A new fast-cycling system for AMS at ANU De Cesare, M.; Fifield, L.K.; Weisser, D.C. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
10/2015, Letnik:
361
Journal Article
Recenzirano
In order to perform higher precision measurements, an upgrade of the ANU accelerator is underway. Fast switching times on the low-energy side, with maximum settling times of 30ms, are achieved by ...holding the injector magnet field constant while changing the energy of the different isotopes by changing the pre-acceleration voltage after the ion source. Because ions of the different isotopes then have different energies before injection, it is necessary to adjust the strength and steering of the electrostatic quadrupole lens that focusses the beam before entry into the accelerator. First tests of the low-energy system will be reported. At the high energy end, a larger vacuum box in the analyzing magnet has been designed, manufactured and installed to allow the transport of differences in mass as large as 10% at constant terminal voltage. For the cases where more than one isotope must be transported to the detector an additional refinement is necessary. If the accelerator voltage is to be kept constant, then the trajectories of the different isotopes around both the analyzing and switching magnets must be modified. This will be achieved using bounced electrostatic steerers before and after the magnets. Simulations have been performed with the ion optic code COSY Infinity to determine the optimal positions and sizes of these steerers.
Tandem electrostatic accelerators often require the flexibility to operate at variety of terminal voltages to cater for various user needs. However beam transmission will only be optimal for a ...limited range of terminal voltages. This paper describes a focussing system that greatly expands the range of terminal voltages for optimal transmission. This is achieved by controlling the grathent of the entrance of the lowenergy tube providing an additional controllable focusing element. Up to 150 kV is applied to the fifth electrode of the first unit of the accelerator tube giving control of the tube entrance lens strength. Beam tests to confirm the efficacy of the lens have been performed. These tests demonstrate that the entrance lens control eliminates the need to short out sections of the tube for low terminal voltage operation.
Acute eosinophilic pneumonia (AEP) is a rare disease characteristically involving eosinophilic infiltration of lung parenchyma as well as fever, dyspnea, and coughing. A differentiation is made ...between primary and secondary AEP depending on the underlying etiology. Substances that most frequently cause secondary AEP are antibiotics, such as the lipopeptide daptomycin. This is a case report about a 69-year-old female patient who underwent antibiotic treatment with daptomycin for an infection of a knee prosthesis. During the treatment, signs of pneumonia developed and included the increased dependence on mechanical ventilation of the previously intubated patient, infiltrates on a chest X‑ray, fever, and an increase in serum inflammation markers. Proof of bacteria as an underlying pathogen was not possible. A thoracic computed tomography (CT) scan showed opacities that are commonly seen in interstitial lung disease. Termination of daptomycin treatment due to renal failure led to an improvement of pulmonary symptoms. Re-exposure to daptomycin resulted in a recurrence of the symptoms. The diagnostic criteria for AEP according to Uppal et al. include 1) current exposure to daptomycin, 2) dyspnea with increased oxygen requirements or necessity for mechanical ventilation, 3) new infiltrates on chest X‑ray or CT scan, 4) bronchoalveolar lavage with eosinophilia >25%, 5) improvement of clinical symptoms following daptomycin withdrawal, and 6) fever. With 5 out of the 6 criteria by Uppal et al. positive-an eosinophilia >25% being the only unmet criteria-an AEP induced by daptomycin was diagnosed. Withdrawal of daptomycin as well as high-dose cortisol bolus treatment led to a rapid recovery.
Austria still lacks a baby-take-home rate after assisted reproductive technologies (ART) and therefore an adequate quality management of ART.
This paper extrapolates data about births/infants after ...ART at the University Clinic of Obstetrics and Gynaecology (PMU/SALK) in Salzburg for Austria, especially in regard to multiple births/infants collected between 2000 and 2009.
On average 2 271 infants were born per year during the last 10 years. Among them, 76 infants (3.34% of all children) were born after ART. Of all children conceived by ART and born (759) at the University Clinic of Obstetrics and Gynaecology 368 are multiples. This is 48.5% of all children born after ART. 31.6% of all multiples born were conceived through ART.
