49 research outputs found

    Analysis of test beam data taken with a prototype of TPC with resistive Micromegas for the T2K Near Detector upgrade

    Full text link
    In this paper we describe the performance of a prototype of the High Angle Time Projection Chambers (HA-TPCs) that are being produced for the Near Detector (ND280) upgrade of the T2K experiment. The two HA-TPCs of ND280 will be instrumented with eight Encapsulated Resistive Anode Micromegas (ERAM) on each endplate, thus constituting in total 32 ERAMs. This innovative technique allows the detection of the charge emitted by ionization electrons over several pads, improving the determination of the track position. The TPC prototype has been equipped with the first ERAM module produced for T2K and with the HA-TPC readout electronics chain and it has been exposed to the DESY Test Beam in order to measure spatial and dE/dx resolution. In this paper we characterize the performances of the ERAM and, for the first time, we compare them with a newly developed simulation of the detector response. Spatial resolution better than 800 ÎŒm{\mu \rm m} and dE/dx resolution better than 10% are observed for all the incident angles and for all the drift distances of interest. All the main features of the data are correctly reproduced by the simulation and these performances fully fulfill the requirements for the HA-TPCs of T2K

    Characterization of Charge Spreading and Gain of Encapsulated Resistive Micromegas Detectors for the Upgrade of the T2K Near Detector Time Projection Chambers

    Full text link
    An upgrade of the near detector of the T2K long baseline neutrino oscillation experiment is currently being conducted. This upgrade will include two new Time Projection Chambers, each equipped with 16 charge readout resistive Micromegas modules. A procedure to validate the performance of the detectors at different stages of production has been developed and implemented to ensure a proper and reliable operation of the detectors once installed. A dedicated X-ray test bench is used to characterize the detectors by scanning each pad individually and to precisely measure the uniformity of the gain and the deposited energy resolution over the pad plane. An energy resolution of about 10% is obtained. A detailed physical model has been developed to describe the charge dispersion phenomena in the resistive Micromegas anode. The detailed physical description includes initial ionization, electron drift, diffusion effects and the readout electronics effects. The model provides an excellent characterization of the charge spreading of the experimental measurements and allowed the simultaneous extraction of gain and RC information of the modules

    Measurements of the ΜΌ\nu_{\mu} and ΜˉΌ\bar{\nu}_{\mu}-induced Coherent Charged Pion Production Cross Sections on 12C^{12}C by the T2K experiment

    Get PDF
    We report an updated measurement of the ΜΌ\nu_{\mu}-induced, and the first measurement of the ΜˉΌ\bar{\nu}_{\mu}-induced coherent charged pion production cross section on 12C^{12}C nuclei in the T2K experiment. This is measured in a restricted region of the final-state phase space for which pÎŒ,π>0.2p_{\mu,\pi} > 0.2 GeV, cos⁥(ΞΌ)>0.8\cos(\theta_{\mu}) > 0.8 and cos⁥(Ξπ)>0.6\cos(\theta_{\pi}) > 0.6, and at a mean (anti)neutrino energy of 0.85 GeV using the T2K near detector. The measured ΜΌ\nu_{\mu} CC coherent pion production flux-averaged cross section on 12C^{12}C is (2.98±0.37(stat.)±0.31(syst.)+0.49−0.00(Q2 model))×10−40 cm2(2.98 \pm 0.37 (stat.) \pm 0.31 (syst.) \substack{ +0.49 \\ -0.00 } \mathrm{ (Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}. The new measurement of the ΜˉΌ\bar{\nu}_{\mu}-induced cross section on 12C^{12}{C} is (3.05±0.71(stat.)±0.39(syst.)+0.74−0.00(Q2 model))×10−40 cm2(3.05 \pm 0.71 (stat.) \pm 0.39 (syst.) \substack{ +0.74 \\ -0.00 } \mathrm{(Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}. The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions

