24/11/2017 Performance of the room temperature Systems for Magnetic Measurements of the LHC Superconducting Magnets at CERN J. Garcia-Perez, J. Billan, M. Buzio, P. Galbraith, D. Giloteaux, V. Remondino 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Outline Introduction Systems Description 24/11/2017 Outline Introduction Systems Description Measurements and Analysis Overview Performance: Local and Integrated Dipole Field High-order Harmonics Field Angle Experience Gained Conclusions 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

People involved 24/11/2017 Search coils manufacture (LHC/AT-MTM) R. Beltron, L. Gaborit Mole manufacture (AT & EST/ME) O. Dunkel, D. Cote, R. Camus, B. Girod, N. Mermillod, G. Patti, F. Fischer Software (AB/CO) and data reduction and analysis (AT-MAS) A. Rijllart, H. Reymond, A. Raimondo, E. Todesco, C. Vollinger, P. Hagen Bench for the mole translation inside quadrupoles (CEA/ Saclay) F. Simon Operators who did many measurements at CERN and outside in the assembly firms 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

The DIMM mole Slip rings Incremental encoder Gravity sensor 24/11/2017 The DIMM mole Slip rings Incremental encoder Gravity sensor Rotating coils Pneumatic brake 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

The search coils set for DIMM and QIMM 24/11/2017 The search coils set for DIMM and QIMM Dipoles Coils are 14.2 mm wide 3 coils per mole 25 moles built MQ, MQM, MQY & correctors Coils are 8.4 mm wide 5 coils per mole 12 moles built MQW (resistive) Coils are 7.4 mm wide 5 coils per mole 1 mole built 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Mole translation devices 24/11/2017 Mole translation devices Extensions - Manual Used for MQM, MQW, MQY Single mole, external rotating unit Measuring a magnet takes about 6 hours Cable – Automatic Used for MB 2 moles in parallel. About 2 hours per magnet. 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

QIMM Global view 24/11/2017 Coils and mole VME crate (integrators, ADC, IO, MXI, CPU) Coils bucking QIMM measuring a Short Straight Section SUN workstation Pneumatic brake Power Supply 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Systems characteristics review 24/11/2017 Systems characteristics review Characteristic DIMM QIMM Rotating unit placement internal external Number of search coils 3 5 Number of moles built 22 (+3 short) 12 Number of moles per system 2 1 Number of systems built 8 Search coil length [mm] 750 Nominal current [A] 10 12.5 Number of positions measured [750 mm sep.] 20 Search coil surface [m2] 3.7 1.97 Longitudinal positioning motorized manual 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Measurement and analysis overview 24/11/2017 Measurement and analysis overview Measurement procedure: Longitudinal positioning (auxiliary shafts or motor with StegmanTM) Orientation of mole to gravity Three Rotating coil measurements clock-wise and 3 anti clock-wise with both positive and negative currents (10 A→B1=7 mT or 12.5 A →B2=3.8 mT) Discrete Fourier Transform analysis on integrated voltage sampled signals (360 DIMM or 256 for QIMM) Harmonics normalization with respect to main field and gravity direction Harmonics normalization to magnetic centre (10th harmonics for dipoles or 1st for quadrupoles) and main field direction 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Performance Result DIMM QIMM 24/11/2017 Performance DIMM & QIMM are very efficient detecting magnet imperfection during CC measurement Field quality analysis detects misalignments and short circuits Corrective actions end in decollaring and repair CM measurement confirms CC one but Field angle measurement validate the magnet Repeated measurements intended to confirm assembly errors. Faulty measurements below 3 % Result DIMM QIMM Number of Collared Coil measured 919 314 Number of measurements on Collared Coil 1057 325 Number of Cold Mass measured 850 239 Number of measurements on Cold Mass Number of magnets with problems found in CC 67 11 Number of magnets with problems found in CM 6 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Local and Integrated dipole field 24/11/2017 Local and Integrated dipole field Local field measurement is very sensitive to assembly errors. Precision better than 10-4 Integrated field → longitudinal positioning precision → StegmannTM encoder precision better than 0.5 mm (Laser Tracker calibration) Magnetic length adjustment by adding or removing iron yoke laminations 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Measuring at the factories: example of assembly error 24/11/2017 Measuring at the factories: example of assembly error Main Field relative module: 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

24/11/2017 High-order Harmonics Search coils surface matching and their stability keeps precision better than 0.1 units. 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

Detecting defects – an example 24/11/2017 Detecting defects – an example Harmonics along the collared coils 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

24/11/2017 Field Angle In dipoles controls the vertical bending component (Tolerance 1 mrad) Needs good inclinometer (50 μrad) and stability during measurement (apertures parallelism) To be expressed in the geometrical coordinate system (absolute value) 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

24/11/2017 Experience gained More than half of the production passed. Firm 3 finished already Collared Coils and very soon the Cold Mass. Feed-back from firms operators very useful to minimize and optimize CERN interventions every 4-5 months. Several maintenance actions are done by firm technicians following our instructions. Three special, shorter moles (125 mm long search coils) produced to have better spatial resolution to localize defects. One per firm. DELRINTM feet improve the operation of mole orientation to gravity by its smaller friction coefficient than the originally used metallic feet. Jig tool to measure angular orientation of the cold mass on the warm magnetic bench is very useful to correct for eventual angular change between geometric and magnetic measurements benches. Mole calibrations show very good stability of the search coils characteristics and its positioning. 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland

24/11/2017 Conclusions Systems show good capability to detect early many defects in the industrial assembly of the LHC dipoles and quadrupoles main magnets Money savings greater than whole investment in the warm magnetic measurements System robustness keeps the maintenance frequency low (4-5 months) Hardware commonly available on the market. Software developed using industrial control system standards. Good warm-cold measurements correlation allows a drastic reduction of magnetic measurements test at cold, giving money and time savings 28/09/2005 J. GARCIA PEREZ CERN – Geneva – CH Juan.Garcia.Perez@cern.ch 14th International Magnetic Measurement Workshop 26-29 September 2005, Geneva, Switzerland