The extrapolation of data concerning multiples results in 1 255 multiples/year after ART for Austria.
Without a baby-take-home rate, serious quality management of reproductive medicine is impossible. Online registration of deliveries and infants is the only adequate approach. The data of this statistical extrapolation from a single perinatal center not only provide a survey about the situation in Austria, but also support the claim of a quantitative (numbers) as well as qualitative (condition of infants) baby-take-home rate after ART.
This paper describes the electromagnetic and mechanical properties of a 150 MHz λ/4 , 3-gap structure with two loading elements, for the velocity range β=0.04–0.12 in the context of TEM-like λ/4 and ...λ/2 structures with multiple loading elements. A simple transmission lines model is presented and the results of Micro Wave Studio and simulations are discussed. The column of the multistub structures opens the opportunity to minimize current in locations allowing the exploitation of demountable joints and control the frequency splitting between the accelerating and other modes. These resonators are appropriate for the upgrade of the medium- and high-velocity sections of the ANU Heavy-Ion Accelerator Facility. Because of the broad velocity range for which such structures can be tailored, they can also be used in spallation neutron sources and rare isotope accelerators.
Rotary and displacement tuners are described for multistub superconducting rf resonators. The effectiveness of these tuners is made possible because the resonators have low currents between their ...outer conductors and tuner elements. Computer simulations and experimental data show that the devices provide a tuning range up to 100 kHz with a frequency resolution of about 1 Hz. As well, only a small driving force is required allowing use of a low-backlash drive mechanism. The use of the rotary tuner is limited to the resonators with two loading elements such as the 2-stub quarter wave resonator, the conventional split loop resonator, and the 2-stub, half wave resonator. The displacement tuner is more versatile and can be used for any TEM-like quarter wave resonator or half wave resonator resonators with two or more loading elements.
This paper describes a concept for superconducting resonators for the acceleration of ions in the velocity range β=v/c=0.015–0.04 . Such a resonator operates in λ/4 mode with three loading elements ...and so can be thought of as a triple quarter wave resonator (3-QWR) providing 4 accelerating gaps. The use of a column to support the three stubs provides a benefit beyond those of the two-stub design (2-QWR). In the 3-QWR, the rf mirror currents in the walls surrounding the stubs need only travel through 45° instead of the 90° in the 2-QWR thus further reducing the current in the demountable joints. As in the 2-QWR, the shape of the column allows control of the frequency splitting between the accelerating and other modes. The copper structure is designed to be coated by a thin superconducting film of niobium or lead for operation at 4.3 K. The particular device reported here operates at 150 MHz with an optimum β of 0.04. Its outer cylinder is the same size and shape as for the 2-QWR structure reported previously, in order to minimize construction and cryostat costs. A simple transmission line model is presented and the results of microwave studio and other numerical analyses are discussed. The 3-QWR resonators are appropriate for the upgrade of the low-velocity sections of the ANU Heavy Ion Accelerator Facility and other heavy ion accelerator boosters.
A balloonborne gondola for a comprehensive study of polar stratospheric clouds (PSCs) was launched on 25 January 2000 near Kiruna/Sweden. Besides an aerosol composition mass spectrometer, the gondola ...carried optical particle counters, two backscatter sondes, a hygrometer, and several temperature and pressure sensors. A mountain wave induced PSC was sampled between 20 and 23 km altitude. Strongly correlated PSC particle properties were detected with the different instruments. A large variability of particle types was measured in numerous PSC layers, and PSC development was followed for about two hours. Liquid ternary PSC layers were found at temperatures near the ice frost point. A large fraction of the sampled cloud layers consisted of nitric acid trihydrate (NAT) particles with a molar ratio H2O:HNO3 close to 3 at temperatures near and below the equilibrium temperature TNAT. The median radius of the NAT particle size distribution was between 0.5 and 0.75 μm at concentrations around 0.5 cm−3. Below the NAT layers and above TNAT, thin cloud layers containing a few large particles with radii up to 3.5 μm coexisted with smaller solid or liquid particles. The molar ratio in this region was found to be close to two.
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