IPAC2017 - List of Authors (Carli, C.)

Paper	Title	Page
MOPAB112	Schottky Based Intensity Measurements and Errors Due to Statistical Fluctuations	385
	C. Carli, M.E. Angoletta, F. Caspers, O.R. Jones, F. Pedersen, J. Sanchez-Quesada, L. Søby CERN, Geneva, Switzerland
	The beam intensities at the Extra Low ENergy Antiproton ring ELENA are too low for standard beam current transformers and, thus, are measured with longitudinal Schottky diagnostics. This method is already successfully used at the Antiproton Decelerator since the commissioning of this machine. The fact that Schottky noise is a statistical phenomenon implies statistical errors of these measurements. Simple analytical formulas describing the statistical error to be expected as a function of the frequency spread of the band considered, the time resolution chosen and the background noise have been derived. On the one hand, low revolution harmonics and, in turn, frequency spread of the band analysed lead to large measurement errors as this situation corresponds to low momentum resolution of the resulting distribution describing the beam. At very large revolution harmonics and, thus, frequency spreads of the band analysed, the measurement error increases again due to additional contributions from the background noise.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB112
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MOPAB127	A New Method for Emittance Reconstruction Using a Scraper in a Dispersive Region of a Low Energy Storage Ring	429
SUSPSIK081	use link to see paper's listing under its alternate paper code
	J.R. Hunt, J. Resta-López, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom C. Carli CERN, Geneva, Switzerland J.R. Hunt, J. Resta-López, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Funding Council, UK CERN Beam scraping is a standard method for beam emittance measurements at low energies and will be applied at the Extra Low ENergy Antimatter (ELENA) ring. However, in ELENA, as in many other low energy storage rings, the scraper is located in a position of finite dispersion which poses a unique challenge when reconstructing the emittance from beam intensity data. A new algorithm for ELENA and other machines that use a scraper in a dispersive region has been developed. It combines data obtained by scraping the beam from opposite sides with information on the storage ring lattice. In this contribution, the new algorithm is presented, tested using simulations and compared with alternate methods for emittance reconstruction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB127
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WEPVA034	ELENA - From Installation to Commissioning	3327
	T. Eriksson, W. Bartmann, P. Belochitskii, L. Bojtár, H. Breuker, F. Butin, C. Carli, B. Dupuy, P. Freyermuth, L.V. Jørgensen, B. Lefort, J. Mertens, R. Ostojić, S. Pasinelli, G. Tranquille CERN, Geneva, Switzerland W. Oelert Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany
	ELENA (Extra Low ENergy Antiproton ring) is an upgrade project at the CERN AD (Antiproton Decelerator). The smaller ELENA ring will further decelerate 5.3 MeV antiprotons from the AD ring down to 100 keV using electron cooling to obtain good deceleration efficiency and dense beams. An increase of up to two orders of magnitude in trapping efficiency is expected at the AD experiments. This paper will report on the current status of ELENA where beam commissioning of the ring is now taking place. Phase one of the project installation has been completed with ring and injection lines in place, while phase two will finalize the project with installation of 100 keV transfer lines connecting the experiments to ELENA and is planned to take place in 2019/2020.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA034
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WEPVA035	The PSB Operational Scenario with Longitudinal Painting Injection in the Post-LIU Era	3331
	V. Forte, S.C.P. Albright, M.E. Angoletta, P. Baudrenghien, E. Benedetto, A. Blas, C. Bracco, C. Carli, A. Findlay, R. Garoby, G. Hagmann, A.M. Lombardi, B. Mikulec, M.M. Paoluzzi, J.L. Sanchez Alvarez, R. Wegner CERN, Geneva, Switzerland
	Longitudinal painting has been presented as an elegant technique to fill the longitudinal phase space at injection to the CERN PSB once it is connected with the new Linac4. Painting brings several advantages related to a more controlled longitudinal filamentation, lower peak line density and beating reduction, resulting in a smaller space-charge tune spread. This could be an advantage especially for high intensity beams (> 6·10¹² protons per bunch) to limit losses on the transverse acceptance of the machine. This paper presents an overview on the possible advantages of the technique for operational and test beams, taking care of the hardware limitations and possible failure scenarios.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA035
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THPIK092	Considerations on the Effect of Magnet Yoke Dilution on Remanent Field at ELENA	4299
	C. Carli, L. Fiscarelli, D. Schoerling CERN, Geneva, Switzerland
	The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron constructed at CERN to decelerate antiprotons down to 100 keV and, thus, operated at very low magnetic fields. The CERN magnet group has carried out extensive investigations on accelerator magnets for very low fields, comprising theoretical studies and the construction of several prototype magnets, to ensure that the required field quality can be reached at these very low fields. In the course of this work, experimental investigations [1] led to the initially unexpected observation that dilution of the yoke, i.e. alternating laminations made of electric steel with thicker non-magnetic stainless steel laminations, increases the remnant field. An explanation for this behaviour has already been anticipated in a previous paper [2]. Here, we treat this specific topic in analytical detail. We come to the conclusion that magnet yoke thinning in most practical situations does not improve the field quality at very low field levels, but rather enhances the impact from hysteresis and remanence effects. [1] L.Fiscarelli, Magnetic measurements on the quadrupoles prototypes for ELENA (PXMQNLGNAP), CERN internal report. [2] D. Schoerling, Case Study of a Magnetic System for low-Energy Machines, PRAB 19, 082401 (2016).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK092
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THPIK093	Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA	4303
	C. Carli, M. Martini CERN, Geneva, Switzerland
	Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK093
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Paper

