High Precision Survey and Alignment of Large Linear Accelerators

For the future linear accelerator TESLA the demanded accuracy for the alignment of the components is 0.5 mm horizontal and 0.2 mm vertical, both on each 600 m section. Other accelerators require similar accuracies. These demands can not be fulfilled with open-air geodetic methods, mainly because of refraction. Therefore the RTRS (Rapid Tunnel Reference Surveyor), a measurement train performing overlapping multipoint alignment on a reference network is being developed. Two refraction-free realizations of this concept are being developed at the moment: the first one (GeLiS) measures the horizontal co-ordinates using stretched wires, combined with photogrammetric split-image sensors in a distance measurement configuration. In areas of the tunnel where the accelerator is following the earth curvature GeLiS measures the height using a new hydrostatic leveling system. The second concept (LiCAS) is based on laser straightness monitors (LSM) combined with frequency scanning interferometry (FSI) in an evacuated system. LiCAS measures both co-ordinates with respect to its LSM-beam and is thus suitable for geometrically straight tunnel sections. Both measurement systems will be placed on a train, which could do the reference survey autonomously

High precision survey and alignment of large linear accelerators

Future linear accelerators require new survey techniques to achieve the necessary alignment precision. For TESLA, the demanded accuracy for the alignment of the components is 0.5mm horizontal and 0.2mm vertical, both on each 600m section. Other proposed linear colliders require similar accuracies. These demands can not be fulfilled with common, open-air geodetic methods, mainly because of refraction in the tunnel. Therefore the RTRS (Rapid Tunnel Reference Surveyor), a 25m long measurement train performing overlapping multipoint alignment on a regular tunnel reference network is being developed. Two refraction-free realizations of this concept are being developed at the moment: GeLiS measures the horizontal co-ordinates using multipoint alignment with stretched wires as strightness reference. In areas of the tunnel where the accelerator is following the earth curvature GeLiS measures the vertical co-ordinate using a new hydrostatic levelling system (HLS). LiCAS is based on laser straightness monitors (LSM) combined with frequency scanning interferometry (FSI) in an evacuated system. LiCAS measures both coordinates with respect to its LSM-beam and thus is suitable for geometrically straight tunnel sections. Both measurement systems will be placed on a train, which could do the reference survey autonomous or semiautonomous

Characterizing the SpraySyn burners with MMC-LES

This paper presents a detailed validation of a modeling framework and its implementation for the simulation of flame spray pyrolysis (FSP) using different nozzle geometries of the so-called SpraySyn burner. Gas, liquid and particulate dynamics are compared against experimental data from literature as well as our own laser-Doppler anemometry, phase-Doppler anemometry and multi-line OH laser-induced fluorescence thermometry imaging measurements. The modeling framework consists of large eddy simulations (LES) coupled to the sparse-Lagrangian multiple mapping conditioning (MMC) model, a Lagrangian spray solver and a sectional description of the population balance equation. Simulations start downstream of the burner exit planes where turbulent inlet data for the gas and liquid phases are generated by independent LES that use a 1-Fluid method to capture the dynamics of the liquid jet break-up. The gas and liquid dynamics are validated and analyzed for an ethanol spray flame in the SpraySyn1 and SpraySyn2 burners. In these burners iron(III) oxide particulates are synthesized from iron pentacarbonyl (IPC)-ethanol solutions with varying IPC concentrations. The results demonstrate the very good predictive capabilities of the MMC modeling framework for the gas and liquid phases. The predictions of the particulate formation are validated by comparison of elastic light scattering (ELS) signals from experiments against synthetic ELS signals calculated from the simulations. Results are of reasonable accuracy for the SpraySyn1 FSP series but indicate an imbalance between particulate growth and dilution with the surrounding gas. Predictions for the SpraySyn2 FSP series are consistent with SpraySyn1 results and indicate an increased product particulate size due to an increased residence time downstream of the heat release zone

The LiCAS-RTRS - A survey system for the ILC

The ILC requires an unprecedented accuracy and speed for the survey and alignment of its components. The Rapid Tunnel Reference Surveyor (RTRS) is a self-propelled survey train, intended to automatically survey a reference network in the ILC tunnels with a design accuracy of 200 (500) microns vertical (horizontal) over each 600 m segment [1]. A prototype RTRS has been built by the LiCAS collaboration. It will shortly commence operation at DESY. The operation principle and expected performance of the RTRS will be explained. The status of the project as well as the principles and performance of the underlying measurement technique will be described

First data from the linear collider alignment and survey project (LiCAS)

The LiCAS project has developed a prototype robotic survey system for rapid and highly accurate surveying of long linear accelerator tunnel networks. It is aimed at the International Linear Collider (ILC). This Rapid Tunnel Reference Surveyor (RTRS) is an RandD instrument for evaluating the performance of the RTRS concept and its survey technology. The prototype has been commissioned in a test tunnel at DESY with initial calibrations and measurements ongoing. We will report recent results where they improve over previously reported work

First data from the linear collider alignment and survey project (LiCAS)

The LiCAS project has developed a prototype robotic survey system for rapid and highly accurate surveying of long linear accelerator tunnel networks. It is aimed at the International Linear Collider (ILC). This Rapid Tunnel Reference Surveyor (RTRS) is an RandD instrument for evaluating the performance of the RTRS concept and its survey technology. The prototype has been commissioned in a test tunnel at DESY with initial calibrations and measurements ongoing. We will report recent results where they improve over previously reported work