The CDFII Time-Of-Flight Detector and Impact on Beauty Flavor Tagging
The new CDFII detector incorporates a Time-of-Flight detector (TOF), em-ploying plastic scintillator bars and ﬁne-mesh photomultipliers. Since August 2001 the TOF system has been fully instrumented and integrated into the CDFII data acquisition system. With a design goal of 100 ps resolution the TOF system will pro-vide at least two standard deviations separation between K ± and π ± for momenta p < 1 . 6 GeV/c , complementing low momentum particle identiﬁcation by means of the speciﬁc ionization energy loss measured in the drift chamber. We describe the design of the TOF detector and discuss the current status of its calibration and initial performances. Finally we review the expected impact of the TOF detector in the ﬂavor tagging of neutral B S meson.
Design and performance tests of the CDF time-of-flight system
Abstract The CDF II detector contains a time-of-flight detector consisting of 216 scintillator bars of 279 cm length and 4×4 cm2 cross-section located at a radius of 138 cm from the beam axis. The bars are installed on the inner surface of the CDF solenoid, which produces an axial field of 1.4 T. Nineteen-stage fine-mesh photomultiplier tubes are attached at both ends of the scintillator bars. Photostatistics limit the time-of-flight resolution, which is expected to be 100 ps. The primary physics motivation is K± identification for improved neutral B meson flavor determination.
In-House Industrial Production of the Superconducting Conductor for the 43 T Hybrid Magnet of LNCMI-Grenoble
The hybrid magnet being built at LNCMI-Grenoble is based on the combination of resistive inserts, made up of Bitter and polyhelix coils, with a large bore superconducting outsert. It will produce, in the first step, an overall continuous magnetic field of 43 T in a 34 mm warm bore aperture. The superconducting coil will provide a nominal magnetic field of 8.5 T in a 1.1 m cold bore diameter. It relies on the novel development of an Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) cooled down to 1.8 K by a bath of superfluid helium pressurized at 1200 mbar. After a brief reminder of the specificity of hybrid magnets, namely the strong electromechanical coupling between resistive and superconducting coils, the main requirements of the RCOCC for efficient and reliable magnet operation are given. The test and validation phases prior to the industrial production of the RCOCC are reported, including the trial production of the ½ hard-drawn (H02 cold-worked) Cu-Ag 0.05% hollow stabilizer in continuous lengths of 325 m. The novelty of the RCOCC development concerns the assembly and the induction soft-soldering of the Rutherford cable on the Cu-Ag hollow stabilizer allowing a strict control of the interstrand contact resistance. Studies, developments, and the integration of the industrial production line at LNCMI-Grenoble are presented together with the result of the production of all RCOCC unit lengths.