A Method to Improve the Neutrino Energy Reconstruction in LArTPCs

Precision measurements of the neutrino oscillation parameters allow to determine the potential violation of CP-symmetry in the leptonic sector. If the violation of CP-symmetry in the leptonic sector can be experimentally confirmed, this could become the preferred explanation in the Standard Model for the matter-antimatter asymmetry of the universe. The Deep Underground Neutrino Experiment (DUNE), which is being built by the Fermi National Accelerator Laboratory (FNAL) in the USA, aims to perform these measurements of the neutrino oscillation parameters using Liquid Argon Time Projection Chamber (LArTPC) detectors. Four massive multi-kt Far Detectors (FDs) are deployed together with a Near Detector (ND) that uses the same detector technology as the FDs. As a consequence of the high-intensity neutrino beam and the short distance to the neutrino source the ND will need the ability to disentangle multiple overlapping events that happen within a single readout cycle. This is achieved with a LArTPC following the ArgonCube concept, which was developed at the University of Bern. The ArgonCube concept divides the detector volume into a number of identical, optically isolated and electrically isolated Time Projection Chamber (TPC) modules. The optical isolation reduces the pile-up of the scintillation light and allows for better localization of light signals. The ND will need to measure the neutrino energy because neutrino oscillations occur as a function of the neutrino energy. Neutrons emerging from the neutrino interaction vertex can carry away more than 25 % of the neutrino energy, which is missed by applying the calorimetric method, because neutral particles are not reconstructed in LArTPCs. I have determined the bias and the uncertainty of the reconstructed neutrino energy due missed primary neutrons, based on simulations using the GENIE event generator. At the DUNE beam spectrum, primary neutrons will be involved in about 80 % of the neutrino-argon interactions. In those events with primary neutrons involved, a mean energy corresponding to ∼10 % of the parent neutrino’s kinetic energy is carried away by primary neutrons, and the relative uncertainty on the reconstructed neutrino energy can exceed 13 %. I have developed a method to identify neutrons in LArTPCs by secondary charged particles that are produced if a neutron interacts with an argon nucleus. These neutrons appear as detached energy deposits, which prevents a trivial assignment to the correct interaction vertex, given the high event multiplicity at the ND site. Therefore, I further developed a method to assign detached energy deposits to neutrino interaction verices, exploiting the fast response of the light-readout systems. With a timing resolution at the O (1) ns, the light-readout systems easily allow to separate the light signals of individual events, which have a mean separation time of 179 ns. If the presented methods are used to veto neutrino interactions with primary neutrons, then the respective uncertainty on the reconstructed neutrino energy can be reduced to < 10 %

First Operation of a Resistive Shell Liquid Argon Time Projection Chamber -- A new Approach to Electric-Field Shaping

We present a new technology for the shaping of the electric field in Time Projection Chambers (TPCs) using a carbon-loaded polyimide foil. This technology allows for the minimisation of passive material near the active volume of the TPC and thus is capable to reduce background events originating from radioactive decays or scattering on the material itself. Furthermore, the high and continuous electric resistivity of the foil limits the power dissipation per unit area and minimizes the risks of damages in the case of an electric field breakdown. Replacing the conventional field cage with a resistive plastic film structure called 'shell' decreases the number of components within the TPC and therefore reduces the potential points of failure when operating the detector. A prototype liquid argon (LAr) TPC with such a resistive shell and with a cathode made of the same material was successfully tested for long term operation with electric field values up to about 1.5 kV/cm. The experiment shows that it is feasible to successfully produce and shape the electric field in liquefied noble-gas detectors with this new technology.Comment: 13 page

Christian Koller im Interview mit Selma Knecht und Patrick McEvily, SRF News, 08.05.2024: Das Erbe der 1968er: Ein Rückblick – Die Protestkultur an Schweizer Universitäten

In den USA haben sie begonnen, inzwischen kommt es in mehreren Ländern zu propalästinensischen Demonstrationen an Universitäten – auch in der Schweiz. In welcher Tradition stehen diese? Der Experte ordnet ein

