Abstract
The Siberian ring source of photons (SKIF) is a new 3 GeV
fourth-generation synchrotron light source being developed by the
Budker Institute of Nuclear Physics (BINP). A beam loss monitoring
...system is necessary to ensure its reliable commissioning and
operation. Two types of beam loss monitors will be installed in the
SKIF: 5 fiber-based Cherenkov beam loss monitors (CBLMs) for the
linac and transfer lines and 128 scintillator-based beam loss
monitors (SBLMs) for the storage ring. Sophisticated electronic
equipment is employed to use these monitors in different modes of
SKIF operation. The paper describes the design of the SKIF beam loss
monitoring system based on numerical simulations and experimental
studies.
Abstract
The work addresses the use of electron beam produced by the
linear induction accelerator to generate terahertz radiation pulses
of 100 MW power level based on a free electron laser scheme. ...The
beam parameters required for efficient generation are given. The
features of transverse beam dynamics when transporting the beam
through the linac are investigated. Emphasis is put on the electron
injector which geometry and operation parameters mainly determine
the beam characteristics at the linac exit. Most of the possible
factors contributing to the beam emittance gain in the accelerator
are considered. The obtained analytical estimates are compared to
the numerical simulation results. The experimental results on
compressing and transporting the beam having the electron energy of
5 MeV and the current of 1 kA in the transport system of free
electron laser are presented.
Abstract
As the injector of the new fourth-generation SKIF
synchrotron light source at the BINP SB RAS (Novosibirsk, Russia),
the linear accelerator will provide a 200 MeV electron beam. A
precise ...measurement of the beam is very important for the control of
the linac and even the entire light source. A set of diagnostic
instruments for tuning the linac and measuring the beam parameters
starting from the electron RF gun to the output of accelerator has
been designed. The instrumentation should cover the dynamic
diagnostic range of 0.6 to 200 MeV and a beam duration from the
initial 100 ps to 3 ps at the output of the accelerator. The set
includes eight fluorescent screens to measure beam transverse size,
two Cherenkov probes and RF-cavity sensors to record beam duration,
a dipole magnetic spectrometer to measure energy and energy spread,
a Faraday cup (FC) and fast current transformers (FCTs) to measure
beam charge current, and beam position monitors (BPMs) to check the
beam position. This paper aims to give an overview of the beam
instrumentation and briefly describes the design and parameters of
each diagnostic system. The results of numerical and dynamics
simulations of some of the instruments are briefed. Possible
scenarios of linac tuning are discussed.
The efficiency of the injection from the linear accelerator into the damping ring of the injection complex at Budker Institute of Nuclear Physics has been experimentally studied. The estimations of ...the injection efficiency are in good agreement with the measurements. A method for increasing the efficiency of injection from the linear accelerator into the damping ring has been implemented in order to enhance the productivity of the injection complex. To this end, the RF cavity has been replaced and the RF frequency was changed from 700 to 11 MHz. Recent measurements have shown a two-fold increase in the productivity. Besides that, the behavior of the longitudinal profile of a bunch during the first turns in the damping ring and the dependence of the profile on the beam current have been studied.
The ratio of the electron and muon widths of the J/ psi J/ psi meson has been measured using direct J/ psi J/ psi decays in the KEDR experiment at the VEPP-4M electron-positron collider. The result ...Gamma e+e-(J/ psi )/ Gamma mu + mu -(J/ psi )=1.0022 plus or minus 0.0044 plus or minus 0.0048(0.65%) is in good agreement with the lepton universality. The experience collected during this analysis will be used for J/ psi J/ psi lepton width determination with up to 1% accuracy.