    Measuring proliferation in breast cancer: practicalities and applications

    Get PDF
    Various methods are available for the measurement of proliferation rates in tumours, including mitotic counts, estimation of the fraction of cells in S-phase of the cell cycle and immunohistochemistry of proliferation-associated antigens. The evidence, advantages and disadvantages for each of these methods along with other novel approaches is reviewed in relation to breast cancer. The potential clinical applications of proliferative indices are discussed, including their use as prognostic indicators and predictors of response to systemic therapy

    Measurements of the ΜΌ and ÎœÂŻÎŒ -induced coherent charged pion production cross sections on C12 by the T2K experiment

    Get PDF
    We report an updated measurement of the Îœ ÎŒ -induced, and the first measurement of the ÂŻ Îœ ÎŒ -induced coherent charged pion production cross section on 12 C nuclei in the Tokai-to-Kamioka experiment. This is measured in a restricted region of the final-state phase space for which p ÎŒ , π > 0.2     GeV , cos ( Ξ ÎŒ ) > 0.8 and cos ( Ξ π ) > 0.6 , and at a mean (anti)neutrino energy of 0.85 GeV using the T2K near detector. The measured Îœ ÎŒ charged current coherent pion production flux-averaged cross section on 12 C is ( 2.98 ± 0.37 ( stat ) ± 0.31 ( syst ) + 0.49 − 0.00 ( Q 2   model ) ) × 10 − 40     cm 2 . The new measurement of the ÂŻ Îœ ÎŒ -induced cross section on 12 C is ( 3.05 ± 0.71 ( stat ) ± 0.39 ( syst ) + 0.74 − 0.00 ( Q 2   model ) ) × 10 − 40     cm 2 . The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions

    Limits to simplified calculation of uncut chip thickness in milling

    No full text
    Modelling of forces and temperatures for mechanical cutting processes is mainly based on the prevailing local uncut chip geometry. In this context, most researchers use a simplified equation for calculating the uncut chip thickness in milling processes, which neglects the tool movement in feed direction and simplifies the chip thickness. The simplified equation can be easily evaluated, but also adds errors to the calculation results. These errors are typically neglected without knowledge of their exact size. However, the resulting error is dependent on the cutting parameters like cutting speed, tool feed and radial tool engagement and can be very large. In order to quantify the resulting error for different cutting conditions, a novel approach for a more precise calculation of the uncut chip thickness is presented in this paper. Using this new calculation model the uncut chip thickness is determined for industrial relevant cutting parameters and tool dimensions in the first step. The second step includes the direct comparison of the calculated values to the simplified calculation. In this way, the resulting error is illustrated for different cutting situations, mainly focusing on full slot milling and the contact area, where the workpiece surface is generated. As a result, limits for the application of the simplified engagement calculation are presented. In case the limits are exceeded, a more complex and more accurate calculation of the uncut chip thickness has to be used

    The Jak1 SH2 domain does not fulfill a classical SH2 function in Jak/STAT signaling but plays a structural role for receptor interaction and up-regulation of receptor surface expression

    No full text
    The presence of a Src homology 2 (SH2) domain sequence similarity in the sequence of Janus kinases (Jaks) has been discussed since the first descriptions of these enzymes. We performed an in depth study to determine the function of the Jak1 SH2 domain. We investigated the functionality of the Jak1 SH2 domain by stably reconstituting Jak1-defective human fibrosarcoma cells U4C with endogenous amounts of Jak1 in which the crucial arginine residue Arg466 within the SH2 domain has been replaced by lysine. This mutant still binds to the receptor subunits gp130 and OSMR. Moreover, the SH2 R466K mutation does not affect the subcellular distribution of Jak1 as assessed by cell fractionation and confocal microscopy of cells expressing endogenous levels of non-tagged or a yellow fluorescent protein (YFP)-tagged Jak1-R466K, respectively. Likewise, the signaling capacity of Jak1 was not affected by this point mutation. However, we found that the SH2 domain is structurally important for cytokine receptor binding and surface expression of the OSMR
    corecore