Associations between weather, air quality and moderate extreme cancer-related mortality events in Augsburg, Southern Germany

While many authors have described the adverse health effects of poor air quality and meteorological extremes, there remain inconsistencies on a regional scale as well as uncertainty about the single and joint effects of atmospheric predictors. In this context, we investigated the short-term impacts of weather and air quality on moderate extreme cancer-related mortality events for the urban area of Augsburg, Southern Germany, during the period 2000–2017. First, single effects were uncovered by applying a case-crossover routine. The overall impact was assessed by performing a Mann–Whitney U testing scheme. We then compared the results of this procedure to extreme noncancer-related mortality events. In a second step, we found periods with contemporaneous significant predictors and carried out an in-depth analysis of these joint-effect periods. We were interested in the atmospheric processes leading to the emergence of significant conditions. Hence, we applied the Principal Component Analysis to large-scale synoptic conditions during these periods. The results demonstrate a strong linkage between high-mortality events in cancer patients and significantly above-average levels of nitrogen dioxide (NO2) and particulate matter (PM2.5) during the late winter through spring period. These were mainly linked to northerly to easterly weak airflow under stable, high-pressure conditions. Especially in winter and spring, this can result in low temperatures and a ground-level increase and the accumulation of air pollution from heating and traffic as well as eastern lateral advection of polluted air. Additionally, above-average temperatures were shown to occur on the days before mortality events from mid-summer through fall, which was also caused by high-pressure conditions with weak wind flow and intense solar radiation. Our approach can be used to analyse medical data with epidemiological as well as climatological methods while providing a more vivid representation of the underlying atmospheric processes

Gender differences in paediatric patients of the swiss inflammatory bowel disease cohort study.

PURPOSE: Gender differences in paediatric patients with inflammatory bowel disease (IBD) are frequently reported as a secondary outcome and the results are divergent. To assess gender differences by analysing data collected within the Swiss IBD cohort study database since 2008, related to children with IBD, using the Montreal classification for a systematic approach. METHODS: Data on gender, age, anthropometrics, disease location at diagnosis, disease behaviour, and therapy of 196 patients, 105 with Crohn's disease (CD) and 91 with ulcerative or indeterminate colitis (UC/IC) were retrieved and analysed. RESULTS: THE CRUDE GENDER RATIO (MALE : female) of patients with CD diagnosed at &lt;10 years of age was 2.57, the adjusted ratio was 2.42, and in patients with UC/IC it was 0.68 and 0.64 respectively. The non-adjusted gender ratio of patients diagnosed at ≥10 years was 1.58 for CD and 0.88 for UC/IC. Boys with UC/IC diagnosed &lt;10 years of age had a longer diagnostic delay, and in girls diagnosed with UC/IC &gt;10 years a more important use of azathioprine was observed. No other gender difference was found after analysis of age, disease location and behaviour at diagnosis, duration of disease, familial occurrence of IBD, prevalence of extra-intestinal manifestations, complications, and requirement for surgery. CONCLUSION: CD in children &lt;10 years affects predominantly boys with a sex ratio of 2.57; the impact of sex-hormones on the development of CD in pre-pubertal male patients should be investigated

Paradoxical response of plasma atrial natriuretic hormone to pericardiocentesis in cardiac tamponade

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26804/1/0000360.pd

Climate change and small island developing states

Despite their heterogeneity, small island developing states (SIDS) are recognized as being particularly at risk to climate change, and, as they share numerous common traits, the United Nations recognizes them as a special group. SIDS have been quite vocal in calling attention to the challenges they face from climate change and advocating for greater international ambition to limit global warming. Here, we unpack factors that are helpful in understanding the relationship between climate change and SIDS through a review of studies that span disciplines and methodologies. We assess patterns of hazards, exposure, and vulnerability; impacts and risks; awareness and knowledge; adaptation planning and implementation; mitigation; loss and damage; and climate justice to provide an overarching review of literature on climate change and SIDS