scholarly journals The Construction of the BESIII Experiment

2006 ◽  
Vol 21 (27) ◽  
pp. 5371-5380 ◽  
Author(s):  
Yi-Fang Wang

BESIII is a high precision, general purpose detector for the high luminosity e+e- collider, BEPCII, running at the tau-charm energy region. Its design and current status of construction is presented.

2013 ◽  
Vol 22 (01) ◽  
pp. 1341002 ◽  
Author(s):  
MASAKI ANDO ◽  
the DECIGO WORKING GROUP

DECIGO Pathfinder (DPF) is a small (~350 kg) satellite orbiting the Earth. DPF was originally proposed as the first milestone mission for a future space gravitational-wave (GW) antenna, DECi-hertz Interferometer Gravitational wave Observatory (DECIGO). In addition to the purpose of space demonstrations for DECIGO, DPF has scientific objectives: observation of GWs from black-hole mergers and monitor of Earth's gravity, as well as establishment of space technologies for high-precision measurements. In this paper, we review the conceptual design, scientific outcomes and the current status of DPF.


2019 ◽  
Vol 214 ◽  
pp. 02024
Author(s):  
Benedetto Gianluca Siddi

Faster alternatives to a detailed, GEANT4-based simulation are being pursued within the LHCb experiment. In this context the integration of the Delphes toolkit in the LHCb simulation framework is intended to provide a fully parameterized option. Delphes is a modular software designed for general-purpose experiments such as ATLAS and CMS to quickly propagate stable particles using a parametric approach and to provide reconstructed physical objects as output. It includes propagation inside a magnetic field and parameterized response for tracking and muon systems as well as calorimeters. Particle energies are computed by smearing the initial visible particles momentaaccording to detector resolution. The present contribution illustrates the current status of the Delphes toolkit in Gauss, the LHCb simulation framework. In this integration the particle transport performed by GEANT4 and subsequent mimicking of detector response and reconstruction has been replaced with a parametric response of the various detector elements. The implementation required sig-nificant changes to Delphes itself to constrain the particle transport inside the detector acceptance and to match the LHCb dipole magnetic field. The configuration of various parametrisations of resolution and efficiency is also a major aspect of the work to provide a fully functional simulation. The output of the resulting fast simulation is formatted in such a way that can be used in the LHCb physics analysis framework.


Author(s):  
Takehiro Kume ◽  
Gota Yamaguchi ◽  
Kentaro Hiraguri ◽  
Yusuke Matsuzawa ◽  
Yoichi Imamura ◽  
...  

2000 ◽  
Vol 197 ◽  
pp. 223-231
Author(s):  
Ray P. Norris

Masers have been well studied as indicators of star formation regions for over three decades. Their small size, high brightness, and narrow velocity width mean that we can measure their position and velocity with enormous accuracy, and so they stand out as high-precision signposts amidst the swirling gas that they sample. Nevertheless, in most cases the complexity of their kinematics has defied attempts to use them to unravel the processes of star formation. However, the last two or three years have seen a resurgence of interest in these masers because of exciting new evidence that, in some cases, they are tracing with high precision the kinematics of material in circumstellar disks around massive stars. The very existence of circumstellar disks around these massive stars is puzzling, and yet the maser results have now been confirmed by other data at radio and infrared wavelengths. In this paper I will review the current status of high-resolution maser observations, discuss some of the puzzles that are now confronting us, and speculate on where our current tentative steps may lead us.


1971 ◽  
Vol 49 (8) ◽  
pp. 1004-1017 ◽  
Author(s):  
J. Leon ◽  
N. H. Steiger-Shafrir

High precision range and straggling measurements of 96.5 keV224Ra α-disintegration recoil particles in various gaseous media are described. Special emphasis is placed on the development of a uniform and non-degrading recoil source in order to insure accurate range determination and to prevent broadening of the straggling results by the source. Excellent symmetry for the range distribution curves for all, even the heavy gases, was obtained. The performance of the measurements in gases, where successive collisions can be considered as uncorrelated, enabled a detailed comparison with theoretical treatments of the nuclear stopping mechanism, dominating in this energy region. The results obtained were compared with the Lindhard theory and show good agreement, especially for the medium mass gases.


Author(s):  
M.A. Basarab ◽  
B.S. Lunin ◽  
E.A. Chumankin

Wave solid-state gyroscopes (WSG) are among the most modern navigation devices. Based on the phenomenon of precession of elastic waves in thin-walled axisymmetric bodies, WSGs have a simple design, including 2-3 fixed parts, and have a number of advantages over other types of gyroscopes: great resource of work; small random error; resistance to severe operating conditions (overload, vibration, gamma radiation); relatively small overall dimensions, weight and power consumption; preservation of inertial information during short-term power outages. From the point of view of practical application and technologies used, three main groups of WSG can be distinguished. Wave solid-state gyroscopes of high precision. In such devices, high-quality (with a Q-factor of over 1·107) quartz resonators, contactless sensors and actuators, as well as complex electronic control systems are used. The field of application today, for various reasons, is limited to space technology, which requires, along with high precision, a long working life. Micromechanical devices of low accuracy for mass use (laptop computers, toys, industrial equipment, etc.) Integration of micromechanical WSGs with satellite systems makes it possible to create small-sized inexpensive navigation systems for widespread use. This market segment is developing very quickly, but production of such devices requires a very high the level of development of the microelectronic industry. An intermediate group consists of sensors of general use with metal resonators. Although these devices are larger than micromechanical devices, their production technology is much simpler. Metal resonators with a quality factor of (3 ... 5)∙104 can be manufactured using universal metal-cutting equipment; such devices have a simple design, do not require the creation of a high vacuum in their housing, and widespread radioelements can be used in control units. As a result, devices of this group, possessing insignificant power consumption and long working life, have a low cost price. On the other hand, the comparatively large dimensions of the resonator allow their precise tuning, which makes it possible to sharply increase the accuracy of the gyro instruments. From these points of view, a general-purpose WSG with a metal resonator is the most promising device that should replace the rotary-type electromechanical gyroscopes used today, and the production of which can be quickly mastered by the domestic industry. The development of such sensors requires solving a number of scientific and technical problems. Since all the main characteristics of such a device are determined by the properties of the resonator, special attention should be paid to its design and production technology. One of the most difficult and expensive operations in the WSG technology is the balancing of the resonator, carried out to eliminate the mass imbalance that arises during its manufacture due to inevitable deviations from the ideal axisymmetric shape (inhomogeneity of the wall thickness, displacement of the centers of the outer and inner surfaces, etc.). At a nonzero value of the 4th harmonics of the mass imbalance, a splitting of the natural frequency of the resonator occurs, leading to random errors in the WSG. A number of technologies are described in the literature to eliminate this mass defect [3-5]. The resonator balancing according to the first three forms of mass defect is much more difficult. Here, oscillations of the center of mass of the resonator occur during operation of the gyroscope and additional dissipation of the energy of oscillations of the resonator in the nodes of its attachment. This leads to a dependence of the Q-factor of the resonator on the orientation of the standing wave and, consequently, to a systematic error of the device. Thus, the aim of this work is to develop a technique and equipment for balancing metal resonators according to the first three forms of mass defect, suitable for use in the production of general-purpose WSGs.


Sign in / Sign up

Export Citation Format

Share Document