| Paper |
Title |
Other Keywords |
Page |
| TUPBB03 |
Performance of the FCC-ee Polarimeter |
electron, laser, photon, scattering |
157 |
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- N.Yu. Muchnoi
BINP SB RAS, Novosibirsk, Russia
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Inverse Compton scattering is the classical way to measure the electron beam polarization. Eligibility of the approach at high energy domain has been demonstrated by LEP, HERA and SLD experiments. Fast measurement of beam polarization allows to apply the resonant depolarization technique for precise beam energy determination. The distinctive feature of the FCC-ee polarimeter is the registration of scattered electrons along with scattered photons. Polarimeter is designed to measure the transverse polarization of the non-colliding pilot bunch with 1 % accuracy every second. Furthermore the same apparatus allows to measure the beam energy, longitudinal beam polarization (if any) and transverse beam positions/sizes at the place of installation.
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| DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB03
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| About • |
paper received ※ 18 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 |
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| TUPBB04 |
Resonant Depolarization at Z and W at FCC-ee |
synchrotron, resonance, ECR, collider |
165 |
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- I. Koop
BINP SB RAS, Novosibirsk, Russia
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Both future 100 km in circumference electron-positron colliders CEPC and FCC-ee need know beams energies with the extreme precision of 1-2 ppm. This can be done only with the help of Resonant Depolarization (RD) technique. Still, some beam parameters of these machines, like energy spread and damping decrements, are so high near 80 GeV per beam, that it is required special consideration and tricks to overcome the difficulties. The author has written simple spin tracking code, which simulates main features of the RD process in presence of continuous energy diffusion due to synchrotron radiation fluctuations. It was shown by this study, that the applicability of the RD method is limited by the effect of widening of a width of the central peak of the spin precession spectrum when the synchrotron tune is chosen too low, say below 0.05. In this case spin precession lost its resonant nature due to overlap of the wide central spectrum peak with nearby synchrotron side bands. Dependencies of the spectrum peaks width from various beam parameters and a new RD-procedure recipe are presented.
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| DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB04
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| About • |
paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 |
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| WEXAA01 |
High Precision Experiments in the J/psi, Psi(2S) and Tau Sector |
resonance, scattering, detector, storage-ring |
179 |
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- I.B. Nikolaev
BINP SB RAS, Novosibirsk, Russia
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High precision experiments in charmonium sector require beam energy calibration. VEPP-4M storage ring with energy measurement by resonant depolarization (RD) method provided high precision mass measurement of J/ψ- and ψ(2S)- mesons with KEDR detector with accuracy 2×10-6. This narrow resonances can be used for calibration of energy scale of other accelerators such as BEPC-II or future Super Charm-Tau Factories equipped with Compton backscattering (CBS) energy measurement system.
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| DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXAA01
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| About • |
paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 |
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| WEXAA02 |
Polarization Issues at CEPC |
resonance, wiggler, booster, electron |
182 |
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- S.A. Nikitin
BINP SB RAS, Novosibirsk, Russia
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We study a possibility of obtaining transversely polarized electron-positron beams at the CEPC collider. At the beam energy of 45 GeV, this requires the use of the special wigglers to speed up the radiative self-polarization process. A numerical estimation of the depolarizing effect of the collider field errors is made, taking into account the modulation of the spin precession frequency by synchrotron oscillations. In addition, we consider an alternative possibility of obtaining polarization by accelerating the polarized particles in the booster and then injecting them into the main ring. This option saves time spent on the polarization process, and is also crucial for obtaining longitudinal polarization.
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| DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXAA02
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| About • |
paper received ※ 19 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 |
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| WEXAA04 |
Ideas for Longitudinal Polarization at the Z/W/H/top Factory |
solenoid, acceleration, booster, positron |
190 |
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- I. Koop, A.V. Otboev
BINP SB RAS, Novosibirsk, Russia
- Yu.M. Shatunov
Budker INP & NSU, Novosibirsk, Russia
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Different schemes for getting the longitudinal polarization at FCC-ee are considered. Depolarization rates for rings with spin rotators are evaluated and methods of acceleration of polarized beams in a booster synchrotron are proposed.
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| DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXAA04
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| About • |
paper received ※ 10 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 |
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