2,252 research outputs found
Measurement of Drift Velocity in the CMS Barrel Muon Chambers at the CMS Magnet Test Cosmic Challenge
No full textThis note reports the results of the analysis performed on the data collected by the CMS Barrel Muon system during the Magnet Test-Cosmic Challenge, aimed to study the Drift Tube chambers behavior at the nominal value of the CMS magnetic field. In particular, the analysis is devoted to the study of the drift velocity in the various equipped regions of the apparatus. It is shown that the drift velocity is significantly affected by the presence of a residual magnetic field in the chamber volume only in the innermost stations, MB1, of Wheel+2; where the maximal variation inside the chamber is of 4 percent, which does not prevent a good functionality of the DT trigger even in this most critical region
Performance of A Parallel-plate Volume Calorimeter Prototype
No full textAn iron/gas parallel plate volume calorimeter prototype, working in the avalanche mode, has been tested using electrons of 20 to 150 GeV/c momentum with high voltages varying from 5400 to 5600 V (electric fields ranging from 36.0 to 37.3 kV/cm), and a gas mixture of CF4/CO2 (80%/20%). The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte Carlo predictions. Agreement between data and simulation allows the calculation of the expected performance of a full size calorimeter
Offline calibration procedure of the CMS Drift Tube detectors
No full textAbbiendi, G., Amapane, N., Battilana, C., Bellan, R., Biallass, P., Biasotto, M., Bolognesi, S., Calderon Tazon, A., Cavallo, F.R., Cepeda, M., Cerminara, G., De La Cruz, B., Diez Pardos, C., Fernandez Bedoya, C., Fernandez Menendez, J., Fouz Iglesias, M.C., Frangenheim, J., Giunta, M., Gresele, A., Guiducci, L., Gulmini, M., Hoepfner, K., Josa Mutuberria, M.I., Lacaprara, S., Marcellini, S., Martinez Ruiz Del Arbol, P., Maselli, S., Masetti, G., Meneguzzo, A.T., Mila, G., Molina Insfran, J.A., Passaseo, M., Perrotta, A., Puerta Pelayo, J., Reithler, H., Ronchese, P., Rovelli, T., Santaolalla Camino, J., Teyssier, D., Travaglini, R., Trocino, D., Vanini, S., Ventura, S., Vilela Pereira, A., Zanetti, M
Radiation hardness test of ceramic parallel-plate chambers with gammas up to 1 Grad
No full textResults on the radiation resistance test of ceramic parallel-plate chambers after nearly 1 Grad gamma irradiation are presented
First results from pion beam test of an iron/gas calorimeter based on ceramic parallel plate chambers
No full textA prototype module of an iron/gas calorimeter based on parallel plate chambers, has been tested using high energy electrons and pions, at two high voltages, using CF4/CO2 (80/20) at atmospheric pressure, The collected charge and energy resolution have been measured as a function of the beam energy for both electrons and pions and compared with Monte Carlo predictions
Performance of an iron/gas sampling calorimeter based on ceramic parallel-plate chambers
No full textA prototype module of an iron-gas sampling calorimeter based on parallel-plate chambers, full-size depth has been tested using high-energy muons, electrons and pions. The module was equipped with more than 1000 active cells read out individually. Experimental measurements at the test beam and their comparison with Monte-Carlo simulations are presented, Expected performance for a calorimeter suitable for low-angle regions in LHC experiments are derived
PPC's (parallel plate chambers) y su aplicación en calorimetría a bajo angulo en experimentos en el LHC
No full textIn the LHC working conditions especific detector requirements are fast response, high rate capability and radiation resistance. This is particularly important for detectors in the low angle regions such as the Very Forward Hadron Calorimeter ( VF ) of CMS , located at 11 m from the interaction point and covering the pseudorapidity region between 3 and 5. The major goals of this calorimeters are to improve the measured of the transverse energy ( Et) and the missing transverse energy ( Etmiss) ( important for Higgs searches, Top-quark physics, SUSY searches, etc) and the detection and reconstruction of forward jets characteristics of some importants process (such the TeV jets coming from the WW(ZZ) fusion Higgs production mechanism ). The requirements for this calorimeter are a moderate energy resolution and an adequate segmentation for forward jet tagging and reconstruction are needed. The purpose of this thesis is to show that calorimeters based on the Parallel Plate Chambers ( PPC. - Gaseous detector with planar electrodes working in avalanche mode) technology are feasible and adequate for very forward calorimetry in LHC experiments. We have construct diferent PPC cells and study its characteristics: time resolution; efficiency; radiation hardness; spark probability, etc. The tests show that this chambers are very fast (few ns, time resolution < 250 ps), radiation hard , sparking hard, have a high rate capability and a low spark probability and, using a apropiate gas mixture, a high efficiency . Therefore this chambers could be used for trigger and time of fly measurements in LHC experiments. We have construct several prototype calorimeters that was exposed to muon, electron and pion beams with energy range from 35 to 375 GeV. The prototypes was tested using different high voltages and two gases: pure CO2 and a mixture of CF4/CO2 (80/20). The collected charge was measured as a function of the high voltage and of the particle energy . We have also measured the energy resolution of this prototypes. A Monte-Carlo simulation, based on GEANT and our own simulation of the avalanche mode of operation, capable to reproduce the experimental data was developed, allowing to make predictions of the expected performance of a full size calorimeter. Using this Monte-Carlo model we have study the contribution of a low angle calorimetry, based on PPCs to the physics in CMS. We have study the physics performance expectations for the forward jets detection and reconstruction and for the Et and Etmiss reconstruction . We have also studied the effect of low energy neutrons coming from the pile-up background events in the CMS VF/PPC calorimeter. The effect over the calorimeter of the pile-up background events in terms of the irradiation and activation was calculated using our Monte-Carlo model. The test was made at SPS (at CERN ) test beam lines , ( H2 , H4 , X5 ), at ciclotron MGC-20 at ATOMKI (Debrece, Hungary), Serpukov and ITEP (Moscow. Russia) in the frame of the RD5 , RD37 and the CMS experiment
Electron beam test of an iron/gas calorimeter based on ceramic parallel plate chambers
No full textThe baseline option for the very forward calorimetry in the CMS experiment is an iron/gas calorimeter based on parallel plate chambers. A small prototype module of such a calorimeter, has been tested using electrons of 5 to 100 GeV/c momentum with various high voltages and two gases: CO2 (100%) and CF4/CO2 (80/20), at atmospheric pressure. The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte-Carlo predictions. Agreement between data and simulation allows to make an estimation of the expected performance of a full size calorimeter
The CMS muon system
No full textDuring the first phase of operation of the LHC, with luminosities of the order of L=10/sup 33/ cm/sup -2/ s/sup -1/, a large production of bb pairs will allow the measurement of CP violation effects and other studies in B-physics. Identification and measurement of muons play an important role in these studies. This will be achieved in CMS with several technologies: in the barrel part, drift tube chambers (DT) can be used, whereas in the endcaps, cathode strip chambers (CSC) are better suited. A third type of detector, resistive plate chambers (RPC) will also be present in both, barrel and endcaps, providing a redundant and complementary trigger. A description of the three detectors, their main features and performance is presented. (12 refs)
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