Title

Page

Schottky Based Intensity Measurements and Errors Due to Statistical Fluctuations

385

C. Carli, M.E. Angoletta, F. Caspers, O.R. Jones, F. Pedersen, J. Sanchez-Quesada, L. Søby
CERN, Geneva, Switzerland

The beam intensities at the Extra Low ENergy Antiproton ring ELENA are too low for standard beam current transformers and, thus, are measured with longitudinal Schottky diagnostics. This method is already successfully used at the Antiproton Decelerator since the commissioning of this machine. The fact that Schottky noise is a statistical phenomenon implies statistical errors of these measurements. Simple analytical formulas describing the statistical error to be expected as a function of the frequency spread of the band considered, the time resolution chosen and the background noise have been derived. On the one hand, low revolution harmonics and, in turn, frequency spread of the band analysed lead to large measurement errors as this situation corresponds to low momentum resolution of the resulting distribution describing the beam. At very large revolution harmonics and, thus, frequency spreads of the band analysed, the measurement error increases again due to additional contributions from the background noise.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB112

Export •

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

MOPAB127

A New Method for Emittance Reconstruction Using a Scraper in a Dispersive Region of a Low Energy Storage Ring

429

SUSPSIK081

use link to see paper's listing under its alternate paper code

J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
C. Carli
CERN, Geneva, Switzerland
J.R. Hunt, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Funding Council, UK CERN
Beam scraping is a standard method for beam emittance measurements at low energies and will be applied at the Extra Low ENergy Antimatter (ELENA) ring. However, in ELENA, as in many other low energy storage rings, the scraper is located in a position of finite dispersion which poses a unique challenge when reconstructing the emittance from beam intensity data. A new algorithm for ELENA and other machines that use a scraper in a dispersive region has been developed. It combines data obtained by scraping the beam from opposite sides with information on the storage ring lattice. In this contribution, the new algorithm is presented, tested using simulations and compared with alternate methods for emittance reconstruction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB127

Export •

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

WEPVA034

ELENA - From Installation to Commissioning

3327

T. Eriksson, W. Bartmann, P. Belochitskii, L. Bojtár, H. Breuker, F. Butin, C. Carli, B. Dupuy, P. Freyermuth, L.V. Jørgensen, B. Lefort, J. Mertens, R. Ostojić, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany

ELENA (Extra Low ENergy Antiproton ring) is an upgrade project at the CERN AD (Antiproton Decelerator). The smaller ELENA ring will further decelerate 5.3 MeV antiprotons from the AD ring down to 100 keV using electron cooling to obtain good deceleration efficiency and dense beams. An increase of up to two orders of magnitude in trapping efficiency is expected at the AD experiments. This paper will report on the current status of ELENA where beam commissioning of the ring is now taking place. Phase one of the project installation has been completed with ring and injection lines in place, while phase two will finalize the project with installation of 100 keV transfer lines connecting the experiments to ELENA and is planned to take place in 2019/2020.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA034

Export •

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

WEPVA035

The PSB Operational Scenario with Longitudinal Painting Injection in the Post-LIU Era

3331

V. Forte, S.C.P. Albright, M.E. Angoletta, P. Baudrenghien, E. Benedetto, A. Blas, C. Bracco, C. Carli, A. Findlay, R. Garoby, G. Hagmann, A.M. Lombardi, B. Mikulec, M.M. Paoluzzi, J.L. Sanchez Alvarez, R. Wegner
CERN, Geneva, Switzerland

Longitudinal painting has been presented as an elegant technique to fill the longitudinal phase space at injection to the CERN PSB once it is connected with the new Linac4. Painting brings several advantages related to a more controlled longitudinal filamentation, lower peak line density and beating reduction, resulting in a smaller space-charge tune spread. This could be an advantage especially for high intensity beams (> 6·10¹² protons per bunch) to limit losses on the transverse acceptance of the machine. This paper presents an overview on the possible advantages of the technique for operational and test beams, taking care of the hardware limitations and possible failure scenarios.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA035

Export •

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

THPIK092

Considerations on the Effect of Magnet Yoke Dilution on Remanent Field at ELENA

4299

C. Carli, L. Fiscarelli, D. Schoerling
CERN, Geneva, Switzerland

The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron constructed at CERN to decelerate antiprotons down to 100 keV and, thus, operated at very low magnetic fields. The CERN magnet group has carried out extensive investigations on accelerator magnets for very low fields, comprising theoretical studies and the construction of several prototype magnets, to ensure that the required field quality can be reached at these very low fields. In the course of this work, experimental investigations [1] led to the initially unexpected observation that dilution of the yoke, i.e. alternating laminations made of electric steel with thicker non-magnetic stainless steel laminations, increases the remnant field. An explanation for this behaviour has already been anticipated in a previous paper [2]. Here, we treat this specific topic in analytical detail. We come to the conclusion that magnet yoke thinning in most practical situations does not improve the field quality at very low field levels, but rather enhances the impact from hysteresis and remanence effects.
[1] L.Fiscarelli, Magnetic measurements on the quadrupoles prototypes for ELENA (PXMQNLGNAP), CERN internal report.
[2] D. Schoerling, Case Study of a Magnetic System for low-Energy Machines, PRAB 19, 082401 (2016).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK092

Export •

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

THPIK093

Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA

4303

C. Carli, M. Martini
CERN, Geneva, Switzerland

Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK093

Export •

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