120047073
A MRPC prototype for SOLID-TOF in JLab
A prototype of Multi-gap Resistive Plate Chamber (MRPC) for the future SoLID time of flight system at JLab has been developed. The counter, trapezoidal in shape, is assembled with the newly developed low-resistive Chinese glass. It has 10 × 0.25 mm gas gaps and 11 readout strips of different lengths. The strip width is 2.5 cm with a strip-to-strip interval of 3 mm. Preliminary tests performed with cosmic-rays showed an efficiency higher than 95% and a time resolution around 50 ps. Results under diffuse/uniform irradiation performed at JLab with scattered high energy electrons showed a time resolution of 70–80 ps and over-95% efficiency up to an incoming flux of 15 kHz/cm2. These performances meet the requirements of the new time of flight system SoLID-TOF.
125833326
Measurement of the decay K(L) ---> pi0 gamma gamma
123820860
Measurement of wake-field suppression in a detuned X-band accelerator structure.
Research is under way at SLAC to develop accelerator structure for a next generation linear collider. A full-scale prototype {ital X}-band structure has been built in which the dipole mode frequencies were detuned to suppress the long-range transverse wake field by about 2 orders of magnitude. To verify that the detuning works as expected, a facility, the Accelerator Structure Setup, was constructed in the SLAC Linear Collider to measure the long-range wake field. This Letter presents the results from the measurement of the prototype {ital X}-band structure with this facility.
209835030
Alignment of the CMS Silicon Tracker during Commissioning with Cosmic Rays
This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOP
56361182
STATUS OF THE X-BAND RF POWER SOURCE DEVELOPMENT FOR JLC
In this paper, we summarize the status of X-band RF power source development for the Japan Linear Collider (JLC) project. The periodic permanent magnet (PPM) klystrons are under development in the two-year/two-stage project with Toshiba. The goal is to produce 50MW output power at 1.5 µs pulse length at the first klystron and then to advance to 75MW at the second one. The high power testing of the first klystron is scheduled to start in July 2000. The multi-mode RF windows have been high power tested at KEK and SLAC. The window with smaller diameter (53mm) achieved a circulation power of 80MW with 1.5µs duration at 30Hz repetition. It was not destroyed during the testing. As for the modulator, the SIthyristor solid state switches were tested successfully. KEK is developing the multi-mode 2x2 DLDS (Delay Line Distribution System) power distribution system, in which the stability of linearly polarized TE12 mode in a long (up to 160m) waveguide is the key for low loss power transport. The experiment was carried out successfully in the ATF linac tunnel in collaboration with SLAC using a specially installed 55m long waveguide. Details of these developments and measurement results are presented.
122603752
CMS Data Processing Workflows during an Extended Cosmic Ray Run
The CMS Collaboration conducted a month-long data taking exercise, the Cosmic Run At Four Tesla, during October-November 2008, with the goal of commissioning the experiment for extended operation. With all installed detector systems participating, CMS recorded 270 million cosmic ray events with the solenoid at a magnetic field strength of 3.8 T. This paper describes the data flow from the detector through the various online and offline computing systems, as well as the workflows used for recording the data, for aligning and calibrating the detector, and for analysis of the data.
8650274
Probing anomalous top quark couplings at e gamma colliders
We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in single top quark production at a high-energy e gamma collider. We analyze all possible dimension-six CP-conserving operators which can give rise to an anomalous Wtb coupling which represents new physics effects generated at a higher-energy scale. For those operators which also give rise to anomalous Zb(b)over-bar or right-handed Wtb couplings, we find that they are strongly constrained by the existing R-b and b --> s gamma data. As a result, a collider with a luminosity of the order of 100 fb(-1) is required to observe anomalous effects. For other operators which currently are: subject to no strong constraints, the high-energy e gamma collider can probe their couplings effectively because of the clean environment of such a collider. [S0556-2821(98)01719-6]
23658132
First look at the beam test results of the FPIX2 readout chip for the BTeV silicon pixel detector
High energy and nuclear physics experiments need tracking devices with increasing spatial precision and readout speed in the face of ever-higher track densities and increased radiation environments. The new generation of hybrid pixel detectors (arrays of silicon diodes bump bonded to arrays of front-end electronic cells) is the technology able to meet these challenges. We report the first results of the BTeV silicon pixel detector beam test carried out at Fermilab in summer 2004. Tests were performed using a 120 GeV/c proton beam incident on a 6 plane pixel detector telescope. The last prototype developed for the BTeV experiment (FPIX2) is tested in the middle of the telescope. There is no external trigger, and events were built using the time-stamp information provided by the readout chips
38883802
Measurement of branching fractions for B-->eta(c)K(*) decays.
We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB.
207917728
AN FPGA-BASED TUNE MEASUREMENT SYSTEM FOR THE APS BOOSTER SYNCHROTRON
The Advanced Photon Source (APS) injection booster is a 7-GeV electron synchrotron with a ramping time of 226 ms and a repetition rate of 2 Hz. A real-time tune measurement system is needed in order to monitor and correct tune drift during the 226-ms energy ramp. Such a drift occurs during user beam operations, especially during continuous top-up operations, and results in shotto-shot efficiency fluctuations. We designed and developed an FPGA-based system that pings the beam at variable intervals and measures tunes. An operational system has been built and commissioned. It has achieved a time resolution of better than 2 ms and a tune resolution of better than 0.001. This report describes the system design and main parameters, and results from our preliminary commissioning. We also briefly discuss the application of such a system in ramping correction and ring diagnostics.
14412863
First Results From The Taiwanese-American Occultation Survey (TAOS)
Results from the first 2 years of data from the Taiwanese-American Occultation Survey (TAOS) are presented. Stars have been monitored photometrically at 4 or 5 Hz to search for occultations by small (~3 km) Kuiper Belt objects (KBOs). No statistically significant events were found, allowing us to present an upper bound to the size distribution of KBOs with diameters 0.5 km < D < 28 km.