The 2003 Tracker Inner Barrel Beam Test

Before starting the CMS Silicon Strip Tracker (SST) mass production, where the quality control tests can only be done on single components, an extensive collection of activities aiming at validating the tracker system functionality has been performed. In this framework, a final component prototype of the Inner Barrel part (TIB) of the SST has been assembled and tested in the INFN laboratories and then moved to CERN to check its behaviour in a 25~ns LHC-like particle beam. A set of preproduction single-sided silicon microstrip modules was mounted on a mechanical structure very similar to a sector of the third layer of the TIB and read out using a system functionally identical to the final one. In this note the system setup configuration is fully described and the results of the test, concerning both detector performance and system characteristics, are presented and discussed

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Results of the tests of a CMS tracker inner barrel sub-system with a 25 ns beam

In May 2003, a beam test was performed to validate a subsystem of the CMS Tracker with a LHC-like beam. All final components, including detectors and fully optical readout, were assembled together on a sector of the third layer cylinder mechanical support. The system, with pre-production power supplies and DAQ, was taken into the CERN X5 beam area where, after a short period of commissioning stage it collected data samples over a two weeks test period. Data were analyzed and results concerning charge collection, noise, detector performance under different bias voltages, timing structure of the signal, and detector uniformity were obtained. The main system aspects as well as the DAQ and experimental setup are described and the detector performance is discussed

Search for Stop Pair Production in the Stop -> Chargino B and the Stop -> Neutralino Top Decay Modes

A search for stop pair production with the CMS detector in the decay modes stop -> chargino b (chargino -> W neutralino) and stop -> top neutralino is performed with a fast detector simulation. The signal final state contains two neutralinos, two W's and two b quarks. The resulting missing transverse energy, leptons and jets with large transverse momentum and tracks with large impact parameters allow the signal to be effectively separated from the standard model backgrounds. More work is required to reject the background from other supersymmetric production processes

Lifetime Based b-tagging with CMS

This paper provides a review of the main algorithms for inclusive b-tagging based on track impact parameter and secondary vertices. The performance of these algorithms is investigated for jets in different E_T and eta intervals and results are compared. The ORCA framework and the base 3-pixel layer Tracker geometry are used in these studies

Track impact parameter based b-tagging with CMS

This paper provides a review of the main algorithms for inclusive b-tagging based on track impact parameters. The performance of these algorithms is investigated for jets in different Pt and eta intervals and results are compared. Results are obtained in the ORCA reconstruction framework with full detector simulation. Investigation of the effects of misalignments are also shown

"ASTEROID: a new 64 channel ASIC for source follower based readout of the MIXS DEPFET arrays on BepiColombo"

ASTEROID is a new 64 channel ASIC developed to read out a DEPFET macropixel array. This sensor will be part of the MIXS instrument that will be used in the ESA's BepiColombo Mercury exploration mission. The detector will operate in an environment with high density of solar proton flux that will cause severe radiation damage and an increase of leakage current during mission lifetime. Given the relatively high value of the leakage current, a high speed readout and a proper cooling of the detector is needed in order to achieve the required energy resolution. The contribution of the readout electronics to the noise should be smaller than 10 electrons r.m.s. The foreseen pixel arrays are optimized for source follower readout. In this operating mode of the DEPFETs, the readout electronics is AC-coupled. This allows easy coping with non homogeneity of the pixel matrix and - most of all - an easy compensation of threshold voltage shifts of the DEPFET devices due to radiation damage. In order to achieve the low noise value required at short processing time, ASTEROID implements a trapezoidal weighting function, which represents the time-limited optimum filter for white series noise. This is the major electronics noise source at the foreseen readout speed. Measurements on a first prototype of the ASIC have shown the very satisfactory resolution of 147 eV on Mn-K alpha peak of Fe-55 with a readout time of approximately 1.2 mu s, that would lead, considering the settling time of the DEPFET, to a total processing time of 4.2 mu s. We present the experimental results of a first prototype that includes 4 analog channels and a new digital section for the generation of the timing signals of the circuit. This digital section is based on radiation-hardened dual-port memory cells and registers and has already been implemented to serve all the 64 channels foreseen for the final version of the ASIC

Radiation hardness of high resistivity n- and p-type magnetic Czochralski silicon

The luminosity upgrade of the CERN Large Hadron Collider (SLHC) imposes severe requirements on the radiation hardness of the tracking systems. The CERN RD50 collaboration as well as the Italian INFN SMART project (fifth commission) are focused on the study of new radiation hard materials and devices in view of this upgrade. Preliminary studies on irradiated high resistivity n- and p-type magnetic Czochralski silicon are described in this paper. Electrical characterization and microscopic defect studies were performed on a wide set of diodes made with both n- and p-type float zone and magnetic Czochralski silicon irradiated up to a nominal fluence of 3E15 cm2 1MeV equivalent neutrons. The annealing behavior was studied in detail and a first evaluation of the damage-related parameters is shown

Study of radiation damage induced by 24 GeV/c and 26 MeV protons on heavily irradiated MCz and FZ silicon detectors

The aim of this work is the development of radiation hard detectors for very high luminosity colliders. A growing interest has been recently focused on Czochralski silicon as a potentially radiation-hard material. We report on the processing and characterization of micro-strip sensors and pad detectors produced by ITC-IRST on n- and p-type magnetic Czochralski and float zone silicon. Part of thesamples has been irradiated using 24 GeV/c protons (CERN-Geneva), while another part has been irradiated with 26 MeV protons (FZK-Karlsruhe) up to a fluence of 5x1015 1 MeV-neutron-equivalent/cm2. All the samples have been completely characterized before and after irradiation. Their radiation hardness as a function of the irradiation fluence has been established in terms of breakdown voltage, leakage current and evaluating the more relevant mini-sensor parameter variation. Moreover, the time evolution of depletion voltage, leakage current and inter-strip capacitance has been monitored in order to study their annealing behavior and space charge sign inversion effects