IPAC2011 - List of Authors (Mostacci, A.)

Paper

Title

Page

Advanced Beam Manipulation Techniques at SPARC

2877

A. Mostacci, D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, M. Castellano, E. Chiadroni, G. Di Pirro, A. Drago, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
B. Marchetti
INFN-Roma II, Roma, Italy
M. Migliorati
University of Rome "La Sapienza", Rome, Italy
L. Palumbo
Rome University La Sapienza, Roma, Italy
V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

SPARC in Frascati is a high brightness photo-injector used to drive Free Electron Laser experiments and explore advanced beam manipulation techniques. The R&D effort made for the optimization of the beam parameters will be presented here, together with the major experimental results achieved. In particular, we will focus on the generation of sub-picosecond, high brightness electron bunch trains via velocity bunching technique (the so called comb beam). Such bunch trains can be used to drive tunable and narrow band THz sources, FELs and plasma wake field accelerators.

Slides THYB01 [20.772 MB]

THPC100

Full Temporal Reconstruction using an Advanced Longitudinal Diagnostic at the SPARC FEL

3119

G. Marcus, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, V. Surrenti
ENEA C.R. Frascati, Frascati (Roma), Italy
A. Bacci, M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci, A.R. Rossi
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano, Italy
J.V. Rau
ISM-CNR, Rome, Italy

The Production of ultra-short (sub 100 fs) single-spike radiation possessing full longitudinal coherence from a free-electron laser (FEL) has been the subject of intense study. A Frequency-Resolved Optical Gating (FROG) diagnostic has been developed and tested at UCLA, which has the capability of providing a longitudinal reconstruction of these ultra-fast pulses. This paper reports the results of the application of the diagnostic at the SPARC FEL facility.

THPC159

Factory Acceptance Test of COLDDIAG: A Cold Vacuum Chamber for Diagnostics

3263

S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
V. Baglin
CERN, Geneva, Switzerland
C. Boffo, G. Sikler
BNG, Würzburg, Germany
T.W. Bradshaw
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
R. Cimino, M. Commisso, A. Mostacci, B. Spataro
INFN/LNF, Frascati (Roma), Italy
J.A. Clarke, R.M. Jones, D.J. Scott
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.P. Cox, J.C. Schouten
Diamond, Oxfordshire, United Kingdom
I.R.R. Shinton
UMAN, Manchester, United Kingdom
E.J. Wallén
MAX-lab, Lund, Sweden
R. Weigel
Max-Planck Institute for Metal Research, Stuttgart, Germany

Superconductive insertion devices (IDs) have higher fields for a given gap and period length compared with the state-of-the-art technology of permanent magnet IDs. One of the still open issues for the development of superconductive insertion devices is the understanding of the heat intake from the electron beam. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the underlying mechanisms, a cold vacuum chamber for diagnostics was built. It is equipped with the following instrumentation: retarding field analyzers to measure the electron flux, temperature sensors to measure the beam heat load, pressure gauges, and mass spectrometers to measure the gas content. The flexibility of the engineering design will allow the installation of the cryostat in different synchrotron light sources. The installation in the storage ring of the Diamond Light Source is foreseen in November 2011. Here we report about the technical design of this device, the factory acceptance test and the planned measurements with electron beam.

MOPC013

Design, Fabrication and High Power RF Test of a C-band Accelerating Structure for Feasibility Study of the SPARC Photo-injector Energy Upgrade

89

D. Alesini, R. Boni, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo, F. Marcellini
INFN/LNF, Frascati (Roma), Italy
G. Campogiani, A. Mostacci, L. Palumbo, S. Persichelli, V. Spizzo
Rome University La Sapienza, Roma, Italy
T. Higo, K. Kakihara, S. Matsumoto
KEK, Ibaraki, Japan
S. Verdú-Andrés
TERA, Novara, Italy

The energy upgrade of the SPARC photo-injector from 170 to 250 MeV will be done by replacing a low gradient 3m S-Band structure with two 1.5m high gradient C-band structures. The structures are traveling wave, constant impedance sections, have symmetric waveguide input couplers and have been optimized to work with a SLED RF input pulse. A prototype with a reduced number of cells has been fabricated and tested at high power in KEK (Japan) giving very good performances in terms of breakdown rates at high accelerating gradient (>50 MV/m). The paper illustrates the design criteria of the structures, the fabrication procedure and the high power RF test results.

