V. Smakhtin

Update: A reanalysis of hadronic cross section measurements at CMD-2

The updated results of the precise measurements of the processes e+e-->rho->pi+pi-, e+e-->omega->pi+pi-pi0 and e+e-->phi->KLKS performed by the CMD-2 collaboration are presented. The update appeared necessary due an overestimate of the integrated luminosity in previous analyses.

High-statistics measurement of the pion form factor in the ρ-meson energy range with the CMD-2 detector

We present a measurement of the pion form factor based on e+e- annihilation data from the CMD-2 detector in the energy range 0.6<sqrt(s)<1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five times larger than that used in our previous measurement.

Measurement of the e + e - → π+π- cross section with the CMD-2 detector in the 370-520-MeV energy range

The cross section of the process e+e- ->pi+pi- has been measured at the CMD-2 detector in the 370-520 MeV center-of-mass (c.m.) energy range. A systematic uncertainty of the measurement is 0.7 %. Using all CMD-2 data on the pion form factor, the pion electromagnetic radius was calculated. The cross section of muon pair production was also determined.The results of the experiment on the measurement of the e+e− → π+π− cross section in a cm energy range of 370–520 MeV are presented. The systematic measurement error is equal to 0.7%. In the vector dominance model, the pion electromagnetic radius is calculated using all the CMD-2 data on the pion form factor. The cross section for the production of a muon pair is measured in the energy range of the experiment.

Measurement of the Pion Form Factor in the Range 1.04 1.38 GeV with the CMD-2 Detector

The cross section for the process e+e− → π+π− is measured in the c.m. energy range 1.04—1.38 GeV by analyzing 995 000 selected collinear events including 860000 e+e− events, 82000 μ+μ− events, and 33000 π+π− events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2–4.2 and 5–13%, respectively.

Superconducting rectifier fluxpump for magnet system of the CMD-2 detector

A superconducting rectifier fluxpump has been used for the dc power supply of the magnet system of the CMD-2 detector on the VEPP-2M collider at the Budker Institute of Nuclear Physics in Russia since 1989. The fluxpump provides a complete pumping cycle: charging the magnet system, stabilization of the magnetic field, and discharging. The fluxpump consists of an air-core current step-up superconducting transformer and two groups of thermally controlled superconducting switches arranged as a fullwave rectifier. Critical output current during the test was 5.4 kA. The accuracy of the field stabilization provided by the fluxpump is 2.5/spl middot/10/sup -5/. The fluxpump has exhibited reliable and safe operation during its entire history of use.

Superconducting magnet system of the CMD-2 detector

This paper describes the superconducting magnet system of the CMD-2 detector. The magnetic field is provided by the main and two compensating superconducting solenoids. The unique features of this system are the solenoids protection method utilizing a distributed resistance along the coil and the power supply being a fluxpump type. The main solenoid produces a field up to 1.2 T in a volume of /spl phi/ 0.71 m/spl times/0.9 m. Its radiation thickness and E/M ratio are 0.38 X/sub 0/ and 5 kJ/kg, respectively. NbTi/Cu superconducting cables without any insulation and an aluminum stabilizer were used for the design of solenoid coils. The superconducting cable was wound in a stainless-steel bobbin and soldered by a PbSn alloy. The cooling bath provides a temperature of 4.2 K in the system. The superconducting magnet system of the CMD-2 detector was manufactured and tested in 1989.

Position resolution and efficiency measurements with large scale Thin Gap Chambers for the super LHC

New developments in Thin Gap Chambers (TGC) detectors to provide fast trigger and high precision muon tracking under sLHC conditions are presented. The modified detectors are shown t o stand a high total irradiation dose equivalent to 6 Coulomb/cm of wire, without showing any deterioration in their performan ce. Two large (1.2× 0.8 m 2 ) prototypes containing four gaps, each gap providing pad, strips and wires readout, with a total thickn ess of 50 mm, have been constructed. Their local spatial resolution has been measured in a 100 GeV/c muon test beam at CERN. At perpendicular incidence angle, single gap position resolution better than 60µm has been obtained. For incidence angle of 20 o resolution of less than 100µm was achieved. TGC prototypes were also tested under a flux of 10 5 Hz/cm 2 of 5.5-6.5 MeV neutrons, showing a high effi ciency for cosmic muons detection.

Test Results of the Thin Superconducting Solenoid for the CMD-3 Detector

The superconducting solenoid is designed to provide 1.5 T magnetic field in the CMD-3 detector. Its dimensions are 0.7 m in diameter and 0.9 m in length. The superconducting coil is made of two layers of NbTi/Cu cable 0.87 mm in diameter. The solenoid is protected from quench by shunts, which are uniformly distributed along the coil. The total resistance of the shunts is about 40 . The superconducting coil has a minimal radiation thickness compared with other solenoids (0.085 ). The superconducting coil is indirectly cooled by liquid helium being in nucleate pool boiling state at 4.2 K. High purity aluminum strips were used to keep the solenoid at 4.2 K. The magnet system was tested for liquid helium efficiency. In May 2007, the solenoid, surrounded by a dummy iron yoke, was charged to its design current. The quench behavior of the solenoid is discussed.

Performance of a Full-Size Small-Strip Thin Gap Chamber Prototype for the ATLAS New Small Wheel Muon Upgrade

Author(s): Abusleme, A; Belanger-Champagne, C; Bellerive, A; Benhammou, Y; Botte, J; Cohen, H; Davies, M; Du, Y; Gauthier, L; Koffas, T; Kuleshov, S; Lefebvre, B; Li, C; Lupu, N; Mikenberg, G; Mori, D; Ochoa-Ricoux, JP; Codina, E Perez; Rettie, S; Robichaud-Veronneau, A; Rojas, R; Shoa, M; Smakhtin, V; Stelzer, B; Stelzer-Chilton, O; Toro, A; Torres, H; Ulloa, P; Vachon, B; Vasquez, G; Vdovin, A; Viel, S; Walker, P; Weber, S; Zhu, C | Abstract: The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the present design value by undergoing an extensive upgrade program over the coming decade. The most important upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs). The NSWs will be installed during the LHC long shutdown in 2018/19. Small-Strip Thin Gap Chamber (sTGC) detectors are designed to provide fast trigger and high precision muon tracking under the high luminosity LHC conditions. To validate the design, a full-size prototype sTGC detector of approximately 1.2

Test of spatial resolution and trigger efficiency of a combined Thin Gap and fast Drift Tube Chambers for high-luminosity LHC upgrades

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