NbTi accelerator dipoles are limited to magnetic fields (H) of about 10 T, due to an intrinsic upper critical field(Hc2) limitation of 14 T. To surpass this restriction, prototype Nb3Sn magnets are being developed which have reached 16 T. We show that Nb3Sn dipole technology is practically limited to 17 to 18 T due to insufficient high field pinning, and intrinsically to 20 to 22 T due to Hc2 limitations. Therefore, to obtain magnetic fields approaching 20 T and higher, a material is required with a higher Hc2 and sufficient high field pinning capacity. A realistic candidate for this purpose is Bi-2212, which is available in roundwires and sufficient lengths for the fabrication of coils based on Rutherford-type cables. We initiated a program to develop the required technology to construct accelerator magnets from 'windand-react' (W&R) Bi-2212 coils. We outline the complications that arise through the use of Bi-2212, describe the development paths to address these issues, and conclude with the design of W&R Bi-2212 sub-scale magnets.

NbTi accelerator dipoles are limited to magneticfields (H) of about 10 T, due to an intrinsic upper critical field (Hc2) limitation of 14 T. To surpass this restriction, prototype Nb3Sn magnets are being developed which have reached 16 T. We show that Nb3Sn dipole technology is practically limited to 17 to 18 T due to insufficient high field pinning, and intrinsically to 20 to 22 T due to Hc2 limitations. Therefore, to obtain magnetic fields approaching 20 T and higher, a material is required with a higher Hc2 and sufficient high field pinning capacity. A realistic candidate for this purpose is Bi-2212, which is available in roundwires and sufficient lengths for the fabrication of coils based on Rutherford-type cables. We initiated a program to develop the required technology to construct accelerator magnets from 'windand-react' (W&R) Bi-2212 coils. We outline the complications that arise through the use of Bi-2212, describe the development paths to address these issues, and conclude with the design of W&R Bi-2212 sub-scale magnets.

We report on the progress in our R&D program, targeted to develop the technology for the application of Bi2Sr2CaCu2Ox (Bi-2212) in accelerator magnets. The program uses subscale coils, wound from insulated cables, to study suitable materials, heat treatment homogeneity, stability, and effects ofmagnetic field and thermal and electro-magnetic loads. We have addressed material and reaction related issues and report onthe fabrication, heat treatment, and analysis of subscale Bi-2212 coils. Such coils can carry a current on the order of 5000 A and generate, in various support structures, magnetic fields from 2.6 to 9.9 T. Successful coils are therefore targeted towards a hybrid Nb3Sn-HTS magnet which will demonstrate the feasibility of Bi-2212 for accelerator magnets, and open a new magnetic field realm, beyond what is achievable with Nb3Sn.

The RF coupling coil (RFCC) module of MICE is where muons that have been cooled within the MICE absorber focus (AFC) modules are re-accelerated to their original longitudinal momentum. The RFCC module consists of four 201.25 MHz RF cavities in a 1.4 meter diameter vacuum vessel. The muons are kept within the RF cavities by the magnetic field generated by a superconducting coupling solenoid that goes around the RF cavities. The coupling solenoid will be cooled using a pair of 4 K pulse tube cooler that will generate 1.5 W of cooling at 4.2 K. The magnet will be powered using a 300 A two-quadrant power supply. This report describes the ICST engineering design of the coupling solenoid for MICE.