MOPS073

Impedance Calculation for Simple Models of Kickers in the Non-ultrarelativistic Regime

772

N. Biancacci, N. Mounet, E. Métral, B. Salvant, C. Zannini
CERN, Geneva, Switzerland
N. Biancacci, M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
Q. Qin, N. Wang
IHEP Beijing, Beijing, People's Republic of China

Kicker magnets are usually significant contributors to the beam coupling impedance of particle accelerators. An accurate understanding of their impedance is required in order to correctly assess the machine intensity limitations. The field matching method derived by H. Tsutsui for the longitudinal and transverse dipolar (driving) impedance of simple models of kickers in the ultrarelativistic regime was already extended to the non-ultrarelativistic case, and to the quadrupolar (detuning) impedance in the ultrarelativistic case. This contribution presents the extension to the quadrupolar impedance in the non-ultrarelativistic case, as well as benchmarks with other available methods to compute the impedance. In particular, all the components of the impedances are benchmarked with Tsutsui's model, i.e. in the ultrarelativistic limit, with the model for a flat chamber impedance recently computed by N. Mounet and E. Métral, in the case of finite relativistic gamma, and with CST Particle Studio simulations.

WEPC107

Development of a Steady State Simulation Code for Klystron Amplifiers

2265

C. Marrelli
CERN, Geneva, Switzerland
M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
B. Spataro
INFN/LNF, Frascati (Roma), Italy
S.G. Tantawi
SLAC, Menlo Park, California, USA

The design of klystrons is based on the intensive utilization of simulation codes, which can evaluate the complete beam-cavities interaction in the case of large signals. In the present work, we present the development of a 2-D steady state simulation code that can self-consistently evaluate the effects of the electromagnetic field on the particles and of the particles back on the field. The algorithm is based on the iterative solution of the power balance equation in the RF structures and allows determining the amplitude and phase of the electromagnetic field starting from the cavity modes. Some applications of the code to a single cavity and a two cavity klystron are presented and compared with the results obtained from other codes. The effect of the space charge forces in the klystron drift tubes is also evaluated.

TUPO008

Electron Linac Optimization for Driving Bright Gamma-ray Sources based on Compton Back-scattering

1461

L. Serafini, F. Broggi, C. De Martinis, D. Giove
Istituto Nazionale di Fisica Nucleare, Milano, Italy
D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, E. Chiadroni, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, P. Tomassini, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Maroli, V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy

We study the optimal lay-out and RF frequency for a room temperature GeV-class Electron Linac aiming at producing electron beams that enhance gamma-ray sources based on Compton back-scattering. These emerging novel sources, generating tunable, mono-chromatic, bright photon beams in the range of 5-20 MeV for nuclear physics as well as nuclear engineering, rely on both, high quality electron beams and J-class high repetition-rate synchronized laser systems in order to achieve the maximum spectral density of the gamma-ray beam (# photons/sec/eV). The best option among the conventionally used RF linac-bands (S, C, X) and possible hybrid schemes will be analyzed and discussed, focusing the study in terms of best performances for the gamma-ray source, its reliability and compactness. We show that the best possible candidates for a Gamma-ray driver are quite similar to those of FEL Linacs.

THPS101

Present and Perspectives of the Sparc THz Source

3669

E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
P. Calvani, S. Lupi, A. Nucara
Università di Roma I La Sapienza, Roma, Italy
L. Catani, B. Marchetti
INFN-Roma II, Roma, Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
O. Limaj
University of Rome La Sapienza, Rome, Italy
A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 10⁸ W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.

