62822934
Precise timing adjustment for the ATLAS level 1 endcap muon trigger system
The ATLAS level-1 endcap muon trigger system consists of about 4000 Thin Gap Chambers (TGC) with 320,000 input electronics channels in order to find level-1 trigger candidates for muons in both endcap regions. Three TGC stations are deployed with about 1m interval with 15m apart from the interaction point in z-direction on each endcap side and the radius of the station (disc form) is about 25m. Usually hit signals are not timely aligned because of different cable length and different time of muon flight. In order to supply reliable level-1 endcap trigger signals, we must adjust timing of hit signals for all the channels with the precision of±2.5ns. In the meantime we have to adjust also the bunch crossing phase used in the TGC system with one from LHC. We need, however, actual bunch crossing signals in order to accomplish this. In this paper we discuss strategies for timing alignment of individual channels with the timing adjustment facility embedded in the TGC electronics system and for the adjustment of the phase shift of the bunch crossing signals.
10281433
Evaluation of test structures for the novel n + -in-p pixel and strip sensors for very high radiation environments
Abstract Radiation-tolerant n + -in-p silicon sensors were developed for use in very high radiation environments. Novel n + -in-p silicon strip and pixel sensors and test structures were fabricated, tested and evaluated, in order to understand the designs implemented. The resistance between the n + implants (interstrip resistance), the electric potential of the p-stop, and the punch-through-protection (PTP) onset voltage were measured before and as a function of fluence after irradiation. The technology computer-aided design (TCAD) simulations were used to understand the radiation damage and fluence dependence of the structures. The decrease in the interstrip resistance is a consequence of increased leakage current. The decrease in the electric potential of the p-stop results from a build-up of positive charge in the silicon–silicon oxide interface. The decrease and subsequent increase in the PTP onset voltages results from the interface charge build-up and an increase in acceptor states.
125122742
J/psi production in Cu+Cu and Au+Au collisions at RHIC-PHENIX
174792146
Development of a time projection chamber using gas electron multipliers ( GEM – TPC )
We developed a prototype time projection chamber using gas electron multipliers (GEM–TPC) for high energy heavy ion collision experiments. To investigate its performance, we conducted a beam test with three kinds of gases (Ar(90%)–CH4(10%), Ar(70%)–C2H6(30%) and CF4). Detection efficiency of 99%, and spatial resolution of 79mm in the pad-row direction and 313mm in the drift direction were achieved. The test results show that the GEM–TPC meets the requirements for high energy heavy ion collision experiments. The configuration and performance of the GEM–TPC are described. r 2006 Elsevier B.V. All rights reserved. PACS: 29.40.Cs; 29.40.Gx; 25.75. q
16646090
Two-dimensional dynamical triangulation using the grand-canonical ensemble
Abstract The string susceptibility exponents of dynamically triangulated two dimensional surfaces with sphere and torus topology were calculated using the grand-canonical Monte Carlo method. We also simulated the model coupled to d-Ising spins (d=1,2,3,5).