eeFACT2016 - List of Keywords (polarization)

Paper	Title	Other Keywords	Page
MOT4H6	Simulations of Polarization Levels and Spin Tune Biases in High Energy Leptons Storage Rings	ion, quadrupole, wiggler, alignment	43
	E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance LLC. Under DE-AC02-07CH11359 with the U.S. DOE Simulations of polarization levels and spin tune biases in high energy leptons storage rings The use of resonant depolarization has been suggested for precise beam energy measurements in the 100 km long Future Circular Collider e⁺e⁻. The principle behind resonant depolarization is that a vertically polarized beam excited through an oscillating horizontal magnetic field gets depolarized when the excitation frequency is in a given relationship with the beam energy. In this paper the possibility of self-polarized leptons at 45 and 80 GeV is investigated. Preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified ring are presented. Even in presence of errors a level of polarization useful for energy calibration seems not out of reach. However it is crucial to demonstrate that a energy measurement precision better than 100 KeV can be actually obtained. The last ring layout with 1 mm vertical beta at the IPs has been also considered. The large vertical beta in the IR quadrupoles makes the closed orbit very sensitive to their vertical misalignment and the orbit correction procedure challenging.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-MOT4H6
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOT4H7	Ideas for Siberian Snakes and Spin Rotators in Very High Energy e⁺e⁻ Rings	ion, solenoid, dipole, synchrotron	47
	S.R. Mane Convergent Computing, Shoreham, New York, USA
	The high value of the radiated power in synchrotron radiation in very high energy e⁺e⁻ storage rings presents unique challenges for the design of Siberian Snakes and spin rotators in such machines. This paper presents some ideas which may lead to a feasible design of such devices. The idea is to employ solenoids interleaved with the arc dipoles, to yield a set of noncommuting spin rotations, which can rotate an initially vertical spin to any desired direction. The solenoids should be (approximately) optically transparent, and can be 'spin matched' to the ring using known procedures. Preliminary numerical studies indicate the design may be feasible.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-MOT4H7
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WET1H4	Measurement of Beam Polarization and Beam Energy in One Device	ion, electron, photon, laser	168
	N.Yu. Muchnoi BINP SB RAS, Novosibirsk, Russia
	Funding: Russian Science Foundation N 14-50-00080 Electron beam interaction with the monochromatic laser radiation produces scattered photons and electrons due to the Compton effect. Both types of scattered particles carry the information about the polarisation (if any) and the energy of initial electrons in the beam. This report is focused on the properties of the scattered electrons. After a bending magnet these electrons leave the beam and their X-Y space distribution is supposed to be measured by the 2D pixel detector. We show that if the electron beam vertical emittance is sufficiently small, the shape of this distribution is an ellipse. Measurement of the length of the X-axis of this ellipse allow to calibrate accurately the bending field integral seen by the beam. The distribution of the electrons within the ellipse depends on the initial beam polarisation, allowing to measure its degree and direction. So we propose a universal Compton polarimeter with a unique feature of precise calibration of the LEP-style beam energy spectrometer. The approach is thought to be useful for the future high-energy e⁺/e⁻ colliders, while the feasibility tests need to be performed on existing accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-WET1H4
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THS2H3	Summary of Beam Instrumentation and Beam Diagnostics Session	ion, instrumentation, electron, feedback	220
	H. Fukuma KEK, Ibaraki, Japan
	This report is a summary of the beam instrumentation and beam diagnostics session of the eeFACT2016 workshop.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-THS2H3
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOT4H6

Simulations of Polarization Levels and Spin Tune Biases in High Energy Leptons Storage Rings

ion, quadrupole, wiggler, alignment

43

E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance LLC. Under DE-AC02-07CH11359 with the U.S. DOE
Simulations of polarization levels and spin tune biases in high energy leptons storage rings The use of resonant depolarization has been suggested for precise beam energy measurements in the 100 km long Future Circular Collider e⁺e⁻. The principle behind resonant depolarization is that a vertically polarized beam excited through an oscillating horizontal magnetic field gets depolarized when the excitation frequency is in a given relationship with the beam energy. In this paper the possibility of self-polarized leptons at 45 and 80 GeV is investigated. Preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified ring are presented. Even in presence of errors a level of polarization useful for energy calibration seems not out of reach. However it is crucial to demonstrate that a energy measurement precision better than 100 KeV can be actually obtained. The last ring layout with 1 mm vertical beta at the IPs has been also considered. The large vertical beta in the IR quadrupoles makes the closed orbit very sensitive to their vertical misalignment and the orbit correction procedure challenging.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-MOT4H6

Export •

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

MOT4H7

Ideas for Siberian Snakes and Spin Rotators in Very High Energy e⁺e⁻ Rings

ion, solenoid, dipole, synchrotron

47

S.R. Mane
Convergent Computing, Shoreham, New York, USA

The high value of the radiated power in synchrotron radiation in very high energy e⁺e⁻ storage rings presents unique challenges for the design of Siberian Snakes and spin rotators in such machines. This paper presents some ideas which may lead to a feasible design of such devices. The idea is to employ solenoids interleaved with the arc dipoles, to yield a set of noncommuting spin rotations, which can rotate an initially vertical spin to any desired direction. The solenoids should be (approximately) optically transparent, and can be 'spin matched' to the ring using known procedures. Preliminary numerical studies indicate the design may be feasible.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-MOT4H7

Export •

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

WET1H4

Measurement of Beam Polarization and Beam Energy in One Device

ion, electron, photon, laser

168

N.Yu. Muchnoi
BINP SB RAS, Novosibirsk, Russia

Funding: Russian Science Foundation N 14-50-00080
Electron beam interaction with the monochromatic laser radiation produces scattered photons and electrons due to the Compton effect. Both types of scattered particles carry the information about the polarisation (if any) and the energy of initial electrons in the beam. This report is focused on the properties of the scattered electrons. After a bending magnet these electrons leave the beam and their X-Y space distribution is supposed to be measured by the 2D pixel detector. We show that if the electron beam vertical emittance is sufficiently small, the shape of this distribution is an ellipse. Measurement of the length of the X-axis of this ellipse allow to calibrate accurately the bending field integral seen by the beam. The distribution of the electrons within the ellipse depends on the initial beam polarisation, allowing to measure its degree and direction. So we propose a universal Compton polarimeter with a unique feature of precise calibration of the LEP-style beam energy spectrometer. The approach is thought to be useful for the future high-energy e⁺/e⁻ colliders, while the feasibility tests need to be performed on existing accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-WET1H4

Export •

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

THS2H3

Summary of Beam Instrumentation and Beam Diagnostics Session

ion, instrumentation, electron, feedback

220

H. Fukuma
KEK, Ibaraki, Japan

This report is a summary of the beam instrumentation and beam diagnostics session of the eeFACT2016 workshop.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-THS2H3

Export •

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