To improve operation parameters (S/N ratio, dynamics range, time resolution, etc.) of picosecond streak tubes, the traditional P20/P43 phosphor screens can be replaced by the others (P46/P47) having ...much faster decay time of the luminescence output. We provide comparative dynamic measurements of the home-made phosphor screens inside the picosecond PIF-01 streak tubes under illumination of their photocathodes by a single picosecond laser pulse or a train of picosecond laser pulses. We show that the shortest measured decay time for made-in-Russia phosphor screens (Y
3
Al
5
O
12
:Ce) is close to several hundreds of nanoseconds not only at a half-intensity level but also at a level of 10
−3
and even smaller. Furthermore, the photoelectron-to-photon conversion factor is not drastically smaller than in the traditional phosphor materials. This means that application of streak tubes supplied with fast-response phosphor screens may substantially improve the tube capabilities in the accumulation mode, and this is very important for time-resolved diagnostics of electron bunches in accelerators, where continuous accumulation of repetitive signals is needed.
A new high precision measurement of the J/ψ- and ψ′-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the ...absolute calibration of the beam energy. The following mass values have been obtained: MJ/ψ=3096.917±0.010±0.007 MeV,Mψ′=3686.111±0.025±0.009 MeV. The relative measurement accuracy has reached 4×10−6 for J/ψ and 7×10−6 for ψ′, approximately 3 times better than in the previous precise experiments.
Measurement of parameters Anashin, V V; Aulchenko, V M; Baldin, E M ...
Physics letters. B,
05/2012, Letnik:
711, Številka:
3-4
Journal Article
Recenzirano
We report the final results of a study of the psi ( 3770 ) meson using a data sample collected with the KEDR detector at the VEPP-4M electron-positron collider. The data analysis takes into account ...interference between the resonant and nonresonant D D macr production, where the latter is related to the nonresonant part of the energy-dependent form factor F D . The vector dominance approach and several empirical parameterizations have been tried for the nonresonant F D N R ( s ) . Our results for the mass and total width of psi ( 3770 ) are M = 3779.2 - 1.7 + 1.8 - 0.7 + 0.5 - 0.3 + 0.3 MeV , Gamma = 24.9 - 4.0 + 4.6 - 0.6 + 0.5 - 0.9 + 0.2 MeV , where the first, second and third uncertainties are statistical, systematic and model, respectively. For the electron partial width two possible solutions have been found: ( 1 ) Gamma e e = 154 - 58 + 79 - 9 + 17 - 25 + 13 eV , ( 2 ) Gamma e e = 414 - 80 + 72 - 26 + 24 - 10 + 90 eV . Our statistics are insufficient to prefer one solution to another. The Solution (2) mitigates the problem of non- D D macr decays but is disfavored by potential models. It is shown that taking into account the resonance-continuum interference in the near-threshold region affects resonance parameters, thus the results presented cannot be directly compared with the corresponding PDG values obtained ignoring this effect.
A high-precision determination of the main parameters of the psi ( 2 S ) resonance has been performed with the KEDR detector at the VEPP-4M e + e - collider in three scans of the psi ( 2 S ) - psi ( ...3770 ) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of the psi ( 2 S ) we obtained the mass value M = 3686.114 plus or minus 0.007 plus or minus 0.011 - 0.012 + 0.002 MeV and the product of the electron partial width by the branching fraction into hadrons Gamma e e B h = 2.233 plus or minus 0.015 plus or minus 0.037 plus or minus 0.020 keV . The first and second uncertainties are statistical and systematic, respectively. The third uncertainty quoted is an estimate of the model dependence of the result due to assumptions on the interference effects in the cross section of the single-photon e + e - annihilation to hadrons explicitly considered in this work. Implicitly, the same assumptions were employed to obtain the charmonium leptonic width and the absolute branching fractions in many experiments. Using the result presented and the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of the psi ( 2 S ) : Gamma e e = 2.282 plus or minus 0.015 plus or minus 0.038 plus or minus 0.021 keV , Gamma = 296 plus or minus 2 plus or minus 8 plus or minus 3 keV . These results are consistent with and more than two times more precise than any of the previous experiments.
We report results of a search for narrow resonances in e super(+e) super(-) annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e ...super(+e) super(-) collider. The upper limit on the leptonic width of a narrow resonance inline image has been obtained (at 90% C.L.).
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