117898455
Program of the Beijing TcF feasibility study
We present the status of the Tau/charm factory design study in China. The report consists of a detailed description of the different phases of the study and the local organization established to carry it out. A list of workshops intended to regularly review the status of the design study is included.
120808467
Travelling wave accelerating structure design for TESLA positron injector linac
A modified cup-like TW accelerating structure for TESLA Positron Pre-Accelerator (PPA) is designed by optimizing the structure geometry and by changing the iris thickness cell by cell in a section. This structure has high shunt-impedance and a large iris radius to meet with the requirements of high gradient and large transverse acceptance. The beam dynamics in the structure with the optimum solenoid focus held are studied. A satisfactory positron beam transmission and the beam performance at the PPA output have been obtained. In this paper the accelerating structure design is described in detail and the results are presented. (C) 2000 Elsevier Science B.V. All rights reserved.
108288058
Beam dynamics studies on the 100 MeV/100 kW electron linear accelerator for NSC KIPT neutron source
We designed a 100 MeV/100 kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the basis of subcritical assembly. Beam dynamics studies have been conducted to reach the design requirements (E = 100 MeV, P = 100 kW, dE/E < 1% for 99% particles). In this paper, we will present the progress of the design and the dynamic simulation results. For high intensity and long beam pulse linear accelerators, the BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at a low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced downstream of the 1st accelerating section; the unwanted particles will be collimated there.
122385836
Study on the characteristics of linac based THz light source
There are many methods based on linac for THz radiation production. As one of the options for the Beijing Advanced Light, an ERL test facility is proposed for THz radiation. In this test facility, there are 4 kinds of methods to produce THz radiation: coherent synchrotron radiation (CSR), synchrotron radiation (SR), low gain FEL oscillator, and high gain SASE FEL. In this paper, we study the characteristics of the 4 kinds of THz light sources.
109931583
The experimental study on beam-photoelectron instability in BEPC
A vertical coupled bunch instability explained as the photoelectron instability (PEI) was observed in the photon factory at KEK. To further investigate the instability, the experiments on the PEI have been carried out in Beijing Electron Positron Collider (BEPC) with the collaboration between MEP, China and KEK, Japan. Many interesting phenomena have been observed for different sets of parameters.
56291250
BEPC status and plans
BEPC operation status over the past few years with the results in exciting physics and integrated luminosity enhancement are summarized. The status of the luminosity upgrade project is described. The future plans on the tau-charm factory and the new generation light source are presented.
208854095
Measurements of the top-quark mass using charged particle tracking
We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb{sup -1} of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9{sub -8.5}{sup +9.5} (stat) {+-} 2.9 (syst) GeV/c{sup 2}, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5{sub -8.9}{sup +8.8} (stat) {+-} 3.8 (syst) GeV/c{sup 2}. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 {+-} 6.3 (stat) {+-} 2.6 (syst) GeV/c{sup 2}.
118662023
Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics
A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.
67817261
Critical Height for the Destabilization of Solar Prominences: Statistical Results from STEREO Observations
At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we
8106823
THE X-RAY ORIGIN OF HERBIG AeBe SYSTEMS: NEW INSIGHTS
We present a statistical study of the X-ray emission toward 22 Herbig AeBe stars (HAEBE) using the Chandra archive. We probe the origin of the X-rays toward Herbig stars: are they intrinsic?This question is addressed by correlations between the physical stellar properties and the X-ray emission. There is a weak correlation between the continuum radio emission at λ = 3.6 cm and L X, which suggests that the X-ray emission depends upon the source. On the other hand, no correlation was found with the stellar rotational period, but that only excludes solar-like magnetic activity as the origin of the X-rays. Most importantly, the X-ray luminosity of HAEBE has a different distribution from that of T Tauri stars, suggesting that X-ray emission from an unseen late-type star companion can be ruled out with an 80% confidence level. This implies that the HAEBE must have magnetic activity. In addition, we report the observation of five sources for the first time, in three detections.
119181888
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.