplified spontaneous emission free-electron lasers (SASE FEL) and energy recovery linac (ERL) based systems. The design presented is scaled from the present state-of-the-art normal conducting rf photoinjector that has been studied in the context of the LCLS SASE FEL. Issues specific to the superconducing rf photoinjector, such as accelerating gradient limit, rf cavity design, and compatibility with magnetic focusing and laser excitation of a photocathode, are discussed.
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| MOPKF044 |
Wake Fields Effects in the Photoinjector of the SPARC Project
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405 |
| |
- V. Fusco, M. Ferrario, B. Spataro
INFN/LNF, Frascati (Roma)
- M. Migliorati, L. Palumbo
Rome University La Sapienza, Roma
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When a bunch travels off axis across structures whose shape is not uniform, such as RF cavity or bellows, generates longitudinal and transverse wake fields. In addition transverse time dependent fields (like transverse RF components and wake fields ) may induce correlated slice centroids displacement, so that each slice centroid motion become affected also by space charge forces generated by the next slices. An evaluation of the emittance degradation and induced energy spread in the SPARC injector is performed with an improved version of the code Homdyn and the results are discussed. A comparison with other codes (ABCI, PARMELA 3D) to validate our model is also presented.
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| MOPLT062 |
The Design of a Prototype RF Compressor for High Brightness Electron Beams
|
698 |
| |
- D. Giove, F. Alessandria, A. Bacci, C. De Martinis, M. Mauri
INFN/LASA, Segrate (MI)
- D. Alesini, M. Ferrario, A. Gallo, F. Marcellini
INFN/LNF, Frascati (Roma)
- L. Serafini
INFN-Milano, Milano
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The generation of sub-ps electron bunches with low transverse emittance at nC charge level is a crucial requirement in the design of injectors for short wavelength FEL's. The technique of velocity bunching has been by now experimentally proven in various laboratories, where bunches below the ps bunch length were obtained: however, preservation of a low transverse emittance after the bunch compression is still to be demonstrated. To this aim, the use a slow wave RF structure as a rectilinear compressor has been proposed in the past to overcome the inherent difficulties of magnetic compressors. In this paper we will review the work carried out in the last 2 years and focused on the design a RF compressor based on a 3 GHz slow-wave copper structure. The rationale of the conceptual design along with a description of the main experimental activities will be presented and the future application of such a scheme to the SPARC project will be discussed.
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| THPLT059 |
Design Study of a Movable Emittance Meter Device for the SPARC Photoinjector
|
2619 |
| |
- A. Cianchi, L. Catani
INFN-Roma II, Roma
- M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, M. Ferrario, D. Filippetto, V. Fusco
INFN/LNF, Frascati (Roma)
- L. Giannessi, L. Picardi, M. Quattromini, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma)
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Preliminary studies of the SPARC rf gun are planned to obtain an accurate analysis and optimization of the emittance compensation scheme, measuring the beam emittance evolution downstream the RF gun with an appropriate diagnostic system. Since with a space charge dominated beam the use of the quad-scan method is not possible a 1D pepper-pot method will be used. A mask with narrow slits will be mounted on a movable support, spanning a 1.5 m meters region to measure the emittance in several positions and reconstruct its behavior in the post gun section. Numerical simulations of the measurement process, mainly based on PARMELA and TREDI, are used to estimate the achievable accuracy and to optimize the experimental setup. Wake field effects induced by the beam propagation through the long bellows have been also investigated with HOMDYN. Based on these simulations the design of the apparatus, called emittance-meter, has been realized and is under construction at LNF.
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| MOPLT061 |
Design Study for Advanced Acceleration Experiments and Monochromatic X-ray Production @ SPARC
|
695 |
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- L. Serafini, S. Cialdi, R. Pozzoli, M. Romé
INFN-Milano, Milano
- D. Alesini, S. Bertolucci, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, M. Migliorati, C. Milardi, L. Palumbo, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario, M. Zobov
INFN/LNF, Frascati (Roma)
- F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri
INFN/LASA, Segrate (MI)
- R. Bonifacio, I. Boscolo, C. Maroli, V. Petrillo, N. Piovella
Universita' degli Studi di Milano, MILANO
- A. Mostacci
Rome University La Sapienza, Roma
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We present a design study for an upgrade of the SPARC photo-injector system, whose main aim is the construction of an advanced beam test facility for conducting experiments on high gradient plasma acceleration and for the generation of monochromatic X-ray beams to be used in advanced medical applications and condensed matter physics studies. Main components of the proposed plan of upgrade are: two additional beam lines with interaction regions for synchronized high brightness electron and high intensity photon beams and the upgrade of the SPARC Ti:Sa laser system to reach a multi-TW power level (in excess of 1 J in pulse energy). Results of numerical simulations modeling the interaction of the SPARC electron beam and the counter-propagating laser beam are presented with detailed discussion of the monochromatic X-ray beam spectra generated by Compton backscattering: X-ray energies are tunable in the range 20 to 500 keV, with pulse duration from sub-ps to 30 ps. Preliminary simulations of plasma acceleration of the SPARC electron beam, generated in ultra-short bunches, via the LWF mechanism and with external injection are also shown: experiments of self-injection are also foreseen and illustrated.
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