Lecture 3: Magnet production Magnet manufacturing - Indico
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Magnetic materials Manufacturing techniques QA & Acceptance tests Recurrent issues Magnetic measurements Cost estimates and optimization JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Lecture 3: Magnet production Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnet manufacturing Mechanical design Tests & measurements Procurement • Raw materials • Tooling Magnet assembly Yoke production Coil production 1 Massive or laminated yokes Historically, the primary choice was whether the magnet is operated in persistent mode or cycled (eddy currents) + no stamping, no stacking + less expensive for prototypes and small series ‐ time consuming machining, in particular for complicated pole shapes ‐ difficult to reach similar magnetic performance between magnets + steel sheets less expensive than massive blocks (cast ingot) + less expensive for larger series + steel properties can be easily tailored + uniform magnetic properties over large series ‐ expensive tooling JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnetic steel Today’s standard: cold rolled, non‐oriented electro‐steel sheets (EN 10106) Magnetic and mechanical properties can be adjusted by final annealing Reproducible steel quality even over large productions Magnetic properties (permeability, coercivity) within small tolerances Homogeneity and reproducibility among the magnets of a series can be enhanced by selection, sorting or shuffling – Material is usually cheaper, but laminated yokes are labour intensive and require more expensive tooling (fine blanking, stacking) – – – – Courtesy of ThyssenKrupp 2 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Profile of steel strips The rolling process produces a thickness variation perpendicular to the rolling direction: Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Courtesy of ThyssenKrupp Courtesy of ThyssenKrupp Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary NGO steel properties ISOVAC 1300‐100A: Hc = 65 A/m Data source: VOESTalpine Austria JUAS 2015 Archamps, 23.‐27. February 2015 ISOVAC 250‐35HP: Hc = 30 A/m Data source: VOESTalpine Austria Sheet thickness: 0.3 ≤ t ≤ 1.5 mm Specific weight: 7.60 ≤ δ ≤ 7.85 g/cm3 Electr. resistivity @20°C: 0.16 (low Si) ≤ ρ ≤ 0.61 μΩm (high Si) 3 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sheet insulation Surface coating: electrical insulation of several μm thickness one or both sides oxid layer, phosphate layer, organic or inorganic coating – – – Insulation designation IEC 60404-1-1 Insulation type Color1) Coating Coating thickness each side in µm Insulation resistance at room temperature to ASTM A717/A717M-95 Ωm²/Lamelle STABOLIT 10 EC-3 by prior arrangement only organic yellowgreen both sides max. 1.5 > 15 STABOLIT 20 EC-5-P inorganic with organic components greygreen both sides 0.5 – 1.5 >5 STABOLIT 30 EC-5-P inorganic with organic components light grey both sides 0.5 - 1.5 >5 STABOLIT 40 EC-6 organic pigmented grey one or both sides 3.0 - 5.0 4.0 - 7.0 6.0 - 9.0 > 90 STABOLIT 60 EC-5 inorganic with organic components pigmented grey both sides 0.3 - 1.0 1.0 - 2.0 2.0 - 3.5 >5 > 15 > 50 STABOLIT 70 organic bonding lacquer (active) colorless one or both sides 5.0 - 8.0 - Combined insulation organic bonding lacquer with one side heat treatment (passive) colorless both sides active 5.0 - 8.0 - passive max. 1.5 Source: ThyssenKrupp Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Other magnetic materials 1. High purity irons – – – – 2. Low‐Carbon Steels – – 3. Iron referred to as "high purity" when total concentration of impurities (mainly C, N, O, P, S ,Si and Al) does not exceed a few hundred ppm Otherwise Low Carbon Steel or Non‐alloyed Steel Very pure F: high electrical conductivity not suitable for AC applications For high permeability at B > 1.2 T it is advisable to anneal at max. 800 °C and cool slowly e.g. type 1010 Disadvantage: Magnetic ageing (increase of coercivity with time) Non‐grain oriented Silicon Steels (NGO) JUAS 2015 Archamps, 23.‐27. February 2015 Advantages: – Increase in permeability – Decrease in hysteresis loss – Eddy current loss decrease due to higher resistivity (Al and Mn added as well) – No ageing 4. 5. Grain‐oriented Silicon Steels Iron alloys a. b. 6. 7. 8. Iron‐Nickel Iron‐Cobalt alloys with high magnetic saturation Compressed powdered Iron and Iron alloys Ferrites Innovative materials and rare earths Reference: S. Sgobba: Physics & Measurements of Magnetic Materials, CAS 2009, Brugges 4 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Yoke manufacturing Stamping laminations Stacking laminations into yokes Gluing and/or welding Machining Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Assembly (preliminary) Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Lamination punching • • • Punching or fine blanking Fine blanking requires more expensive tooling Tolerances less than +/‐ 8 μm achievable (depending on thickness, material and layout) Material can be delivered in sheets or strips (coils) JUAS 2015 Archamps, 23.