Search for eV Sterile Neutrinos - The Stereo Experiment

In the recent years, major milestones in neutrino physics were accomplished at nuclear reactors: the smallest neutrino mixing angle $\theta_{13}$ was determined with high precision and the emitted antineutrino spectrum was measured at unprecedented resolution. However, two anomalies, the first one related to the absolute flux and the second one to the spectral shape, have yet to be solved. The flux anomaly is known as the Reactor Antineutrino Anomaly and could be caused by the existence of a light sterile neutrino participating in the neutrino oscillation phenomenon. Introducing a sterile state implies the presence of a fourth mass eigenstate, global fits favour oscillation parameters around $\sin^2({2\theta}) \approx 0.09$ and $\Delta m^2 \approx 1\,\mathrm{eV}^2$. The Stereo experiment was built to finally solve this puzzle. It is one of the first running experiments built to search for eV sterile neutrinos and takes data since end of 2016 at ILL Grenoble (France). At a short baseline of 10 metres, it measures the antineutrino flux and spectrum emitted by a compact research reactor. The segmentation of the detector in six target cells allows for measurements of the neutrino spectrum at multiple baselines. An active-sterile flavour oscillation could be unambiguously detected, as it distorts the spectral shape of each cell's measurement differently. This contribution gives an overview on the Stereo experiment, along with details on the detector design, detection principle and the current status of data analysis.Comment: Proceedings for EPS-HEP 2017, European Physical Society Conference on High Energy Physics (5-12 July 2017), Venice, Ital

Die Datennahmekette des Double Chooz Experiments und ihre Komponenten - Eigenschaften der Photomultiplier und der Frontend-Elektronik

The Double Chooz experiment is a reactor antineutrino experiment searching for a non-vanishing value of the neutrino mixing angle θ13; it will commence operation in fall 2010. The scintillation light of the neutrino events is detected by a total of 390 photomultiplier tubes, and the subsequent data acquisition chain consists of Splitter Boxes, Frontend Electronics, the Trigger Board and Flash ADCs. This Diploma thesis describes certain properties of the photomultiplier tubes and their measurements, such as linearity characteristics at high light levels and afterpulse behaviour with respect to charge and time. The e ect of afterpulsing on the Double Chooz experiment has been estimated by converting the measured results, together with the trigger conditions, into a simulation. In order to allow for tests of the Double Chooz data acquistion chain in advance, Frontend Electronics, Flash ADCs and a 30 litre acrylic cylinder filled with the Double Chooz target scintillator have been added to the existing photomultiplier test facility at MPIK Heidelberg. The measurements of the gain of the Frontend Boards are discussed in this thesis. Furthermore the preparation and installation of the acrylic vessel is described and the detection of scintillation light of rst events produced by muons is presented

PMT Test Facility at MPIK Heidelberg and Double Chooz Super Vertical Slice

Proceedings supplement for conference poster at Neutrino 2010, Athens, Greece

Transit Time and Charge Correlations of Single Photoelectron Events in R7081 PMTs

During the calibration phase of the photomultiplier tubes (PMT) for the Double Chooz experiment the PMT response to light with single photoelectron (SPE) intensity was analysed. With our setup we were able to measure the combined transit time and charge response of the PMT and therefore we could deconstruct and analyse all physical effects having an influence on the PMT signal. Based on this analysis charge and time correlated probability density functions were developed to include the PMT response in a Monte Carlo simulation.Comment: minor changes by referee reques

Preservice Middle School Mathematics Teachers’ Development in Formative Assessment

International audienceThe study was conducted to investigate preservice middle school mathematics teachers’ professional development in formative assessment practices they plan to implement in classrooms. Basic qualitative research method was employed in this study. Incomplete and Improper Lesson Plan Task developed by the researchers was implemented to 47 2nd year, 37 3rd year, and 27 4th year preservice middle school mathematics teachers. Findings of the study indicated that participants who took measurement and assessment course and methods of teaching courses (3rd year and 4th year preservice teachers) emphasized integrating formative assessment strategies more than 2nd year preservice teachers. None of the participants mentioned to give opportunity to students to assess themselves or provide feedback to the students in order to enhance their learning. 3rd year and 4th year preservice teachers were also more successful in detecting the improperness of the lesson plan

Transit Time and Charge Correlations of Single Photoelectron Events in R7081 PMTs

During the calibration phase of the photomultiplier tubes (PMT) for the Double Chooz experiment the PMT response to light with single photoelectron (SPE) intensity was analysed. With our setup we were able to measure the combined transit time and charge response of the PMT and therefore we could deconstruct and analyse all physical effects having an influence on the PMT signal. Based on this analysis charge and time correlated probability density functions were developed to include the PMT response in a Monte Carlo simulation.Comment: minor changes by referee reques

Investigation of the Supply Chain Strategy Effects on Substantive Legal Framework and Problems of Iraqi Local Authorities` Activity in the Social Sphere

This article considers the legal norms regulating the activities of local governments in the field of social services at the federal, regional and municipal levels of government, the activities of municipal social services to provide social assistance and support and issues relating to the separation of powers between state authorities and local governments in social services. In recent years, many social problems have arisen or worsened, resulting in a decline in the population of Iraq. According to the latest data, August - December 2009, the number of Iraqis decreased by 30.4 thousand people. In comparison with the same months last year, Iraqis have died more than 11.5 thousand. Across the country, the number of deaths on the number of births was 2.6 times. Therefore, an active local social policy in the field of social services is one of the most important tasks of municipal development. It is at the municipal level that it is easier to identify social problems, determine the circle of people in need of social assistance, develop the system of social services, improve the quality of social services provided, thereby increasing the efficiency of social services at the local level

Afterpulse Measurements of R7081 Photomultipliers for the Double Chooz Experiment

We present the results of afterpulse measurements performed as qualification test for 473 inner detector photomultipliers of the Double Chooz experiment. The measurements include the determination of a total afterpulse occurrence probability as well as an average time distribution of these pulses. Additionally, more detailed measurements with different light sources and simultaneous charge and timing measurements were performed with a few photomultipliers to allow a more detailed understanding of the effect. The results of all measurements are presented and discussed

Gonad maturity and gonadal somatic index of blue swimming crab Portunus pelagicus harvested from Spermonde Archipelago, South Sulawesi, Indonesia

Reproductive biology is one of the biological aspects that needed to formulate responsible management of blue swimming crab (BSC). The crab is one of the commercial fisheries commodities in South Sulawesi, Indonesia. Presently no information on the reproductive biology of this crab from Spermonde Archipelago, Sout Sulawesi. Therefore, the study aimed to analyze and compare gonad maturity stage(GMS)andgonadalsomaticindex(GSI)oftheBSCcaughtonthreeecosystemsnamelycoralreef,seagrass,andmangrovein Salemo Island, Spermonde Archipelago. GMS and GSI were analyzed descriptively for five months from March to July 2015. Results indicate there was a difference in GMS of the BSC caught in mangroves, seagrass, and coral reef. Generally, mangrove was dominated by immature BSC with GMS I and GMS II, while the BSC caught in the seagrass and coral reef BSC were dominantly mature and spawn GMS III, IV, and V. GSI BSC caught in mangrove ecosystem are smaller than GSI BSC caught in seagrass and coral reef ecosystems. Seagrass and coral reef ecosystems suitable for development no-take zone of the BSC