Task7: NUSTAR2 - Design and Prototype Construction of a Radiation-Resistant Magnet C. Mühle GSI Task leader: G. Moritz /GSI

High-radiation area Design parameters and layout of the Super-FRS Magnets in the high radiation area QuantityField/gradient Length Usable apert. Gap height/Pole radius Dipole 1 11° T 2.39m 380x140mm 170mm Quadrupole 1 Ap.rad.10cm T/m 1m Ø90mm 100mm Quadrupole 2 Ap.rad.20cm T/m 1m 380x200mm 200mm Sextupole T/m 2 0.6m 380x200mm 200mm

Participating institutes in task7 (NUSTAR2) OrganisationSub-Task GSI Coordination, Radiation Impact, Magnetic Field Calculation, DesignDrawings, Prototyping Philipps Universität MarburgMaterial Research Technische Universität Dresden Cryogenics Fachhochschule MainzSurveying & Alignment Babcock Noell Nuclear (industry) Coil winding

Multi-annual implementation plan for NUSTAR2

Exploration of radiation load on magnets behind the high-power production target 3 different aspects of energy deposition Quench limit (2-3mJ/g): close to limit Material life time (see table): mineral insulation required Cooling requirements (expected FAIR cryogenic power: 20 kW): economic operation not possible Decision Normal conducting magnets with mineral insulated cable (MIC) Average energy deposition on on the coil surface: /M ≈ 1 mJ/g Equivalent to 14 MGy/a (4000h/a operation ) Heat load on the cryogenic system for a 5 ton quadrupole magnet: ≈ 2.3 kW Projectile: 1500 MeV/u 238 U /s σ x = 1.0 mm σ y = 2.0 mm σ p /p = 0.5% Energy deposition distribution (calculated with PHITS) Target: Carbon 4 g/cm 2 Material properties:

Mineral insulated cable (MIC) Potential suppliers Hitachi, Japan Kirscable, Russia Tyco Thermal Controls, Canada Copper conductor with and w/o cooling channel Rated up to 3000 A (engineering current density 3-6 A/mm 2 ) Expected cable costs ≈150€/m

Magnets with MIC New technology for GSI -> investigation of feasibility for all magnets potentially to be build with MIC 11° dipole (3 units) Quadrupole with 10cm aperture radius (2 units) Quadrupole with 20cm aperture radius (1 units) Sextupole (2 units) Conceptual designs for all magnets were prepared (additional collaboration work with P.Vobly (BINP) is appreciated) Direct cooling vs. indirect cooling was investigated Indirect cooling is favorable Cooling circuit and electrical circuit are separated -> no copper corrosion in the high radiation field Engineering current density is higher Conductor end plugs easier to be made Separation of water and current terminals to one end of the magnet, each Parameters of cooling circuit are independently from electrical circuit Use of one conductor cross section for all magnets probable

Example: Quadrupole with 10cm aperture radius Indirectly cooled Cable 14x14mm Copper cross section 9x9mm Current 1100A 170kW Directly cooled Cable 19.8x19.8mm Copper cross section 14.5x14.5mm Cooling channel 7.3x7.3mm Current 1900A 240kW Sizes are comparable!

Example: Dipole Indirectly cooled Laminated magnet Pole shims for improved field quality Bent magnet under investigation Half yoke weight: 43 tons Electrical terminals Cooling terminals

Example: Sextupole Indirectly cooled Laminated magnet

Surveying and alignment system for high-radiation areas  Remote-controlled camera vehicle in tunnel or on working platform  Eccentric photogrammetric targets on magnets  Sequential photogrammetric survey of inaccessible areas during shutdown  Bundle adjustment of photogrammetric network  Determination of correction values for magnet positions  Automatic, remote-controlled adjustment of machine geometry

Surveying and alignment system for high-radiation areas Work packages  Development of basic concept (photogrammetric solution)  Evaluation of camera specs; geometric camera tests  Design of algorithms for image analysis  Simulations of potential camera configurations  Camera tests at radioactive environments  Evaluation of constraints for accelerator design  Evaluation of criteria for automatic remote adjustment  Concept for integration in accelerator operation Most of the work packages ( ) are still in process since planning of accelerator design is not finished yet