Paper	Title	Page
THYB01	Advanced Beam Manipulation Techniques at SPARC	2877
	A. Mostacci, D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, M. Castellano, E. Chiadroni, G. Di Pirro, A. Drago, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy B. Marchetti INFN-Roma II, Roma, Italy M. Migliorati University of Rome "La Sapienza", Rome, Italy L. Palumbo Rome University La Sapienza, Roma, Italy V. Petrillo, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	SPARC in Frascati is a high brightness photo-injector used to drive Free Electron Laser experiments and explore advanced beam manipulation techniques. The R&D effort made for the optimization of the beam parameters will be presented here, together with the major experimental results achieved. In particular, we will focus on the generation of sub-picosecond, high brightness electron bunch trains via velocity bunching technique (the so called comb beam). Such bunch trains can be used to drive tunable and narrow band THz sources, FELs and plasma wake field accelerators.
	Slides THYB01 [20.772 MB]

THPC100	Full Temporal Reconstruction using an Advanced Longitudinal Diagnostic at the SPARC FEL	3119
	G. Marcus, J.B. Rosenzweig UCLA, Los Angeles, California, USA M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, V. Surrenti ENEA C.R. Frascati, Frascati (Roma), Italy A. Bacci, M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci, A.R. Rossi INFN/LNF, Frascati (Roma), Italy A. Cianchi INFN-Roma II, Roma, Italy V. Petrillo Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy
	The Production of ultra-short (sub 100 fs) single-spike radiation possessing full longitudinal coherence from a free-electron laser (FEL) has been the subject of intense study. A Frequency-Resolved Optical Gating (FROG) diagnostic has been developed and tested at UCLA, which has the capability of providing a longitudinal reconstruction of these ultra-fast pulses. This paper reports the results of the application of the diagnostic at the SPARC FEL facility.

THPC159	Factory Acceptance Test of COLDDIAG: A Cold Vacuum Chamber for Diagnostics	3263
	S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany V. Baglin CERN, Geneva, Switzerland C. Boffo, G. Sikler BNG, Würzburg, Germany T.W. Bradshaw STFC/RAL, Chilton, Didcot, Oxon, United Kingdom R. Cimino, M. Commisso, A. Mostacci, B. Spataro INFN/LNF, Frascati (Roma), Italy J.A. Clarke, R.M. Jones, D.J. Scott Cockcroft Institute, Warrington, Cheshire, United Kingdom M.P. Cox, J.C. Schouten Diamond, Oxfordshire, United Kingdom I.R.R. Shinton UMAN, Manchester, United Kingdom E.J. Wallén MAX-lab, Lund, Sweden R. Weigel Max-Planck Institute for Metal Research, Stuttgart, Germany
	Superconductive insertion devices (IDs) have higher fields for a given gap and period length compared with the state-of-the-art technology of permanent magnet IDs. One of the still open issues for the development of superconductive insertion devices is the understanding of the heat intake from the electron beam. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the underlying mechanisms, a cold vacuum chamber for diagnostics was built. It is equipped with the following instrumentation: retarding field analyzers to measure the electron flux, temperature sensors to measure the beam heat load, pressure gauges, and mass spectrometers to measure the gas content. The flexibility of the engineering design will allow the installation of the cryostat in different synchrotron light sources. The installation in the storage ring of the Diamond Light Source is foreseen in November 2011. Here we report about the technical design of this device, the factory acceptance test and the planned measurements with electron beam.

MOPC013	Design, Fabrication and High Power RF Test of a C-band Accelerating Structure for Feasibility Study of the SPARC Photo-injector Energy Upgrade	89
	D. Alesini, R. Boni, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo, F. Marcellini INFN/LNF, Frascati (Roma), Italy G. Campogiani, A. Mostacci, L. Palumbo, S. Persichelli, V. Spizzo Rome University La Sapienza, Roma, Italy T. Higo, K. Kakihara, S. Matsumoto KEK, Ibaraki, Japan S. Verdú-Andrés TERA, Novara, Italy
	The energy upgrade of the SPARC photo-injector from 170 to 250 MeV will be done by replacing a low gradient 3m S-Band structure with two 1.5m high gradient C-band structures. The structures are traveling wave, constant impedance sections, have symmetric waveguide input couplers and have been optimized to work with a SLED RF input pulse. A prototype with a reduced number of cells has been fabricated and tested at high power in KEK (Japan) giving very good performances in terms of breakdown rates at high accelerating gradient (>50 MV/m). The paper illustrates the design criteria of the structures, the fabrication procedure and the high power RF test results.

