110696864
Rf noise tolerances at the SSC
We apply the diffusion in action theory developed by Dome, Krinsky, and Wang to the determination of SSC rf noise tolerances using the emittance-doubling time as a criterion. We present results for white amplitude and white phase noise, noise measured from a HP synthesizer and from a SLAC PEP klystron. We also derive a scaling law for white amplitude and phase noise that allows one to understand the dependence of the diffusion process on the rf frequency. Lastly we qualitatively discuss the implementation of feedback loops to reduce rf noise.
15693839
Self-consistent computation of electromagnetic fields and phase space densities for particles on curved planar orbits
We discuss our progress on the self-consistent calculation of the 4D phase space density (PSD) and electromagnetic fields in a Vlasov-Maxwell formulation. We emphasize coherent synchrotron radiation (CSR) from arbitrary curved planar orbits, with shielding from the vacuum chamber, but space charge forces are naturally included. Our focus on the Vlasov equation will provide simulations with lower numerical/statistical noise than standard PIC methods, and will allow the study of issues such as emittance degradation and microbunching due to space charge and CSR in bunch compressors. The fields excited by the bunch are computed in the lab frame from a new double integral formula. The field formula is derived from retarded potentials by changes of variables. It is singularity-free and requires no computation of retarded times. Ultimately, the Vlasov equation will be integrated in beam frame coordinates using our method of local characteristics. As an important intermediate step, we have developed a "self-consistent Monte Carlo algorithm", and a corresponding parallel code. This gives an accurate representation of the source and will help in understanding the PSD support. In addition we have (1) studied carefully a 2D phase space Vlasov analogue and (2) derived an improved expression of the field of a 1D charge/current distribution which accounts for the interference of different bends and other effects usually neglected. Bunch compressors will be emphasized.
2396816
Progress on a Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits
We report on our progress in the development of a fully self-consistent Vlasov treatment of coherent synchrotron radiation (CSR) effects on particle bunches traveling on arbitrary planar orbits. First we outline our Vlasov approach and the approximation we are currently studying. Then we discuss recent numerical results for a benchmark model studied extensively with codes by several authors.
55035317
COMPARISON OF 1D AND 2D CSR MODELS WITH APPLICATION TO THE FERMI @ ELETTRA BUNCH COMPRESSORS
We compare our 2D mean field (Vlasov-Maxwell) treatment of coherent synchrotron radiation (CSR) effects with 1D approximations of the CSR force which are commonly implemented in CSR codes. In our model we track particles in 4D phase space and calculate 2D forces [1]. The major cost in our calculation is the computation of the 2D force. To speed up the computation and improve 1D models we also investigate approximations to our exact 2D force. As an application, we present numerical results for the Fermi{at}Elettra first bunch compressor with the configuration described in [1].
189808711
Summary of Coherent Theory and Simulations Session
There were two types of talks which we attempt to summarize. Section 2 discusses the analytical talks and Section 3 the simulation talks. We hope that at least our summary will have the flavor of the session and serve as a reasonable pointer to papers in the proceedings and elsewhere. We take this opportunity to thank the participants of this session for making it an interesting one. The major emphasis in this session was on codes and we have tried to give an overview of basic computational strategies in Section 3 before highlighting the talks.
122076282
Deflection of GeV particle beams by channeling in bent crystal planes of constant curvature
121802001
Evaluation of prototype silicon drift detectors
Abstract Silicon drift detectors, of two elementary designs, have been fabricated and tested using β electrons and light pulses. Drift of electrons within the detectors has been observed over distances up to about 8 mm with high efficiency. Results are presented, some of which identify important design parameters of such devices.
15585431
Measurements of the W boson mass and trilinear gauge boson couplings at the Tevatron
We present measurements of the W boson mass at the Tevatron based on $W \to \mu \nu$ events collected by CDF and $W \to e \nu$ events observed by D0 in Run Ib (1994--95). The W boson mass measured in the preliminary CDF analysis is 80.43 \pm 0.10 (stat) \pm 0.12 (syst) GeV/c^2. The D0 measured value is 80.44 \pm 0.10 (stat) \pm 0.07 (syst) GeV/c^2. We also describe measurements of the trilinear gauge boson couplings. The limits obtained on the WW\gamma and WWZ anomalous couplings from a combined D0 analysis using $W\gamma$, $WW \to \ell \nu \ell^\prime \nu^\prime$, and $WW/WZ \to e \nu jj$ production are: -0.30 < \Delta\kappa < 0.43, -0.20 < \lambda < 0.20, and -0.52 < \Delta g^Z_1 < 0.78, for a dipole form factor scale of 2 TeV. Improved limits have been obtained by combining these results with the limits derived from the LEP experiments.
121961325
Simulation of b-jet identification in a non-magnetic detector☆
Abstract The simulation of a silicon microstrip detector at the center of the D0 detector at the Fermilab Tevatron collider is described. The efficiency of a silicon vertex detector for identifying b-quark jets in a “non-magnetic” detector such as D0 is investigated. For a position resolution of 10 μm the gluon/b-jet rejection factor is estimated to be 25 for a b-jet efficiency of 25%. The detection of top quarks in the presence of background from high p T W boson production is studied.
17092028
CP Violation Results from D0
We present results on CP violation from approximately 2.8 fb^{-1} of data collected by the D0 Experiment at the Fermilab Tevatron. The results presented are: (i) an improved measurement of the B_s^0 CP-violating phase from a flavor-tagged analysis of B_s^0 --> J/\psi \phi decays; (ii) a search for direct CP violation in B^{+-} --> J/\psi K^{+-} (\pi^{+-}) decays from a measurement of the charge asymmetry A_{CP}(B^{+-} --> J/\psi K^{+-}); and (iii) a search for indirect CP violation from searches for anomalous charge asymmetries in semileptonic B_s^0 decays.
121294791
Background rates in silicon detectors used in uranium calorimeters
Abstract Ion-implanted silicon diode detectors have been used to establish counting rates from radioactive decays of uranium. The measurements allow the estimation of background counting rates in uranium-silicon calorimeters used in high energy physics experiments.