Abstract
The backscattering of laser radiation by a relativistic
electron beam is a widely used method for measuring the spin
polarization of electrons. We consider again the properties of the
...scattering process paying special attention to recoil electrons.
Based on this consideration we propose the concept of the Compton
polarimeter in which, in addition to all the polarization
components, it becomes possible to accurately measure the energy and
other parameters of the electron beam. To demonstrate the
capabilities of the method we conduct a Monte Carlo simulations of
the polarimeter developed for the FCC-ee project.
Laser backscattering was implemented as a tool for accurate beam energy measurement at BES-III and VEPP-2000 electron-positron colliders. Here we summarize the experience obtained during these ...experiments. In fact, this report is the revised and updated version of our previous report on the same topic 1.
Laser backscattering was implemented as a tool for accurate beam energy measurement at three of the five existing electron-positron colliders. The present report summarizes the experience obtained ...during these experiments.
The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of CO laser photons on the electron beam is used. The relative ...systematic uncertainty of the beam energy determination is estimated as 610 super(-5). It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.
Status of laser polarimeter at VEPP-4M Blinov, V.E.; Bedareva, T.V.; Zakharov, S.A. ...
Journal of instrumentation,
08/2020, Letnik:
15, Številka:
8
Journal Article
Recenzirano
Laser polarimeter facility at VEPP-4M accelerator is designed to calibrate the beam energy by resonance depolarization method in the energy region of the Υ-meson. The laser trigger and laser ...polarization control system has been upgraded. A new water-cooled vacuum mirror is being developed.
A method for circular e−/e+ accelerator beam energy measurement is proposed. A coordinate of an electron (or a positron) in a focusing magnetic spectrometer built in a circular accelerator depends on ...its energy, two spectrometer parameters, and the circulating beam energy. The spectrometer parameters can be determined using minimum electron energies from Compton backscattering with two laser wavelengths, and a coordinate detector for photons. The photon detector is calibrated separately at well-known beam energy. The VEPP-4M collider has appropriate equipment for the method implementation: built-in focusing magnetic spectrometer, Compton calibration system with two lasers and a photon coordinate detector. Thus, the proposed technique could be implemented with minimum efforts; tests and further upgrade are planned. The beam energy can be defined with expected uncertainty better than 10−4.
The tagging system of the KEDR detector is a symmetrical focusing magnetic spectrometer for electrons and positrons scattered at small angles; it is embedded into the lattice of the VEPP-4M collider ...and intended for two-photon processes study. It measures scattered electron energy with resolution ΔE/E0=0.03% 0.6% (E0 is the beam energy). For precise energy scale calibration two methods are used: tagging of bremsstrahlung electron/positron by the photon energy measured by BGO calorimeter, and direct calibration using Compton backscattering spectrum edge. This report covers design and current status of the calibration system.
The beam energy measurement system (BEMS) for the upgraded Beijing electron–positron collider BEPC-II is described. The system is based on measuring the energies of Compton back-scattered photons. ...The relative systematic uncertainty of the electron and positron beam energy determination is estimated as 2×10−5. The relative uncertainty of the beam's energy spread is about 6%.
A laser polarimeter at the VEPP-4M storage ring is being developed for the beam energy calibration by the resonant depolarization method in the future high-precision measurements of the Υ meson ...masses with the KEDR detector. The status of the laser polarimeter and first energy measurements at 4.1 GeV with an accuracy of 50 keV is described.
Tau mass measurement at BES-III Achasov, M.N.; Mo, X.H.; Muchnoi, N.Yu ...
EPJ Web of Conferences,
2019, Letnik:
212
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
A scan of the threshold region of the process
e
+
e
−
→ τ
+
τ
−
with integrated luminosity about 140 pb
−1
was performed with the BES-III detector at the BEPC-II collider in order to measure the ...τ-lepton mass. The beam energy was determined by the Compton backscattering method. To verify the measurement accuracy scans of the
J
/ψ and ψ
′
resonances were performed.
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