Superconducting MgB2 tubes for Passive Magnetic Field Shielding for the Electron Ion Collider
The Department of Energy Nuclear Physics Accelerator Technology group seeks, among other things, cost-effective materials and manufacturing techniques for various special magnets for the proposed future Electron-Ion Colliders (EIC), which will require a full-acceptance system that can provide detection of reaction products scattered at small angles with respect to the incident beams over a wide momentum range. Significant effort will be needed for the design, modeling and hardware development of these special magnets. The design of proposed future EIC calls for an interaction region comprised of high field quadrupole for the heavier proton beams and an almost field free path (desired magnetic field within a few mT) for the electron beams. Magnets in the interaction regions have great challenges due to tight space and beam-beam interactions. A passive magnetic shield would reduce the spatial requirements around the electron beam pipe, lower the current in the required high field quadrupole, and possibly increase the luminosity. A superconducting solution is very promising for magnetic shielding since non-superconducting materials have limited capability at very low temperatures due to the loss of permeability. While low temperature superconducting NbTi wire commonly used in active shielding windings in MRI and NMR systems could be a choice in the future EIC, passive shielding in superconductor tubes will be much more compact than powered shielding with superconducting wires. Whereas long tubes of high temperature superconductors are costly and extremely challenging to fabricate, such is not the case for magnesium diboride (MgB2), a superconductor with a critical temperature of 39 K. MgB2 is proposed as a shielding material not only because it provides the possibility to safely work at intermediate temperatures (20–30 K) or operate in the boil-off of liquid helium already present in accelerator magnet systems, it also has many other advantages: 1) Higher temperature margin would reduce the need for NbTi shielding; 2) Shielding is passive and therefore would not require a power supply; 3) Shield tubes can be manufactured by a pressureless sintering technique to produce large parts in various shapes, including cylinders that can be designed to trap or hold transverse fields in the detector (the perfect diamagnetism of MgB2 allows for the spontaneous generation of currents, maintaining an original internal field); 4) Low fabrication costs, particularly as compared to other HTS superconductors (BSCCO and ReBCO); 5) Radiation tolerant.
- Research Organization:
- Hyper Tech Research
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- SC0019632
- OSTI ID:
- 1616955
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- Final DOE NP Phase I report MgB2 tubes
- Country of Publication:
- United States
- Language:
- English
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