FEL2012 - List of Authors (Chiadroni, E.)

Paper

Title

Page

Optical Diffraction Radiation Interference as a Non-intercepting Emittance Measurement for High Brightness and High Repetition Rate Electron Beam

353

A. Cianchi, L. Catani, E. Chiadroni
INFN-Roma II, Roma, Italy
V. Balandin, N. Golubeva, K. Honkavaara, G. Kube
DESY, Hamburg, Germany
M. Castellano
INFN/LNF, Frascati (Roma), Italy
M. Migliorati
URLS, Rome, Italy

Conventional intercepting transverse electron beam diagnostics, as the one based on Optical Transition Radiation (OTR), cannot tolerate high power beams without significant mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR), instead, is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitation of this method is the low signal to noise ratio, mainly due to the synchrotron radiation background. This problem can be overcome by using ODRI (ODR Interference). In this case the beam goes through slits opened in two metallic foils placed at a distance shorter than the radiation formation zone. Due to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. We report here the result of the first measurements of the beam emittance using ODRI carried out at FLASH (DESY). Our result demonstrate the unique potential of this technique suitable to be used as not intercepting diagnostic in every machine with high brightness and high repetition rate electron beam.

Slides WEOB02 [1.928 MB]

THOC03

Measurement of the Transverse Coherence of the Sase FEL Radiation in The Optical Range Using an Heterodyne Speckle Method

551

M.D. Alaimo, M. Manfredda, M.A.C. Potenza, D. Redoglio
Universita' degli Studi di Milano & INFN, Milano, Italy
M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, C. Ronsivalle, V. Surrenti, A. Torre
ENEA C.R. Frascati, Frascati (Roma), Italy
M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
J.V. Rau
ISM-CNR, Rome, Italy

An heterodyne speckle approach has been applied for measuring the transverse coherence of FEL radiation in SASE regime in the optical region (400nm) at SPARC (LNF, Frascati - Italy). It turned out that the coherence length is comparable with the beam size and only slight variations of the coherence properties have been observed after the 5th undulator section. The technique needs a very essential setup composed only by a water suspension of commercial colloidal particles and a CCD camera. The Complex Coherence Factor is retrieved from the Fourier analysis of the interference pattern generated by the stochastic superposition of the almost spherical waves scattered by the particles and the unperturbed transmitted beam (heterodyne speckles). This approach does not require the engineering of ad-hoc devices and provides a two-dimensional map of the transverse coherence without any a-priori assumption about its functional form. The method is suitable for one-shot characterization and it works in the X-ray wavelength as well. It has been previously developed and tested to be effective with synchrotron radiation [*,**] (ID02 and ID06 at ESRF, Grenoble).
* M.D. Alaimo, M.A.C. Potenza, M. Manfredda, G. Geloni, M. Sztucki, T. Narayanan & M. Giglio, Phys. Rev. Lett. 10³ (2009).
** M. Manfredda et al., in preparation

Slides THOC03 [8.489 MB]

Paper	Title	Page
WEOB02	Optical Diffraction Radiation Interference as a Non-intercepting Emittance Measurement for High Brightness and High Repetition Rate Electron Beam	353
	A. Cianchi, L. Catani, E. Chiadroni INFN-Roma II, Roma, Italy V. Balandin, N. Golubeva, K. Honkavaara, G. Kube DESY, Hamburg, Germany M. Castellano INFN/LNF, Frascati (Roma), Italy M. Migliorati URLS, Rome, Italy
	Conventional intercepting transverse electron beam diagnostics, as the one based on Optical Transition Radiation (OTR), cannot tolerate high power beams without significant mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR), instead, is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitation of this method is the low signal to noise ratio, mainly due to the synchrotron radiation background. This problem can be overcome by using ODRI (ODR Interference). In this case the beam goes through slits opened in two metallic foils placed at a distance shorter than the radiation formation zone. Due to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. We report here the result of the first measurements of the beam emittance using ODRI carried out at FLASH (DESY). Our result demonstrate the unique potential of this technique suitable to be used as not intercepting diagnostic in every machine with high brightness and high repetition rate electron beam.
	Slides WEOB02 [1.928 MB]

THOC03	Measurement of the Transverse Coherence of the Sase FEL Radiation in The Optical Range Using an Heterodyne Speckle Method	551
	M.D. Alaimo, M. Manfredda, M.A.C. Potenza, D. Redoglio Universita' degli Studi di Milano & INFN, Milano, Italy M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, C. Ronsivalle, V. Surrenti, A. Torre ENEA C.R. Frascati, Frascati (Roma), Italy M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Petrillo, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy
	An heterodyne speckle approach has been applied for measuring the transverse coherence of FEL radiation in SASE regime in the optical region (400nm) at SPARC (LNF, Frascati - Italy). It turned out that the coherence length is comparable with the beam size and only slight variations of the coherence properties have been observed after the 5th undulator section. The technique needs a very essential setup composed only by a water suspension of commercial colloidal particles and a CCD camera. The Complex Coherence Factor is retrieved from the Fourier analysis of the interference pattern generated by the stochastic superposition of the almost spherical waves scattered by the particles and the unperturbed transmitted beam (heterodyne speckles). This approach does not require the engineering of ad-hoc devices and provides a two-dimensional map of the transverse coherence without any a-priori assumption about its functional form. The method is suitable for one-shot characterization and it works in the X-ray wavelength as well. It has been previously developed and tested to be effective with synchrotron radiation [,] (ID02 and ID06 at ESRF, Grenoble). M.D. Alaimo, M.A.C. Potenza, M. Manfredda, G. Geloni, M. Sztucki, T. Narayanan & M. Giglio, Phys. Rev. Lett. 10³ (2009). ** M. Manfredda et al., in preparation
	Slides THOC03 [8.489 MB]