The Argon Dark Matter Experiment (ArDM)

The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nuclei. These events producing a recoiling nucleus will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and will be commissioned on surface at CERN. Here we describe the detector concept and give a short review on the main detector components.Comment: Proceedings of 4th Patras workshop (DESY) on Axions, Wimps and Wisps (4 pages, 4 figures

Grain boundary assisted photocurrent collection in thin film solar cells

The influence of absorber grain boundaries on the photocurrent transport in chalcopyrite based thin film solar cells has been calculated using a two dimensional numerical model. Considering extreme cases, the variation in red response is more expressed than in one dimensional models. These findings may offer an explanation for the strong influence of buffer layer preparation on the spectral response of cells with small grained absorbers

Generation-dependent charge carrier transport in Cu(In,Ga)Se 2/CdS/ZnO thin-film solar-cells

The following article appeared in Journal of Applied Physics 113.4 (2013): 044515 and may be found at http://scitation.aip.org/content/aip/journal/jap/113/4/10.1063/1.4788827Cross section electron-beam induced current (EBIC) and illumination- dependent current voltage (IV) measurements show that charge carrier transport in Cu(In,Ga)Se2 (CIGSe)/CdS/ZnO solar-cells is generation-dependent. We perform a detailed analysis of CIGSe solar cells with different CdS layer thicknesses and varying Ga-content in the absorber layer. In conjunction with numerical simulations, EBIC and IV data are used to develop a consistent model for charge and defect distributions with a focus on the heterojunction region. The best model to explain our experimental data is based on a p+ layer at the CIGSe/CdS interface leading to generation-dependent transport in EBIC at room temperature. Acceptor-type defect states at the CdS/ZnO interface cause a significant reduction of the photocurrent in the red-light illuminated IV characteristics at low temperatures (red kink effect). Shallow donor-type defect states at the p+ layer/CdS interface of some grains of the absorber layer are responsible for grain specific, i.e., spatially inhomogeneous, charge carrier transport observed in EBIC

Number of comorbidities and their impact on perioperative outcome and costs - a single centre cohort study

AIMS OF THE STUDY Multimorbidity is a growing global health problem, resulting in an increased perioperative risk for surgical patients. Data on both the prevalence of multimorbidity and its impact on perioperative outcome are limited. The American Society of Anesthesiologists (ASA) classification uses only the single most severe systemic disease to define the ASA class and ignores multimorbidity. This study aimed to assess the number and type of all anaesthesia-relevant comorbidities and to analyse their impact on outcome and hospital costs. METHODS This cohort study is nested in the ClassIntra® validation study and includes only patients enrolled at the University Hospital of Basel. Approximately 30 patients per surgical discipline undergoing any type of in-hospital surgery were followed up until hospital discharge to record all intra- and postoperative adverse events. In addition, the type and severity of all perioperatively relevant comorbidities were extracted from the electronic medical record according to a predefined list. The primary endpoint was the number of all anaesthesia-relevant comorbidities by ASA class. Using structural equation models, the direct and indirect effects of comorbidities on costs were estimated after adjustment for the ASA class and further relevant confounders and mediators. RESULTS Of 320 enrolled patients, 27 were ASA I (8%), 150 ASA II (47%), 116 ASA III (36%) and 27 ASA IV (8%). The median number of comorbidities per patient was 5 (range 0-18), this number significantly increasing with higher ASA class: 1 comorbidity (95% CI 0.0-2.0) in ASA I, 4 comorbidities (3.8-4.2) in ASA II, 9 (8.1-9.9) in ASA III and 12 (10-14) in ASA IV patients. Independent of ASA class, each additional comorbidity increased hospital costs by EUR 1,198 (95% CI 288-2108) with almost identical proportions of direct and indirect effects. The number of anaesthesia-relevant comorbidities also increased postoperative complications and postoperative length of hospital stay. CONCLUSIONS Multimorbidity in perioperative patients is highly prevalent and has a relevant impact on hospital costs, independent of the ASA class. Incorporating multimorbidity into the ASA classification might be warranted to improve its predictive ability and support adequate reimbursement

Junction formation by Zn(O,S) sputtering yields CIGSe-based cells with efficiencies exceeding 18%

In an effort to reduce the complexity and associated production costs of Cu(In,Ga)Se2 (CIGSe)-based solar cells, the commonly used sputtered undoped ZnO layer has been modified to eliminate the requirement for a dedicated buffer layer. After replacing the ZnO target with a mixed ZnO/ZnS target, efficient solar cells could be prepared by sputtering directly onto the as- grown CIGSe surface. This approach has now been tested with high-quality lab- scale glass/Mo/CIGSe substrates. An efficiency of 18.3% has been independently confirmed without any post-deposition annealing or light soaking