‐27. February 2015 • 5 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Alternatives to punching Accuracy Repeatability [mm] [mm] Water jet cutting > 0.13 >0.025 rough cutting edge, relatively slow Laser cutting >0.01 >0.005 cutting edge ‚burnt‘, relatively slow CNC machining 0.01‐0.001 0.01‐0.001 Wire‐cut EDM > 0.002 >0.001 Technique Drawbacks stacks only very slow, limited size Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Yoke stacking Tooling for: • stacking • baking • welding JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 ...or a combination of different techniques 6 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Bonding & insulation Special coatings have been developed for the adhesive bonding of laminations: • • • • provide electrical insulation and mechanical bonding based on epoxy resins available in B‐stage (partly cured) and C‐stage (fully cured) Referred to as STABOLIT 70 by ThyssenKrupp Courtesy of Rembrandtin Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Glueing vs. Welding Welding Glueing + mechanically more ridgig + no aging ‐ massive end plates/tension straps needed ‐ continous welding introduces stress and deformation ‐ sophisticated welding procedure / requires stacking fixture + no stress, no distortions + no tension straps, no end plates ( no eddy currents) ‐ glue sensitive to radiation and aging ‐ requires clean laminations and conditions ‐ requires baking oven / requires stacking fixture JUAS 2015 Archamps, 23.‐27. February 2015 Recommendation: combine gluing, welding & bolting 7 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Coil manufacturing Define conductor type and material Conductor insulation Winding Ground insulation Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Epoxy impregnation Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Conductor materials Al Cu (OF) Purity 99.7 % 99.95 % Resistivity @ 20°C 2.83 μΩ cm 1.72 μΩ cm Thermal resistivity coeff. 0.004 K‐1 0.004 K‐1 Specific weight 2.70 g/cm3 8.94 g/cm3 Thermal conductivity 2.37 W/cm K 3.91 W/cm K JUAS 2015 Archamps, 23.‐27. February 2015 Key‐stoning: risk of insulation damage & decrease of cooling duct cross‐section R 3 A A 3.6% A 8 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Coil insulation In a magnet coil, the electrical insulation ensures that current flows only along the conductors and not between individual conductors or between the conductors and other parts of the magnet Dielectric materials can be distinguished in three main classes: – – – inorganic materials: ceramics, glass, quartz, cements and minerals (e.g. mica) organic materials: thermoplastic (Rubber, PA (Nylon), PP, PS, PVC, PC, PTFE) or thermosetting: Polyethylene, PI, PEEK, Epoxy, phenolic, silicon, polyester resins composites: fully organic (aramidic fibres‐epoxy tapes) or mixed (epoxy‐mica tapes) The electrical insulation is stressed by several factors: – – – – – electric thermal mechanical chemical (including oxidation) radiation JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 A weak electrical insulation may produce: – – – – current leaks with local heating up to melting and possible fire progressive damage of the leakage path up to a short circuit unbalanced circulating currents ( magnetic field distortion) incorrect functioning of protections Montsinger’s rule / Arrhenius equation: L(T 10 K ) 0.5t (T ) A temperature rise of 10 K halves the expected live time of an insulation system Reference: D. Tommasini: Dielectric insulation and high‐voltage issues, CAS 2009, Brugges Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Radiation hardness Radiation hardness is an important criterion for insulation materials used for accelerator applications Source: CERN Yellow Report CERN 98‐01 Above 108 Gy special insulation techniques are required! 9 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Radiation hardness Source: CERN Yellow Report CERN 98‐01 Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Coil insulation Conductors with small cross‐section: straigthening cleaning conductor insulation winding ground insulation JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary 10 Coil insulation Conductors with large cross‐section: straigthening winding sand blasting cleaning conductor insulation ground insulation Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Coil impregnation heating and evacuating mold and coil (auto‐clave or vacuum mold) mixing resing heating and degassing resin injecting resin curing cycle cooling JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary 11 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnet assembly By hand.... Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Auxiliary components • • • • • Electrical connections Hydraulic connections Interlock sytem (temperature, pressure, water flow) Magnetic measurement devices (pick‐up coils, hall probes) Alignment tragets, adjustment tables and support jacks JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 ... or with the help of tooling 12 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Hydraulic circuits • Water cicuits are most critical items • 95% of all magnet failures due to water leaks: – – – – – – – – – Corrosion Errosion Poor brazing quality Poor welding quality Failure or aging of joints Inadequate materials Incorrect assembly Radiation damage Inadequate design • Leaks can be detected and repaired during magnet acceptance tests and commissioning... • ... but, many leaks occur only after years in operation • Often not monitored magnet damage (short cicuits, corrosion of iron yoke) and collateral damages on other equipment possible Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Interlock Sensors Thermo‐switch: JUAS 2015 Archamps, 23.‐27. February 2015 Flow‐switch: 13 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary QA & Acceptance tests QA is important at each production stage • • • Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 • • Constant monitoring of critical items from the raw material, to semi‐finished parts, to sub‐ components to the final product Sample testing (destructive or non‐destructive) to qualify materials, manufacturing techniques and processes Acceptance test can include electrical, hydraulic, mechanical, thermal, and magnetic measurements Tests/measurements can be systematically (entire series) or on specific/random samples Complete recording and documentation indispensible (back‐tracing in case of doubts or failures) Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: JUAS 2015 Archamps, 23.‐27. February 2015 • • • • • • • Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation 14 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 • • • • • • • Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: • • • • • • • JUAS 2015 Archamps, 23.‐27. February 2015 Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation 15 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 • • • • • • • Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: • • • • • • • JUAS 2015 Archamps, 23.‐27. February 2015 Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation 16 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Sample testing Typically the following samples are tested to validate material performance and production processes: Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 • • • • • • • Magnetic steel Laminations Bond strenght (laminations) Brazing Welding Bond strength (coil) Impregnation Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Mechanical measurements Yoke shape and dimensional accuracy is essential for magnetic field quality in iron‐dominated magnets Mechanical errors can significantly influence the magnetic performance We distinguish between: • • Systematic errors (lamination contour) , can be relativley easy determined and corrected Random errors (stacking, machining, assembly), difficult to predicted, in general known only after series production, can be partly minimized by imposing low mechanical tolerances (expensive), enlarged design margins (expensive), strict quality assurance and close follow‐up of production processes JUAS 2015 Archamps, 23.‐27. February 2015 Mechanical measurements are required after each manufacturing step: • • • • • Lamination punching Yoke pieces (half‐yoke, quadrants) manufacture Yoke assembly Reproducability: after disassembling and re‐assembling (dowel pins) Stability: no deformation due to handling, lifting, transport (lifting test) 17 Mechanical measurements Various optical and mechanical techniques with different accuracy, precision and resolution are available for mechanical measurements Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Insulation testing • Insulation tests are an integral part of the electrical testing in addition to the measurements of the electrical coil resistance and inductance • An electrical insulation shall be tested to ensure its ability to provide the required insulation levels for specified operation and faulty conditions and during a specified time tests shall reveal manufacturing deficiencies • In most cases, this means specifying test levels much beyond the real operational conditions • For acceptance testing we typically perform two types of tests: JUAS 2015 Archamps, 23.