Tracker Station Research Articles

Mathematical model of laser tracker measur-ing system for multiple control of large constructions

Laser trackers are widely used to non-contact measure large-scale aerospace products. If it is impossible to inspect the entire product with a single laser tracker with a fixed position, multi-station inspection is used. This paper aims todescribes the multi-station control of large-sized products geometry with using a laser tracker as a measuring tool. A three-segment welded cylindrical shell with a diameter of 4100 mm, a height of 1560 mm and a thickness of 24 mm is considered as an object of control. The coordinates of laser tracker and enhanced referring system points are determined from the conditions of their full visibility and the minimum measurement error. A mathematical model of the measuring system for large shell multi-station control for determining the relationship between the coordinates of points measured from different stations of the laser tracker is constructed. The reference points coordinates and laser tracker station coordinates of the measuring system are established in order to minimize the number of mathematical model unknown variables. The calculation results of the of the selected measuring system maximum allowable error was carried out. The experimental studies were carried out to confirm the main mathematical model assumptions. 276 points on the outer surface of the large shell were measured with laser tracker. To determine the deviation of the surface from the theoretical contour, a digital model of the theoretical contour of the assembly was built in the Spatial Analyzer software. The measured control points were compared with the surface of the digital model. The results of the experimental studies confirmed the main mathematical model approaches and showed that the error of the measuring system corresponds to the required values.

The tracking detector of the FASER experiment

FASER is a new experiment designed to search for new light weakly-interacting long-lived particles (LLPs) and study high-energy neutrino interactions in the very forward region of the LHC collisions at CERN. The experimental apparatus is situated 480 m downstream of the ATLAS interaction-point aligned with the beam collision axis. The FASER detector includes four identical tracker stations constructed from silicon microstrip detectors. Three of the tracker stations form a tracking spectrometer, and enable FASER to detect the decay products of LLPs decaying inside the apparatus, whereas the fourth station is used for the neutrino analysis. The spectrometer has been installed in the LHC complex since March 2021, while the fourth station is not yet installed. FASER will start physics data taking when the LHC resumes operation in early 2022. This paper describes the design, construction and testing of the tracking spectrometer, including the associated components such as the mechanics, readout electronics, power supplies and cooling system.

О выборе местоположения станций лазерного трекера для установки технологического оборудования

A review article on the alignment of technological equipment located on a closed ring path (for example cyclic accelerators). Such geodesic works are very difficult, since the tolerance for alignment in the radial and altitude directions is 0,05 mm. The main survey instrument in such works is a laser tracker. The positions of the laser tracker stations were studied during equipment alignment, taking into account the effect of errors in the transverse directions. The values of the mean square errors for the distances and angles of the API trackers are used. Calculations are made for distances from 0,5 to 10 meters usual for production of precision measurements. The cases of installation of a laser tracker outside and inside the project radius are considered. The results of error calculations when changing the vertical angle of the laser tracker are also presented. The obtained results enable determining the 3D zones for the alignment process equipment, which will improve the efficiency of geodetic works.

Configuration optimization of laser tracker stations for position measurement in error identification of heavy-duty machine tools

Location configurations greatly affect the accuracy of sequential multilateration measurements using a laser tracker. This paper presents an approach that optimizes the locations of a laser tracker to improve the accuracy of position measurement in geometric error identification for heavy-duty machine tools. The approach is based on a physical model of the whole working space with the considered constraints determined by the structures of heavy-duty machine tools. The optimal location configuration of the laser tracker is searched by minimizing the average error magnification factor for all the measurement points on the machine tool movement trajectory. The Monte Carlo method is then used to evaluate the final measurement uncertainty of the sequential multilateration measurement under different configurations considering the influence of the repeatability error. The experimental validations are conducted on a coordinate measuring machine and a realistic floor-type milling machine with a 5 m × 2 m × 1 m working space. The experimental results show that position measurement of the optimized configuration has higher accuracy with an improvement of 57.5% compared with that of another feasible configuration analyzed in the uncertainty evaluation. The validity of the location optimization approach is further verified for identifying geometric error with high accuracy using an error identification experiment based on the nine-line method.

Configuration Optimization of Laser Tracker Stations for Large-scale Components in Non-uniform Temperature Field Using Monte-carlo Method

The laser trackers play an important role in fabrication and assembly of aircraft, spacecraft and other large-scale products, and optimization of laser tracker configuration station is one of the core issues. When laser trackers are used on the shop floor, environment factors, especially non-uniform temperature can induce considerable measurement uncertainty. Aiming to reduce measurement uncertainty of laser tracker, optimization of laser tracker configuration station for large-scale components in non-uniform temperature field using the Monte-Carlo method is proposed. Firstly, an improved mathematical model for measurement uncertainty of laser tracker is established. This mathematical model is more applicable to measurement uncertainty evaluation of laser tracker because it takes main measurement uncertainty sources (mechanism system and non-uniform temperature) into account. Secondly, the Monte-Carlo method is used to evaluate measurement uncertainties of laser tracker in different configuration stations. Based on the measurement mathematical model, a serial of simulation data can be generated to evaluate the uncertainty of measurement task. Through iterations, the optimal configuration station of laser tracker, in which measurement uncertainty is minimal, can be obtained. Finally, an example of measurement scenario about measuring the inspection jig of an aircraft door demonstrates that the proposed method is feasible and effective. The proposed approach to identify the optimal position of laser tracker is intuitionistic and efficient.

