The next generation of light source aims at delivering electron beams with unprecedented brightness and emittance properties. A crucial requirement in these projects is the accuracy in the alignment and positioning control of the magnetic elements on the girder and the girders in the tunnel. While many beam based tools have been developed and successfully tested, the requirement in the mechanical engineering and alignment of such elements is still a major concern and a technology challenge. Different solutions are adopted by different light sources.
The scope of the dedicated topical mini-workshop is to review the best practices in in the design, construction and alignment of girders and their elements, including aspects related the assembly procedures and logistics.
The key topics to be addressed are:
- Review of requirements, alignment tolerances – from simulations and what is achieved.
- Is re-adjustment of magnets needed? Which magnets? How often? Why? What procedures are implemented?
- Experience already acquired at various facilities. Were target alignments met? Were target alignments checked? Is realignment done? Are girders moved? Are single elements moved? how often?
- Mechanical requirements on girders
(design topology, static deformations, vibration, adjustment needs and tools).
- Eigen-Frequencies, construction details to reach a high Eigen-Frequency. Limits of vibration amplitudes and first Eigen-Frequencies of the girder, of the magnets. Difference between theory and measurements.
- Fixation and support structure for magnets (and vacuum pipes?). Fixed magnets / movable magnets / remote moving. Procedure: key slots or pin/dowels, shimming and clamping or gluing or adjustable shims. Number of iterations and timeline aspects.
- Mechanical accuracy achieved with different methods, comparison with predictions
- Duration and personnel, Conditions (number of benches, climatized cabin, ...)
- Magnet alignment in tunnel, magnet repair vacuum chamber repair, girder swap.
Girder alignment in tunnel
- Alignment strategies and their practical implementation (laser tracker - survey networks - issues with settlements). Required accuracy/Achieved Accuracy
- Transport test experience, on public roads, on site, transport vehicles.
Magnet alignment on girders
- Procedure and set up and devices used (Stops, tools, survey, ...), Required accuracy/Achieved Accuracy
- referencing magnetic axes to survey targets on the outside of magnets during field measurements resp. during fiducialisation measurements
- Duration and personnel. Planned vs actual.
- Impact on assembly and cost (assembly procedures, cost review, etc.)