IBIC2023 - List of Authors (Lannoy, C.)

Paper	Title	Page
WEP034	Effect of Longitudinal Beam-Coupling Impedance on the Schottky Spectrum of Bunched Beams	428
	C. Lannoy, D. Alves, K. Łasocha, N. Mounet CERN, Meyrin, Switzerland C. Lannoy, T. Pieloni EPFL, Lausanne, Switzerland
	Schottky spectra can be strongly affected by collective effects, in particular those arising from beam-coupling impedance when a large number of bunch charges are involved. In such conditions, the direct interpretation of the measured spectra becomes difficult, which prevents the extraction of beam and machine parameters in the same way as is usually done for lower bunch charges. Since no theory is yet directly applicable to predict the impact of impedance on such spectra, we use here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky spectrum for various machine and beam conditions, such as the ones found at the Large Hadron Collider. A simple longitudinal resonator-like impedance model is introduced in the simulations and its effect studied in different configurations, allowing preliminary interpretations of the impact of longitudinal impedance on Schottky spectra.
	Poster WEP034 [1.237 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WEP034
About •	Received ※ 05 September 2023 — Revised ※ 10 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 22 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP035	Statistical Properties of Schottky Spectra	433
	C. Lannoy, D. Alves, K. Łasocha, N. Mounet CERN, Meyrin, Switzerland C. Lannoy, T. Pieloni EPFL, Lausanne, Switzerland
	Schottky signals are used for non-invasive beam diagnostics as they contain information on various beam and machine parameters. The instantaneous Schottky signal is, however, only a single realisation of a random process, implicitly depending on the discrete distribution of synchrotron and betatron amplitudes and phases among the particles. To estimate the expected value of the Schottky power spectrum, and reveal the inner structure of the Bessel satellites described by the theory, the averaging of instantaneous Schottky spectra is required. This study describes this procedure quantitatively by analysing the statistical properties of the Schottky signals, including the expected value and variance of Schottky power spectra. Furthermore, we investigate how these quantities evolve with the number of particles in the bunch, the observed harmonic of the revolution frequency, the distribution of synchrotron oscillation amplitudes, and the bunch profile. The theoretical findings are compared against macro-particle simulations as well as Monte Carlo computations.
	Poster WEP035 [3.908 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WEP035
About •	Received ※ 05 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 29 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Effect of Longitudinal Beam-Coupling Impedance on the Schottky Spectrum of Bunched Beams

428

C. Lannoy, D. Alves, K. Łasocha, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland

Schottky spectra can be strongly affected by collective effects, in particular those arising from beam-coupling impedance when a large number of bunch charges are involved. In such conditions, the direct interpretation of the measured spectra becomes difficult, which prevents the extraction of beam and machine parameters in the same way as is usually done for lower bunch charges. Since no theory is yet directly applicable to predict the impact of impedance on such spectra, we use here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky spectrum for various machine and beam conditions, such as the ones found at the Large Hadron Collider. A simple longitudinal resonator-like impedance model is introduced in the simulations and its effect studied in different configurations, allowing preliminary interpretations of the impact of longitudinal impedance on Schottky spectra.

Poster WEP034 [1.237 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WEP034

About •

Received ※ 05 September 2023 — Revised ※ 10 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 22 September 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP035

Statistical Properties of Schottky Spectra

433

C. Lannoy, D. Alves, K. Łasocha, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland

Schottky signals are used for non-invasive beam diagnostics as they contain information on various beam and machine parameters. The instantaneous Schottky signal is, however, only a single realisation of a random process, implicitly depending on the discrete distribution of synchrotron and betatron amplitudes and phases among the particles. To estimate the expected value of the Schottky power spectrum, and reveal the inner structure of the Bessel satellites described by the theory, the averaging of instantaneous Schottky spectra is required. This study describes this procedure quantitatively by analysing the statistical properties of the Schottky signals, including the expected value and variance of Schottky power spectra. Furthermore, we investigate how these quantities evolve with the number of particles in the bunch, the observed harmonic of the revolution frequency, the distribution of synchrotron oscillation amplitudes, and the bunch profile. The theoretical findings are compared against macro-particle simulations as well as Monte Carlo computations.

Poster WEP035 [3.908 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WEP035

About •

Received ※ 05 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 29 September 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)