Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays

Average charged multiplicities have been measured separately in $b$, $c$ and light quark ($u,d,s$) events from $Z^0$ decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of $b$ and light quark events, and reconstructed charmed mesons were used to select $c$ quark events. We measured the charged multiplicities: $\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.})$, $\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ^{+0.41}_{-0.36}(\rm{syst.})$ $\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ^{+0.38}_{-0.37}(\rm{syst.})$, from which we derived the differences between the total average charged multiplicities of $c$ or $b$ quark events and light quark events: $\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})^{+0.36}_{-0.30}(\rm{syst.})$ and $\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})^{+0.30}_{-0.29}(\rm{syst.})$. We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Geothermal reservoir assessment: Cove Fort-Sulphurdale Unit. Final report, September 1977-July 1979

Three exploratory geothermal wells were drilled in the Cove Fort-Sulphurdale geothermal resource area in southwestern Utah to obtain new subsurface data for inclusion in the US DOE's geothermal reservoir assessment program. Existing data from prior investigations which included the drilling of an earlier exploratory well at the Cove Fort-Sulphurdale area was also provided. Two of the wells were abandoned before reaching target depth because of severe lost circulation and hole sloughing problems. The two completed holes reached depths of 5221 ft. and 7735 ft., respectively, and a maximum reservoir temperature of 353/sup 0/F at 7320 ft. was measured. The deepest well flow was tested at the rate of 47,000 lbs/h with a wellhead temperature of 200/sup 0/F and pressure of 3 psig. Based upon current economics, the Cove Fort-Sulphurdale geothermal resource is considered to be sub-commercial for the generation of electrical power. A synopsis is given of the exploratory drilling activities and results containing summary drilling, testing, geologic and geochemical information from four exploratory geothermal wells

Three-dimensional finite-element computations of the transient response of components typical of a reactor structure. [SADCAT code]

A structural analysis, finite-element code SADCAT has been developed to compute the elastoplastic response of thin-walled structural members undergoing rapid, large displacements in three-dimensional space. A convected-coordinate technique permits a simplified description of large displacements and rotations. The computational procedure consists of a lumped-mass, explicit numerical scheme suited to the nonlinear path-dependent material behavior. Code predictions have been compared with analytical calculations and published experimental data, and the correlations validate the capability of the code to provide reliable predictions for three-dimensional shell-type structure

Numerical simulation of an equipment hatch for a steel containment vessel to loading beyond the design basis

A preliminary analysis of the sealing deformations of a large equipment hatch with a pressure-seated gasket due to overpressurization was performed. An axisymmetric finite element analysis of the penetration sleeve revealed that its surface can undergo large rotations; values for sealing surface rotation of 7/sup 0/ were computed. Estimates for the order of magnitude of leakage due to the sealing surface rotation were made. 10 refs., 7 figs., 1 tab