Java·Applied·Geodesy·3D

Electron accelerator S-DALINAC

Laser tracker measurement at electron accelerator S-DALINAC Alinment of beam guidance elements at electron accelerator S-DALINAC
Laser tracker measurements (top) and alinment of beam guidance elements (bottom) at electron accelerator S-DALINAC

Electron accelerators are large physical facilities, which accelerate charged particles close to the speed of light. Such instruments are primarily used in fundamental research. Due to the hight accuracy requirements, usually laser trackers are used to align the elements of the beam guidance. The distance measurement unit of the laser tracker is the crucial component of the instrument. The specified uncertainties of a measured position is ≪0.1 mm. In contrast to classical geodetic instruments like a theodolite or a total station, the observations of a laser tracker are usually not related to the plumb line because the instrument is not levelled. For that reason, common geodetic adjustment tools fail to process laser tracker measurements.

The opensource adjustment package JAG3D allows for a rigorous network adjustment of laser tracker measurements based on the original observations. Moreover, measurements obtained by total stations or additional levelling loops can be rigorously combined with laser tracker data on the observation level. The software was successfully validated using data sets from the Deutsche Elektronen-Synchrotron (DESY, German Electron Synchrotron).

Laser tracker network adustment

Reference network of the electron accelerator S-DALINAC observed by laser trackers and rigorously adjusted by JAG3D
Reference network of the electron accelerator S-DALINAC observed by laser trackers and rigorously adjusted by JAG3D

The Superconducting-Darmstadt-Linear-Accelerator (S-DALINAC) is the thrice-recirculating electron accelerator operated by the institute for nuclear physics at Technische Universität Darmstadt.

JAG3D has been successfully used for years, to evaluate measurement concepts, to design network configurations, but primary to adjust the polar observations obtained by laser trackers. JAG3D processes several thousand raw observations, which were measured in a period from 2016 to 2021, in only a few seconds. The results are clearly arranged of the graphical user interface, which allows for an efficient evaluation of the network adjustment.