‐27. February 2015 – High voltage test of a conductor to ground – Capacitor discharge test for inter‐turn insulation 18 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Power and heating tests Power test are performed to verify: – – – – correct interlock functioning no accidental over‐heating correct cooling performance absence of poor electrical contacts JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 – absence of moving or loose parts (pulse test) Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Recurrent quality issues Despite a severe quality control by the manufacturer, we often find quality deficiencies during the acceptance tests and certification at CERN Amongst several other recurrent issues, the following are the most frequent and most serious: – – – – – – – – – Poor brazing quality Poor bonding stength Poor coil insulation/impregantion Insufficient rust protection Loose or moving parts Covers not respecting IP2X Insufficient cable cross‐section Obstructed cooling circuits Transport damages due to inadequate packaging 19 Recurrent quality issues Lack/excess of brazing filler Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Recurrent quality issues Lack of resin: bubbles, voids, fissures, cracks, poor penetration, poor wetting Excess of resin: volumes of pure resin JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary 20 Recurrent quality issues Poor lamination bonding stength Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Magnetic measurements • Magnetic measurements as final proof if design and manufacturing is correct are an essential part of the magnet qualification process • Magnetic measurements are complementary to computer simulation and beam based measurements • No single instrument or method can cover all requirements – Multiple instruments are complementary – Overlaps provide estimation of absolute uncertainty and error correction • Commercial availability is very limited requires R&D, time and experience – Precise mechanics, stable materials, heavy benches are the foundation of good instruments • Different strategies for error correction: random errors are reduced by repetition – systematic errors are reduced by cross‐checks and by the use of symmetries JUAS 2015 Archamps, 23.‐27. February 2015 – 21 Overview of measurement techniques Type1 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Range [T] SQUID V 10‐1410‐4 < 1 < 1 Highest sensitivity, needs cryogenics Fluxgate V 10‐710‐2 10‐2 DC103 102 3 10 Main application: geomagnetic fields V 10‐1210‐3 10‐6 DC102 104 30 100 M‐optical V >10‐4 10‐2 DC109 103 >100 >100 M‐induction V 10‐610‐3 10‐2 DC103 100 5 5 M‐resistance V 10‐910‐3 10‐2 DC109 101 < 1 < 1 GMR sensor vital for magnetic recording industry; non‐ linear M‐diode V 10‐5101 10‐1 DC104 101 < 1 < 1 High sensitivity = 10x Hall, non‐linear M‐transistor V 10‐6100 10‐1 DC104 101 < 1 < 1 Very high sensitivity = 100x Hall, non‐linear Hall effect V 10‐5102 10‐3 DC104 103 <1 <1 Higher low‐prec BWsimple, cheap, commercially available accuracy requires laborious calibration Fixed coil V >10‐12 10‐4 10‐2106 104 5500 1 mm 10 m Rotating coil V >10‐12 10‐4 DC101 104 8‐400 1 mm 2 m Translating wire V >10‐3 10‐4 DC 104 0.1 < 20 m Classical system Oscillating wire V >10‐3 10‐3 DC 104 0.1 < 20 m Ongoing R&D NMR S 10‐5102 10‐6 DC100 104 10 10 Low field range only with custom flowing/water method FMR/EPR S 10‐810‐1 10‐4 DC103 104 40 40 Experimental Optical pump S 10‐510‐4 10‐6 DC101 104 100 1 m Method Fiber optic u2 [‐] BW3 [Hz] Cost4 [€] Size5 [mm] Length6 [mm] 10‐5 DC100 103 Notes Magnetostrictive sample deformation detected by Mach‐Zender interferometer Faraday effect (rotation of polarization). Extreme BW, compatible with extremely high fields Used for low‐power compass devices in GPS, smartphones … Digital out, T‐insensitive Linear, sensitivity increases wth BW Best all‐round performer for accelerator magnets Based on Zeeman effect in Rb, Ce Best resolution: 10 pT (1) V=vector, S=scalar (2) u=typical uncertainty (3) bandwidth (4) system cost (5) transversal sensor size (6) sensor size along the beam direction Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Field range and uncertainty 1.E‐07 FMR NMR 1.E‐06 1.E‐05 1.E‐04 Stretched wires Fixed/rotating coils JUAS 2015 Archamps, 23.‐27. February 2015 1.E‐03 Hall sensor 1.E‐02 1.E‐01 1.E‐12 1.E‐11 1.E‐10 1.E‐09 1.E‐08 1.E‐07 1.E‐06 1.E‐05 1.E‐04 1.E‐03 1.E‐02 1.E‐01 1.E+00 1.E+01 1.E+02 22 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Hall based instruments Hall head 3D/3D hall probe mapper rotating hall probe polarity checker b3/b5 probe: based on rings of fixed Hall plates Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Fixed coils (Fluxmeter) • • • • • Trivial solution to measure AC fields over large areas Arrays of coils measure field quality in one go PCB technology for inexpensive, precise large series runs Absolute calibration requires adequately sized reference magnet often not possible Used for relative Bd measurements (tracking) JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 3D Teslameter based on 3 Hall probe sensors (typically 1% absolute uncertainty) 23 Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 Rotating coils Provide simultanously information about field strength, quality (harmonics), direction and center n=1, B10 n=1, A10 n=2, B20 Discrete sampling of flux → Fourier components → Field harmonics Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Stretched Wire JUAS 2015 Archamps, 23.