111355896
GROUND VIBRATION MEASUREMENT AT NSRRC SITE
For the future TPS project in the NSRRC, ground vibration would be important for this new machine. We have monitored the ground vibration under various experimental conditions at NSRRC site. Sensors were installed in different sites, on the ground and underground in different depth up to 40 meters. From the collected data, we compare the effect of day and night, traffic effect, and internal machine vibration. Specific vibration sources and their propagations are also discussed.
53052085
Operational performance of the Taiwan light source
The Taiwan light source (TLS) is a 1.5 GeV third generation light source at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. It has been routinely operated since its opening in 1993. Several major machine upgrade projects have been undertaken and successfully completed in last 5 years, including implementing of digital bunch-by-bunch feedbacks, superconducting accelerating RF cavity, top-up mode injection, etc. The light source now moves forward to its era of mature operation. It delivers more than 5000 hours user time in 2007 with an up-time of more than 98% and a mean time between failures better than 80 hours. Here, we review its annual operational performance with detailed statistics and discuss the possible improvement directions of machine performance.
102344975
Directed flow from global symmetry and initial state Fluctuations
Collective flow is studied in a 3+1D fluid dynamical model with globally symmetric, peripheral initial conditions, taking into account the shear flow. At $\sqrt {s_{NN} } $ = 2.76 TeV in semi-peripheral Pb+Pb collisions this leads to rotation, while at more peripheral collisions with high resolution and low numerical viscosity, the initial development of a Kelvin-Helmholz instability is observed. This effect provides a precision tool for studying the viscosity of Quark-Gluon Plasma.
54084279
New method to detect rotation in high-energy heavy-ion collisions
The earlier introduced Differential HBT method aiming for detecting rotation is used to analyze the fluid dynamical model results of ultra-relativistic heavy ion reactions where the initial state has substantial angular momentum. The rotation effect and Kelvin Helmholtz Instability, lead to space-time momentum correlations, which can be detected by the method.
14802369
Coupling correction study at NSRRC
Emittance coupling between vertical and horizontal planes at TLS has been investigated. Using a set of skew quadrupoles, the coupling can be corrected to an acceptable value. The coupling sources are studied and possible errors are reduced.
54044418
Viscous potential flow analysis of peripheral heavy ion collisions
The conditions for the development of a Kelvin-Helmholtz Instability (KHI) for the Quark-gluon Plasma (QGP) flow in a peripheral heavy-ion collision is investigated. The projectile and target side particles are separated by an energetically motivated hypothetical surface, characterized with a phenomenological surface tension. In such a view, a classical potential flow approximation is considered and the onset of the KHI is studied. The growth rate of the instability is computed as function of phenomenological parameters characteristic for the QGP fluid: viscosity, surface tension and flow layer thickness.
42202614
Status of the NSRL Storage Ring UHV System after Project-II
The NSRL project-II has been finished in December 2004. The UHV system of storage ring has undergone improvement and now provide long beam lifetime and stable operations, the average pressure of ring is better than 2×10-8 Pascal without beam and 1×10-7 Pascal with beam, The typical beam lifetime is 12 hours at 300 mA and 800 MeV without wiggler and 8 hours at 300 mA and 800 MeV with wiggler on. The improvements and status of NSRL storage ring are described in this paper.
121851251
The forward muon detector of L3
The forward-backward muon detector of the L3 experiment is presented. Intended to be used for LEP 200 physics, it consists of 96 self-calibrating drift chambers of a new design enclosing the magnet pole pieces of the L3 solenoid. The pole pieces are toroidally magnetized to form two independent analyzing spectrometers. A novel trigger is provided by resistive plate counters attached to the drift chambers. Details about the design, construction and performance of the whole system are given together with results obtained during the 1995 running at LEP.
120097073
Tune optimization of modern light sources
How to find suitable working points plays an important role in the optimization of the third-generation light sources. Different methods of frequency map analysis, super-periodic structural resonance analysis, and single resonance approach are applied to study the effects of various resonances on the beam dynamics for different working points, trying to find some general strategies of tune optimization. Several guidelines for tune choosing are given at the end of this paper.
119280386
Links Between Z Sources and Atoll Sources
It is known that the Z and atoll sources are two typical types of neutron-star sources in low mass X-ray binaries (LMXBs), which present very different Q-ν relations of lower kHz QPOs. We propose that the Z and atoll sources are two different phases in the evolutionary track of neutron star in LMXBs, instead of two types of distinct sources.
31953693
Development and Application of Bunch-By-Bunch Measurement System of HLS
This paper is intended to present the newly implemented wideband (100MHz) bunch oscillation measurement system, which is in nature a different method from the narrow-band (< 5MHz) facilities employed before. Basic formalism and implementation details of the system is introduced to illustrate the function of observing coupled bunch instabilities in time and frequency domain. The designed function includes detecting of transverse oscillation, synchrotron phase oscillation, as well as bunch filling pattern. Some diagnostics results of machine instabilities and application of this system are also discussed.