A Dual Triangle Timing Circuit for Improved Performance of 4-Quadrant H-Bridge Switches

Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. This upgrade requires power supplies with maximum outputs of {+-}180V/{+-}65A, with current bandwidths of 5k Hz and with slew rates of min to max current in 1ms. For seamless operation around zero current and voltage, we use continuous switching on both sides of the bridge. Although the straightforward way of coordinating the switching on both sides of the bridge can be accomplished with one triangle timing wave and one voltage reference, we have found that using two triangle waves yields a switching coordination that effectively doubles the frequency of the differential ripple on the load and allows for better filtering of the output ripple

К вопросу борьбы с обледенением стальных тросов

The understanding of biological processes, e.g. related to cardio-vascular disease and treatment, can significantly be improved by numerical simulation. In this paper, we present an approach for a multiscale simulation environment, applied for the prediction of in-stent re-stenos is. Our focus is on the coupling of distributed, heterogeneous hardware to take into account the different requirements of the coupled sub-systems concerning computing power. For such a concept, which is an extension of the standard multiscale computing approach, we want to apply the term Distributed Multiscale Computing

Gauge-Theory Heavy Muons: An Experimental Search

We have observed 1522 neutrino events with a μ- secondary and 8 events with a μ+ secondary from a beam consisting mostly of neutrinos. The μ+ events are consistent in number and kinematic properties with beam contamination by ν̅ μ. This experiment sees no evidence for production of heavy positively charged leptons. Assuming a coupling constant equal to the universal Fermi constant and a branching ratio to muons B=0.3, our 90% confidence lower limit corresponds to MY+≳8.4 GeV/c^2

System overview for the multi-element corrector magnets and controls for the Fermilab Booster

To better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron, a new package of six corrector elements has been designed, incorporating both normal and skew orientations of dipole, quadrupole, and sextupole magnets. The devices are under construction and will be installed in 48 locations in the Booster accelerator. Each of these 288 corrector magnets will be individually powered. Each of the magnets will be individually controlled using operator programmed current ramps designed specifically for each type of Booster acceleration cycle. This paper provides an overview of the corrector magnet installation in the accelerator enclosure, power and sensor interconnections, specifications for the switch-mode power supplies, rack and equipment layouts, controls and interlock electronics, and the features of the operator interface for programming the current ramps and adjusting the timing of the system triggers

Mass Limit on a Positively Charged Heavy Muon

We report a preliminary search for a positively charged lepton (Y+) coupled directly to the μ- and νμ (i.e., muon number = + 1). Using the production process νμ+N→Y++anything, we have looked for the μ+ from the decay Y+→μ++νμ+νμ. The expected number of μ+ events is given as a function of the heavy-lepton mass, the branching fraction to muons, and the heavy-lepton coupling. For typical gauge-theory predictions, we obtain the 90% confidence limit MY>2 GeV/c^2

Experimental Comparison of Neutrino and Muon Velocities

The velocities of neutrinos and muons originating from π+ and K+ decays have been compared using the California Institute of Technology-Fermilab detector in a narrow-band neutrino beam. A time-of-flight comparison between positive muons and neutrinos, as indicated by the final-state negative muons in neutrino interactions, yields |βν-βμ|<~0.4×10-3 (99% confidence level). We assume that |1-βμ|<10-5 for these muons