IBIC2016 - List of Authors (Roncarolo, F.)

Paper	Title	Page
MOPG74	Design and Performance of Coronagraph for Beam Halo Measurements in the LHC	253
	A. Goldblatt, E. Bravin, F. Roncarolo, G. Trad CERN, Geneva, Switzerland T.M. Mitsuhashi KEK, Ibaraki, Japan
	The CERN Large Hadron Collider is equipped with two Beam Synchrotron Radiation (BSR) systems, one per beam, used to monitor the transverse distribution of the beam, its longitudinal distribution and the abort gap population. During the 2015-2016 winter shut-down period, one of the two BSR systems was equipped with a prototype beam halo monitor, based on the coronagraph technique, classically used in astrophysics telescopes to measure the sun corona. The system design, as well as its optics, was inherited from the coronagraph used in the KEK Photon Factory with some modifications made in order to satisfy the LHC BSR source constraints. This project is in the framework of the HL-LHC project, for which there is the requirement to monitor the beam halo at the level of 10^-6 of the core intensity. This first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10-3 to 10-4 range. After discussing the design of the LHC coronagraph and its technical implementation, this contribution presents the result of the first tests with beam and the planned system upgrades for 2017.
	Poster MOPG74 [1.671 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG74
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TUPG77	Experimental Results of a Compact Laserwire System for Non-Invasive H⁻ Beam Profile Measurements at CERN's Linac4	544
	S.M. Gibson, G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom T. Hofmann, U. Raich, F. Roncarolo CERN, Geneva, Switzerland
	Funding: Support from UK STFC, grant ST/N001753/1. A non-invasive laserwire system is being developed for quasi-continuous monitoring of the transverse profile and emittance of the final 160 MeV beam at CERN's LINAC4. As part of these developments, a compact laser-based profile monitor was recently tested during LINAC4 commissioning at beam energies of 50 MeV, 80 MeV and 10⁷ MeV. A laser with a tunable pulse width (1-300 ns) and ~200 W peak power in a surface hutch delivers light via a 75 m LMA transport fibre to the accelerator. Automated scanning optics deliver a free space <150 micron width laserwire to the interaction chamber, where a transverse slice of the hydrogen ion beam is neutralised via photo-detachment. The liberated electrons are deflected by a low field dipole and captured by a sCVD diamond detector, that can be scanned in synchronisation with the laserwire position. The laserwire profile of the LINAC4 beam has been measured at all commissioning energies and is found in very good agreement with interpolated profiles from conventional SEM-grid and wire scanner measurements, positioned up and downstream of the laserwire setup. Improvements based on these prototype tests for the design of the final system are presented.
	Poster TUPG77 [3.695 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG77
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WEBL02	Beam Size Measurements Using Interferometry at LHC	583
	G. Trad, E. Bravin, A. Goldblatt, S. Mazzoni, F. Roncarolo CERN, Geneva, Switzerland T.M. Mitsuhashi KEK, Ibaraki, Japan
	During the long LHC shutdown 2013-2014, both the LHC and its injector chain underwent significant upgrades. The most important changes concerned increasing the maximum LHC beam energy from 4TeV to 6.5TeV and reducing the transverse emittance of the beam from the LHC injectors. These upgrades pose challenges to the measurement of the transverse beam size via Synchrotron Radiation (SR) imaging, as the radiation parameters approach the diffraction limit. Optical SR interferometry, widely used in synchrotron light facilities, was considered as an alternative method to measure the 150 'm rms beam size at top energy as it allows measurements below the diffraction limit. A system based on this technique was therefore implemented in the LHC, for the first time on a proton machine. This paper describes the design of the LHC interferometer and its two SR sources (a superconducting undulator at low energy and a bending dipole at high energy), along with the expected performance in terms of beam size measurement as compared to the imaging system. The world's first proton beam interferogram measured at the LHC will be shown and plans to make this an operational monitor will be presented.
	Slides WEBL02 [42.662 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEBL02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Design and Performance of Coronagraph for Beam Halo Measurements in the LHC

