Depth Of Maximum Of Air-shower Profiles At The Pierre Auger Observatory. I. Measurements At Energies Above 1017.8ev

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Phase diagram of γ-butyrolactone-dimethyl-carbonate mixtures

Using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) at low temperatures we have determined a phase relation between γ-butyrolactone and dimethyl carbonate. Two polymorphs of γ-butyrolactone with a monotropic transformation and two polymorphs of dimethyl carbonate with an enantiotropic transformation induced by BL were observed. The diagram is characterised by an eutectic point for xDMC=0.12 and T=-57.5°C

Translational Diffusion in Mixtures of Imidazolium ILs with Polar Aprotic Molecular Solvents

Self-​diffusion coeffs. of cations and solvent mols. were detd. with 1H NMR in mixts. of 1-​n-​butyl-​3-​methylimidazolium (Bmim+) tetrafluoroborate (BF4-​)​, hexafluorophosphate (PF6-​)​, trifluoromethanesulfonate (TfO-​)​, and bis(trifluoromethylsulfonyl)​imide (TFSI-​) with acetonitrile (AN)​, γ-​butyrolactone (γ-​BL)​, and propylene carbonate (PC) over the entire compn. range at 300 K. The relative diffusivities of solvent mols. to cations as a function of concn. were found to depend on the solvent but not on the anion (i.e., IL)​. In all cases the values exhibit a plateau at low IL content (xIL < 0.2) and then increase steeply (AN)​, moderately (γ-​BL)​, or negligibly (PC) at higher IL concns. This behavior was related to the different solvation patterns in the employed solvents. In BmimPF6-​based systems, anionic diffusivities were followed via 31P nuclei and found to be higher than the corresponding cation values in IL-​poor systems and lower in the IL-​rich region. The inversion point of relative ionic diffusivities was found around equimolar compn. and does not depend on the solvent. At this point, a distinct change in the ion-​diffusion mechanism appears to take place

Acceptance tests and criteria of the ATLAS transition radiation tracker

The Transition Radiation Tracker (TRT) sits at the outermost part of the ATLAS Inner Detector, encasing the Pixel Detector and the Semi-Conductor Tracker (SCT). The TRT combines charged particle track reconstruction with electron identification capability. This is achieved by layers of xenonfilled straw tubes with periodic radiator foils or fibers providing TR photon emission. The design and choice of materials have been optimized to cope with the harsh operating conditions at the LHC, which are expected to lead to an accumulated radiation dose of 10 Mrad and a neutron fluence of up to 2 . 10(14) n/cm(2) after ten years of operation. The TRT comprises a barrel containing 52 000 axial straws and two end-cap parts with 320 000 radial straws. The total of 420 000 electronic channels (two channels per barrel straw) allows continuous tracking with many projective measurements (more than 30 straw hits per track). The assembly of the barrel modules in the US has recently been completed, while the end-cap wheel construction in Russia has reached the 50% mark. After testing at the production sites and shipment to CERN, all modules and wheels undergo a series of quality and conformity measurements. These acceptance tests survey dimensions, wire tension, gas-tightness, high-voltage stability and gas-gain uniformity along each individual straw. This paper gives details on the acceptance criteria and measurement methods. An overview of the most important results obtained to-date is also given

Muons In Air Showers At The Pierre Auger Observatory: Mean Number In Highly Inclined Events

We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62\ub0 and 80\ub0. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 10^19\u2009\u2009eV shower with a zenith angle of 67\ub0, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68\ub10.04\ub10.48(sys)) 710^7 muons with energies larger than 0.3 GeV. The logarithmic gain dlnN\u3bc/dlnE of muons with increasing energy between 4 710^18\u2009\u2009eV and 5 710^19\u2009\u2009eV is measured to be (1.029\ub10.024\ub10.030(sys))

Depth Of Maximum Of Air-shower Profiles At The Pierre Auger Observatory. Ii. Composition Implications

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