Magnet alignment on a common girder: Development of a length artefact for measurement accuracy improvement

Leão, Rodrigo Junqueira; Baldo, Crhistian Raffaelo; Reis, M. L. C. C.; Trabanco, Jorge Luiz Alves; Rodrigues, Flávio Henrique Guimarães; Neuenschwander, Regis

doi:10.1016/j.precisioneng.2017.04.013

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…In recent studies on alignment uncertainties from the Brazilian Synchrotron Light Laboratory (LNLS) [32], CMM alignment measurements uncertainties of both contact and non-contact probe heads were performed using a calibrated artefact. The alignment target for the 1.8 m assemblies was quoted as a 40 µm error and not as uncertainty; no confidence interval was given.…”

Section: State Of the Artmentioning

confidence: 99%

“…However, the calculation or prediction of the full 'task-specific' uncertainty of each CMM was not shown. Details were missing of the specific CMM and probe head uncertainties for the different tools, thermal effects, targets form error, and others [32]. This might not be adequate when the tolerances studied are at the limit of the metrology performance.…”

Section: State Of the Artmentioning

confidence: 99%

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Application of probabilistic modelling for the uncertainty evaluation of alignment measurements of large accelerator magnets assemblies

Doytchinov

Tonnellier

Shore

et al. 2018

Meas. Sci. Technol.

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Micrometric assembly and alignment requirements for future particle accelerators, and especially large assemblies, create the need for accurate uncertainty budgeting of alignment measurements. Measurements and uncertainties have to be accurately stated and traceable, to international standards, for metre-long sized assemblies, in the range of tens of µm. Indeed, these hundreds of assemblies will be produced and measured by several suppliers around the world, and will have to be integrated into a single machine. As part of the PACMAN project at CERN, we proposed and studied a practical application of probabilistic modelling of task-specific alignment uncertainty by applying a simulation by constraints calibration method. Using this method, we calibrated our measurement model using available data from ISO standardised tests (10360 series) for the metrology equipment. We combined this model with reference measurements and analysis of the measured data to quantify the actual specific uncertainty of each alignment measurement procedure. Our methodology was successfully validated against a calibrated and traceable 3D artefact as part of an international inter-laboratory study. The validated models were used to study the expected alignment uncertainty and important sensitivity factors in measuring the shortest and longest of the compact linear collider study assemblies, 0.54 m and 2.1 m respectively. In both cases, the laboratory alignment uncertainty was within the targeted uncertainty budget of 12 µm (68% confidence level). It was found that the remaining uncertainty budget for any additional alignment error compensations, such as the thermal drift error due to variation in machine operation heat load conditions, must be within 8.9 µm and 9.8 µm (68% confidence level) respectively.

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Section: State Of the Artmentioning

confidence: 99%

Section: State Of the Artmentioning

confidence: 99%

Application of probabilistic modelling for the uncertainty evaluation of alignment measurements of large accelerator magnets assemblies

Doytchinov

Tonnellier

Shore

et al. 2018

Meas. Sci. Technol.

View full text Add to dashboard Cite

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“…In this sense, the deviations between magn etic and geometric centerlines of the magnets are assumed to be systematic or negligible. Other papers deal specifically with the magnetic axis measurement and magnet-to-magnet alignment [31,32]. Simulations of the complete alignment procedure show that an alignment envelope between girders of 0.080 mm can be attained, at a coverage probability of 95%, using laser trackers as main measuring tool.…”

Section: Subject Mattermentioning

confidence: 99%

mentioning

confidence: 99%

Engineering survey planning for the alignment of a particle accelerator: part II. Design of a reference network and measurement strategy

Leão

Baldo

Reis

et al. 2018

Meas. Sci. Technol.

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The building blocks of particle accelerators are magnets responsible for keeping beams of charged particles at a desired trajectory. Magnets are commonly grouped in support structures named girders, which are mounted on vertical and horizontal stages. The performance of this type of machine is highly dependent on the relative alignment between its main components. The length of particle accelerators ranges from small machines to large-scale national or international facilities, with typical lengths of hundreds of meters to a few kilometers. This relatively large volume together with micrometric positioning tolerances make the alignment activity a classical large-scale dimensional metrology problem. The alignment concept relies on networks of fixed monuments installed on the building structure to which all accelerator components are referred. In this work, the Sirius accelerator is taken as a case study, and an alignment network is optimized via computational methods in terms of geometry, densification, and surveying procedure. Laser trackers are employed to guide the installation and measure the girders’ positions, using the optimized network as a reference and applying the metric developed in part I of this paper. Simulations demonstrate the feasibility of aligning the 220 girders of the Sirius synchrotron to better than 0.080 mm, at a coverage probability of 95%.

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“…In the last decades, several methods have been developed to cope with the alignment of accelerator components [4,5]. Of high importance is the alignment of focusing elements, mainly quadrupole and solenoid magnets.…”

Section: Introductionmentioning

confidence: 99%

On-field monitoring of the magnetic axis misalignment in multi-coils solenoids

et al. 2018

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Magnet alignment on a common girder: Development of a length artefact for measurement accuracy improvement

Cited by 9 publications

References 11 publications

Application of probabilistic modelling for the uncertainty evaluation of alignment measurements of large accelerator magnets assemblies

Application of probabilistic modelling for the uncertainty evaluation of alignment measurements of large accelerator magnets assemblies

Engineering survey planning for the alignment of a particle accelerator: part II. Design of a reference network and measurement strategy

On-field monitoring of the magnetic axis misalignment in multi-coils solenoids

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