253

A. Goldblatt, E. Bravin, F. Roncarolo, G. Trad
CERN, Geneva, Switzerland
T.M. Mitsuhashi
KEK, Ibaraki, Japan

The CERN Large Hadron Collider is equipped with two Beam Synchrotron Radiation (BSR) systems, one per beam, used to monitor the transverse distribution of the beam, its longitudinal distribution and the abort gap population. During the 2015-2016 winter shut-down period, one of the two BSR systems was equipped with a prototype beam halo monitor, based on the coronagraph technique, classically used in astrophysics telescopes to measure the sun corona. The system design, as well as its optics, was inherited from the coronagraph used in the KEK Photon Factory with some modifications made in order to satisfy the LHC BSR source constraints. This project is in the framework of the HL-LHC project, for which there is the requirement to monitor the beam halo at the level of 10^-6 of the core intensity. This first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10-3 to 10-4 range. After discussing the design of the LHC coronagraph and its technical implementation, this contribution presents the result of the first tests with beam and the planned system upgrades for 2017.

Poster MOPG74 [1.671 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG74

Export •

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

TUPG77

Experimental Results of a Compact Laserwire System for Non-Invasive H⁻ Beam Profile Measurements at CERN's Linac4

544

S.M. Gibson, G.E. Boorman, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
T. Hofmann, U. Raich, F. Roncarolo
CERN, Geneva, Switzerland

Funding: Support from UK STFC, grant ST/N001753/1.
A non-invasive laserwire system is being developed for quasi-continuous monitoring of the transverse profile and emittance of the final 160 MeV beam at CERN's LINAC4. As part of these developments, a compact laser-based profile monitor was recently tested during LINAC4 commissioning at beam energies of 50 MeV, 80 MeV and 10⁷ MeV. A laser with a tunable pulse width (1-300 ns) and ~200 W peak power in a surface hutch delivers light via a 75 m LMA transport fibre to the accelerator. Automated scanning optics deliver a free space <150 micron width laserwire to the interaction chamber, where a transverse slice of the hydrogen ion beam is neutralised via photo-detachment. The liberated electrons are deflected by a low field dipole and captured by a sCVD diamond detector, that can be scanned in synchronisation with the laserwire position. The laserwire profile of the LINAC4 beam has been measured at all commissioning energies and is found in very good agreement with interpolated profiles from conventional SEM-grid and wire scanner measurements, positioned up and downstream of the laserwire setup. Improvements based on these prototype tests for the design of the final system are presented.

Poster TUPG77 [3.695 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG77

Export •

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

WEBL02

Beam Size Measurements Using Interferometry at LHC

583

G. Trad, E. Bravin, A. Goldblatt, S. Mazzoni, F. Roncarolo
CERN, Geneva, Switzerland
T.M. Mitsuhashi
KEK, Ibaraki, Japan

During the long LHC shutdown 2013-2014, both the LHC and its injector chain underwent significant upgrades. The most important changes concerned increasing the maximum LHC beam energy from 4TeV to 6.5TeV and reducing the transverse emittance of the beam from the LHC injectors. These upgrades pose challenges to the measurement of the transverse beam size via Synchrotron Radiation (SR) imaging, as the radiation parameters approach the diffraction limit. Optical SR interferometry, widely used in synchrotron light facilities, was considered as an alternative method to measure the 150 'm rms beam size at top energy as it allows measurements below the diffraction limit. A system based on this technique was therefore implemented in the LHC, for the first time on a proton machine. This paper describes the design of the LHC interferometer and its two SR sources (a superconducting undulator at low energy and a bending dipole at high energy), along with the expected performance in terms of beam size measurement as compared to the imaging system. The world's first proton beam interferogram measured at the LHC will be shown and plans to make this an operational monitor will be presented.

Slides WEBL02 [42.662 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEBL02

Export •

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