MOPS073	Impedance Calculation for Simple Models of Kickers in the Non-ultrarelativistic Regime	772
	N. Biancacci, N. Mounet, E. Métral, B. Salvant, C. Zannini CERN, Geneva, Switzerland N. Biancacci, M. Migliorati, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy Q. Qin, N. Wang IHEP Beijing, Beijing, People's Republic of China
	Kicker magnets are usually significant contributors to the beam coupling impedance of particle accelerators. An accurate understanding of their impedance is required in order to correctly assess the machine intensity limitations. The field matching method derived by H. Tsutsui for the longitudinal and transverse dipolar (driving) impedance of simple models of kickers in the ultrarelativistic regime was already extended to the non-ultrarelativistic case, and to the quadrupolar (detuning) impedance in the ultrarelativistic case. This contribution presents the extension to the quadrupolar impedance in the non-ultrarelativistic case, as well as benchmarks with other available methods to compute the impedance. In particular, all the components of the impedances are benchmarked with Tsutsui's model, i.e. in the ultrarelativistic limit, with the model for a flat chamber impedance recently computed by N. Mounet and E. Métral, in the case of finite relativistic gamma, and with CST Particle Studio simulations.

WEPC107	Development of a Steady State Simulation Code for Klystron Amplifiers	2265
	C. Marrelli CERN, Geneva, Switzerland M. Migliorati, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy B. Spataro INFN/LNF, Frascati (Roma), Italy S.G. Tantawi SLAC, Menlo Park, California, USA
	The design of klystrons is based on the intensive utilization of simulation codes, which can evaluate the complete beam-cavities interaction in the case of large signals. In the present work, we present the development of a 2-D steady state simulation code that can self-consistently evaluate the effects of the electromagnetic field on the particles and of the particles back on the field. The algorithm is based on the iterative solution of the power balance equation in the RF structures and allows determining the amplitude and phase of the electromagnetic field starting from the cavity modes. Some applications of the code to a single cavity and a two cavity klystron are presented and compared with the results obtained from other codes. The effect of the space charge forces in the klystron drift tubes is also evaluated.

TUPO008	Electron Linac Optimization for Driving Bright Gamma-ray Sources based on Compton Back-scattering	1461
	L. Serafini, F. Broggi, C. De Martinis, D. Giove Istituto Nazionale di Fisica Nucleare, Milano, Italy D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, E. Chiadroni, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, P. Tomassini, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy C. Maroli, V. Petrillo Universita' degli Studi di Milano, Milano, Italy M. Migliorati, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy
	We study the optimal lay-out and RF frequency for a room temperature GeV-class Electron Linac aiming at producing electron beams that enhance gamma-ray sources based on Compton back-scattering. These emerging novel sources, generating tunable, mono-chromatic, bright photon beams in the range of 5-20 MeV for nuclear physics as well as nuclear engineering, rely on both, high quality electron beams and J-class high repetition-rate synchronized laser systems in order to achieve the maximum spectral density of the gamma-ray beam (# photons/sec/eV). The best option among the conventionally used RF linac-bands (S, C, X) and possible hybrid schemes will be analyzed and discussed, focusing the study in terms of best performances for the gamma-ray source, its reliability and compactness. We show that the best possible candidates for a Gamma-ray driver are quite similar to those of FEL Linacs.

THPS101	Present and Perspectives of the Sparc THz Source	3669
	E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy P. Calvani, S. Lupi, A. Nucara Università di Roma I La Sapienza, Roma, Italy L. Catani, B. Marchetti INFN-Roma II, Roma, Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy O. Limaj University of Rome La Sapienza, Rome, Italy A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 10⁸ W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.