‐27. February 2015 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary 24 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary NMR technology Metrological reference: NMR devices are used as calibration standard for uniform fields ( = 0.1 ppm, u=5 ppm) • Limitations: • • • lowest field level 430 G tracking is slow (Hz): maximum field variation tolerated for latching δB/B < 1 % /s (4.5 G/s @ 450 G) field gradients blur the signal: max. field gradient for latching B/B < 10 …100 ppm/mm demodulated RF output in “marker mode” Courtesy www.metrolab.com Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Steel sheets: 1.0 ‐ 1.5 € /kg Magnet Material: Fixed costs 5 to 15 k€/tooling Magnet type Number of magnets (incl. spares) Total mass/magnet Design Punching die Stacking tool Winding/molding tool Yoke Production specific tooling: Yoke mass/magnet Used steel (incl. blends)/magnet Yoke manufacturing costs Steel costs Coil Cost estimate Coil mass/magnet Coil manufacturing costs Cooper costs (incl. insulation) Total costs Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 10 T Total order mass Total fixed costs Total Material costs Total manufacturing costs Total magnet costs Contingency Total overall costs Copper conductor: 10 to 20 € /kg Yoke manufacturing: Dipoles: 6 to 10 € /kg (> 1000 kg) Quads/Sextupoles: 50 to 80 € /kg (> 200 kg) Small magnets: up to 300 € /kg Coil manufacturing: JUAS 2015 Archamps, 23.‐27. February 2015 Dipoles: 30 to 50 € /kg (> 200 kg) Quads/Sextupoles: 65 to 80 € /kg (> 30 kg) Small magnets: up to 300 € /kg Contingency: 10 to 20 % Dipole 18 8330 kg 14 12 15 30 7600 10000 8 1.5 kEuros kEuros kEuros kEuros kg kg Euros/kg Euros/kg 730 kg 50 Euros/kg 12 Euros/kg 150 71 428 1751 2250 20 2700 Tonnes kEuros kEuros kEuros kEuros % kEuros NOT included: magnetic design, supports, cables, water connections, alignment equipment, magnetic measurements, transport, installation Prices for 2011 25 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Cost optimization Focus on economic design! Design goal: Minimum total costs over projected magnet life time by optimization of capital (investment) costs against running costs (power consumption) Total costs include: capital costs of magnets estimated operation costs of these items JUAS 2015 Archamps, 23.‐27. February 2015 capital costs of cooling system capital costs of power converters capital costs of power distribution Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Cost optimization Normalized costs Investment vs running costs Magnet capital Power equipm. capital Total capital JUAS 2015 Archamps, 23.‐27. February 2015 Running Total 2 3 4 5 6 7 8 9 10 Current density j [A/mm2] 26 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Cost optimization Normalized costs Total cost (j, energy costs) Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 n euros/kWh 2n euros/kWh 2 3 4 5 6 7 8 9 10 Current density j [A/mm2] Magnetic materials – Manufacturing – QA – Magnetic measurements – Costs – Summary Summary • The manufacturing techniques shall be adapted to meet the specified requirements of the finial product in all respects • Tight QA is the key for success and important at each production stage • Sample testing to qualify materials, manufacturing techniques and processes • Acceptance tests to verify the correct performance of the final product JUAS 2015 Archamps, 23.‐27. February 2015 • The yoke shape and dimensional accuracy is essential for magnetic field quality in iron‐dominated magnets • Magnetic measurements are an essential part of the magnet qualification process and complementary to computer simulations and beam measurements • Cost optimization is an important design aspect, in particular in view of future energy costs 27 Normal‐conducting accelerator magnets © Thomas Zickler, CERN Thanks for your attention… Normal‐conducting accelerator magnets © Thomas Zickler, CERN JUAS 2015 Archamps, 23.‐27. February 2015 … and many thanks to all my colleagues who contributed to this lecture, in particular L.Bottura, M.Buzio, B.Langenbeck, N.Marks, S.Russenschuck, D.Schoerling, C.Siedler, S.Sgobba, D.Tommasini, A.Vorozhtsov Literature • • • • • • • • JUAS 2015 Archamps, 23.‐27. February 2015 • • Fifth General Accelerator Physics Course, CAS proceedings, University of Jyväskylä, Finland, September 1992, CERN Yellow Report 94‐01 International Conference on Magnet Technology, Conference proceedings Iron Dominated Electromagnets, J. T. Tanabe, World Scientific Publishing, 2005 Magnetic Field for Transporting Charged Beams, G. Parzen, BNL publication, 1976 Magnete, G. Schnell, Thiemig Verlag, 1973 (German) Field Computation for Accelerator Magnets: Analytical and Numerical Methods for Electromagnetic Design and Optimization, S. Russenschuck, Wiley‐VCH, 2010 CAS proceedings, Magnetic measurements and alignment, Montreux, Switzerland, March 1992, CERN Yellow Report 92‐05 CAS proceedings, Measurement and alignment of accelerator and detector magnets, Anacapri, Italy, April 1997, CERN Yellow Report 98‐05 Physik der Teilchenbeschleuniger und Synchrotronstrahlungsquellen, K. Wille, Teubner Verlag, 1996 CAS proceedings, Magnets, Bruges, Belgium, June 2009, CERN Yellow Report 2010‐004 28
