EuCARD -HFM and its context

1. EuCARD-HFM and its context Gijs de Rijk CERN

2. EuCARD: European Coordination for Accelerator Research & Development  EuCARDEuCARD is a common venture of 37 European Accelerator Laboratories, Institutes, Universities and Industrial Partners involved in accelerator sciences and technologies. The project, initiated by ESGARD, is an Integrating Activity co-funded by the European Commission under Framework Programme 7 for a duration of four years, starting April 1st, 2009. Its main goal is to upgrade the large European research accelerators by R&D on innovative concepts and techniques, thereby offering researchers the best facilities. This common venture will strengthen durable collaboration among the partners and will contribute to the development of world-class infrastructures, one of the main features of the European Research Area.

3. EuCARD activities

4. EuCARD WP7 High Field Magnets HFM: Superconducting High Field Magnets for higher luminosities and energies, 12 partner collaboration, CEA, CERN, CNRS-Grenoble, Columbus, BHTS, INFN-LASA, KIT, PWR, SOTON, STFC-D, TUT, UNIGE 5 R&D tasks: • Support studies, thermal studies and insulation radiation hardness • High field model: 13 T, 100 mm bore (Nb3Sn) • Very high field dipole insert (in HTS, up to ΔB=6 T) • High Tc superconducting link (powering links for the LHC • Short period helical superconducting undulator (ILC e+ source) Duration: April 2009 – April 2013 Budget 6.4 M€ total, 2.0 M€ EC contribution .

5. Task 3: High field model Jean-Michel Rifflet (CEA) CEA, CERN, PWR • Objective: Design, build and test a 1.5 m long, 100 mm aperture dipole with a design field of 13 T, using Nb3Sn high current Rutherford cables. The key component in a SC magnet is the conductor. In order to develop high field magnets it is essential to have a facility to tests the cables (not ‘just’ the strands) up to the maximum field. This magnet is intended to replace the present 10 T magnet in the Fresca cable test station at CERN. 5

6. EuCARD dipole “specification” The technologies to be used for Nb3Sn magnets, which are residing with the partners (e.g. high current density conductors, Nb3Sn wind-and-react coil fabrication, insulation) are to be brought together and tested in short models. Several of these technologies (superconducting cable, insulation, coil design, support structures) were partly developed during the FP6-CARE-NED project. The proposed dipole model will test these technologies for large accelerator magnets and the model will afterwards be used to upgrade the superconducting cable test facility FRESCA at CERN from 10 T to 13 T. The issues are to reach high fields in large apertures with good temperature margins in the coil, beyond the possibilities of Nb-Ti conductors. As a test bed for high field accelerator magnets a 1.5 m long dipole model will be build with an aperture of 100 mm and a design field of 13 T. For this dipole model, CEA-DSM and CERN will design together the magnet. CERN will do the conductor characterization. PWR will do the thermal design and thermal component tests. CEA-DSM will fabricate the coils and CERN will build the mechanical support structure. Combined teams will integrate the coils into the support structure. The cryogenic test of the model will be done in the CERN test station. • Deliverable:7.3.1 Dipole model test results analyzed R M48

7. Conductor R&D - NED and post-NED strands • The NED program achieved Nb3Sn 1.25 mm strands with JC of 1500 A/mm2 at 15 T and 4.2 K, filament diameter of 50 m, and RRR regularly in excess of 150 • The HFM program has since focussed on issues of cable production and degradation, and thermo-magnetic stability Bruker-EAS PIT, 288 subelements, (Nb-Ta)3Sn • An improved understanding of the thermo-magnetic stability has led to the decision to: • Reduce strand diameter (1 mm) • Limit strand critical current density (1250 A/mm2 at 15 T and 4.2 K) • Maintain a strict requirement on RRR and filament diameter Courtesy L. Bottura, B. Bordini

8. Task 4: Very high field dipole insert • Pascal Tixador (CNRS Grenoble-INPG ) CNRS, CEA, KIT, INFN, TUT, UNIGE,PWR • Objective: • Design and realization of a high temperature superconductor (HTS) very high field dipole insert (6-7 T), which can be installed inside the 13 T Nb3Sn dipole of task 3 • This is a very first attempt to approach 20 T in a dipole geometry. • (13 T + 6 T or 15 T + 6 T) • Very challenging • Issues: • Ic of the HTS conductor: need an averaged Jc of ~300A/mm2 • HTS coil fabrication • Forces ( ~1000 t/m) • Fixing into dipole • Coupling, quenching • First make small solenoids and only then a dipole 8

9. Task 2: Support studies (1) • RAL mix 71 ; DGEBA epoxy + D400 hardener • Epoxy TGPAP-DDS(2002) • LARP insulation;CTD101K + filler ceramic • Cyaniteester epoxy mix T2 (40% AroCy L10) MacejChorowski& JarekPolinski (PWR) PWR, CEA, CERN • Objectives: • Certify radiation resistance of radiation resistant coil insulation and impregnation • Make a heat deposition and heat removal model for the dipole Nb3Sn model with experimental validation and determine the thermal coil design parameters for the dipole modelmagnet. sub-tasks: • 7.2.1 Radiation studies for insulation and impregnation • 7.2.2 Thermal studies 9

10. Task 5: High Tc superconducting link AmaliaBallarino (CERN) CERN, COLUMBUS, BHTS, SOTON • Objectives: • Design of HTS bus: choice of HTS material definition of thermal conditions, requirements for stabilization and quench protection, modelling of quench propagation. • Design. realization and test of electrical joints and electrical terminations. • Mechanical design and assembly of a 20 m long superconducting link (26 pairs of 600 A). • Subtasks: • Studies on thermal, electrical and mechanical performance • Design and test of electrical contacts HTS-HTS and HTS-Cu • Design and assembly of a 20 m long HTS multi-conductor 600 A link 10

11. Task 6: Short period helical undulator (1) Short period undulator for the ILC positron source Jim Clarke (STFC-DL) STFC (DL and RAL) Period 11.5 mm , field >1 T Aim : • fabricate and test a short helical undulator prototype using Nb3Sn wire. • With: 11.5 mm period and winding bore of 6.35 mm. • Nb3Sn usage for high current density and large thermal margin to go higher than the 1.15 T achieved for Nb-Ti Primary challenges: • Nb3Sn insulation system (compatibility with heat treatment at 650C) • Thin insulation (high current density).