Non-invasive sensing of ultra-low, < 1 micro Amperes, electric currents is a critical technology for multiple physics, medical, and security applications. For example, by reading the magnetic field generated by a beam of charged particles, one can determine the beam position in space. This knowledge is critical for optimum operation of a high-energy accelerator facility, where the beam position is used for steering the beam towards a target location. Brookhaven Technology Group (BTG) and STAR Cryoelectronics (STAR) will design and develop a long-base high-temperature superconducting gradiometer instrument capable of detecting position of a particle beam as low as 1 nA. The technology relies on two key innovations. First, the sensing coil structure will be laser-machined from extra-wide (45 mm) second-generation superconducting tapes. Second, the sensing coils will be magnetically coupled to a high-performance quantum interference sensor, developed by STAR. The technology is expected to deliver high sensitivity, > 100 micron beam position error, and low cost of ownership. In this Phase I project, the team will numerically model the sensing coil structure in order to maximize the device sensitivity and suppress the effect of spurious magnetic fields. The optimized coil structure will be laser cut and assembled at BTG lab in Stony Brook, NY. The coils will be coupled to the quantum interference sensor, provided by STAR. The system sensitivity will be determined in the laboratory environment and finally at the beamline facility at Jefferson National Laboratory. In Phase II the team will deliver a full scale beam monitor capable of sensing the beam position in two dimensions. The instrument is a beam diagnostic tool that can be used at accelerator facilities, industrial ion beam processing, medical cancer therapy centers. The technology enables design of a practical long-base, > 2 ft, high-temperature superconducting gradiometer: an inexpensive device that can sense ultra-low magnetic fields generated by brain activity, hidden electric currents or magnetic objects. Such a device would be used for studies of brain pathologies, geological exploration, and industrial diagnostics. In summary, this development leverages prior federal investments in high-temperature superconductivity in order to create a new commercial value proposition. A low-cost device capable of detecting ultra-low magnetic fields is needed for research, industrial and security applications. The team will design a prototype of a magnetic field sensing instrument utilizing recently developed extra-wide flexible superconducting tapes and an advanced quantum interference chips.
