We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam ...bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10^{-29} e cm.
This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron ...(COSY) storage ring in order to control both the precession rate (≈121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of σ=0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by ν(s)=γG (γ is the ...Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently precess at a frequency of ≈120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10^{-8}, and to 1×10^{-10} for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance ...condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up–down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.
In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that thexandychromaticities vanish and the maximizing of the lifetime of in-plane ...polarization (IPP) for a0.97−GeV/cdeuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbon-target polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.
Summary Non-return valves (NRVs) are designed to avoid backflow of infusion fluid against the designated direction of flow (DDF) when more than one infusion is delivered via one venous access. We ...tested in vitro whether NRVs reliably prevent flow against the DDF at clinically relevant low flow rates. Since catheter-related infections caused by the infusion of contaminated fluids represent a relevant problem in patient care, we tested whether NRVs preclude bacterial contamination of infusions proximal to the NRVs and thus might play a role in preventing healthcare-associated infections. Additionally, the incidence of bacterial contamination of drips and infusion fluids in our intensive care unit (ICU) was quantified. In vitro , a low flow against the DDF of ten examples each of five different NRV models was applied and the integrity for fluid and transmigration of three different indicator micro-organisms was tested. Second, we investigated whether contamination of intravenous infusion tubing collected from patients treated on our ICU occurred. Largely independent from the model, 40% of the tested NRVs were not leak-tight for fluids when a pressure against the DDF was built up slowly. In 30%, bacteria migrated against the DDF and were detected proximal to the valve. In 6.7% of the tubing samples collected from ICU patients we detected bacterial contamination. In conclusion, contamination of drips is a relevant problem on ICU. NRVs neither reliably prevent backflow of fluids nor serve as micro-organism filters. Therefore they cannot be recommended as a way of reducing healthcare-associated infections.
The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design ...calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1–2MHz at the COoler SYnchrotron COSY at Jülich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe.
In Germany there is considerable variability in the organizational forms of intensive-care medicine. We present economical data that arose during the reorganization of an intensive care unit with the ...implementation of the continuous presence of a trained intensivist. The unit was changed from an intensive-observational unit managed by four surgical departments without continuous presence of a trained intensivist to an interdisciplinary surgical intensive care unit managed by the Department of Anaesthesia in co-operation with the surgical departments with the continuous presence of trained intensivists.
Measurement of costs for personnel, medical equipment and external services, revenues, length of hospital stay and complications of cardiac surgical patients.
Per year costs for personnel increased by approximately euro240,000, while expenses for medical equipment were reduced by euro245,000. In all, 466 hospital days were saved by the reduction in the length of hospital stay, providing capacity for 22 additional cardiac surgical cases. In addition, the presence of trained intensivists made it possible to provide care for more severely ill patients, which gained approximately 100 additional case-mix points and increased the hospital's revenues by more than euro300,000. Emergency readmission to the intensive care unit was reduced by 17%. The number of patients requiring renal replacement therapy and those developing non-occlusive mesenteric ischaemia was substantially reduced.
In addition to the medical advantages, staffing the intensive care unit with trained intensivists 24 h a day was of appreciable economical benefit.
This study was undertaken in order to elucidate the differences between various planes of measurement and Doppler techniques (pulsed‐ vs. continuous‐wave Doppler) across the aortic valve to estimate ...cardiac output. In 45 coronary artery bypass patients, cardiac output was measured each time using four different Doppler techniques (transverse and longitudinal plane, pulsed‐ and continuous‐wave Doppler) and compared with the thermodilution technique. Measurements were performed after induction of anaesthesia and shortly after arrival in the intensive care unit. Optimal imaging was obtained in 91% of the patients, in whom a total of 82 measurements of cardiac output were performed. The respective mean (SD) areas of the aortic valve were 3.77 (0.71) cm2 in the transverse plane and 3.86 (0.89) cm2 in the longitudinal plane. A correlation of 0.87 was found between pulsed‐wave Doppler cardiac output and the thermodilution technique in either transverse or longitudinal plane. Correlation coefficients of 0.82 and 0.84 were found between thermodilution cardiac output and transverse and longitudinal continuous‐wave Doppler cardiac output, respectively. Although thermodilution cardiac output is a widely accepted clinical standard, transoesophageal Doppler echocardiography across the aortic valve offers adequate estimations of cardiac output. In particular, pulsed‐wave Doppler cardiac output in both the transverse and longitudinal plane provides useful data.
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