Compressed baryonic matter at FAIR: JINR participation

The scientific mission of the Compressed Baryonic Matter(CBM) experiment is the study of the nuclear matter properties at the high baryon densities in heavy ion collisions at the Facility of Antiproton and Ion Research (FAIR) in Darmstadt. We present the results on JINR participation in the CBM experiment. JINR teams are responsible on the design, the coordination of superconducting(SC) magnet manufacture, its testing and installation in CBM cave. Together with Silicon Tracker System it will provide the momentum resolution better 1[Formula: see text] for different configuration of CBM setup. The characteristics and technical aspects of the magnet are discussed. JINR plays also a significant role in the manufacture of two straw tracker station for the muon detection system. JINR team takes part in the development of new method for simulation, processing and analysis experimental data for different basic detectors of CBM.

The LHCb silicon tracker: running experience

The LHCb Silicon Tracker is part of the main tracking system of the LHCb detector at the LHC. It measures very precisely the particle trajectories comingfrom the interaction point in the region of high occupancies around the beamaxis. It covers the full acceptance angle in front of the dipole magnet in theTracker Turicensis station and the innermost part around the beam axis in thethree Inner Tracker stations downstream of the magnet. The Silicon Trackercovers a sensitive area of 12 m2 using silicon micro-strip sensors with verylong readout strips.We report on running experience for the experiment. Focussing on electronic and hardware issues we describe some of the lessons learned and pitfalls encountered after three years of successful operation.

AirGuardian – UAV Hardware and Software System for Small Size UAVs

AirGuardian is a complex of an Unmanned Aerial Vehicle and ground station UAV hardware and software systems which has been developed at Obuda University. The hardware and software of the autopilot (AERObot), the antenna tracker station and the ground control station were simultaneously created resulting in the optimal cooperation of the modules. The aim of the research on AERObot – the special autopilot – was to create a generic autopilot which is capable of controlling different designs, weights and structures of airframes without any complex mathematical model recalculation.

LHCb Silicon Tracker Performance Studies

LHCb is one of the experiments for the Large Hadron Collider at CERN and is dedicated to B-physics and CP-violation measurements. To exploit its physics potential good tracking performance with high efficiency in a high particle density environment close to the beam pipe is required. Silicon strip detectors with large read-out pitch and long strips will be used for the LHCb Inner Tracker behind the magnet and the Trigger Tracker station in front of the magnet. We report here about the design of the Silicon Tracker, test beam results and the electrical tests foreseen during production

The LHCb Silicon Tracker

LHCb is one of the experiments for the Large Hadron Collider at CERN, dedicated to B-physics and CP-violation measurements. To fully exploit the physics potential, a good tracking performance with high efficiency in a high particle density environment close to the beam pipe is required. Silicon strip detectors with large readout pitch and long strips will be used for the LHCb Inner Tracker after the magnet and the Trigger Tracker station in front of the magnet. The design of the Silicon Tracker in LHCb and corresponding test beam results are presented here.

The LHCb silicon tracker

LHCb is a dedicated B-physics and CP-violation experiment for the Large Hadron Collider at CERN. Efficient track reconstruction and excellent trigger performances are essential in order to exploit fully its physics potential. Silicon strip detectors providing fast signal generation, high resolution and fine granularity are used for this purpose in the large area Trigger Tracker station in front of the spectrometer magnet and the LHCb Inner Tracker covering the area close to the beam pipe behind the magnet. Long read-out strips of up to 38 cm are used together with fast signal shaping adapted to the 25 ns LHC bunch crossing. The design of these tracking stations, the silicon sensor strip geometries and the latest test results are presented here.

A scintillating fiber tracker with high time resolution for high-rate experiments

A fast and precise scintillating fiber (SciFi) tracker, using 0.5-mm-diameter fibers (Kuraray SCSF-78MJ) and position-sensitive photomultiplier tubes (Hamamatsu H6568), has been developed for the COMPASS (NA58) experiment at CERN. Tests of a 16-channel prototype showed an excellent stability in time resolution, in spatial resolution, as well as in detection efficiency under different beam flux of up to 1.4 /spl times/ 10/sup 8/ muons/spill. Four SciFi tracker stations have been constructed and all of them are presently under operation in the experiment with high performances as expected from the prototype.

Investigation Into a Multilateration Laser Tracking System for the National Metrology Institute of South Africa

A baseline study for the implementation of multilateration with a laser tracker for the Dimensional Laboratory of the NMISA (National Metrology Institute of South Africa) was completed. Software which requires one laser tracker to perform sequential multilateration was developed for the lab. Simulation studies are also done with this program for verification and configuration motivation purposes. Other aspects of the study involved developing a prototype laser tracker station and performing kinematic simulation analysis on gimbal type trackers. With practical experience gained, recommendations are made for future multilateration development in the Dimensional Laboratory.