Miniaturized Low Frequency Electric Field Sensing for Underwater Applications

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Microelectronics;Quantum Science OBJECTIVE: Develop a novel, low SWaP (space, weight, and power) electric field sensor for installation in maritime environments. DESCRIPTION: The Navy utilizes electric field sensing to monitor emissions from corrosion protection systems. Electric field measurements in maritime environments are traditionally acquired using pairs of sensitive electrodes separated by a relatively large baseline. State of the art sensing systems that have a direct current (DC) response employ silver chloride electrodes, but these electrodes are susceptible to drift while deployed in maritime environments. An example of current specifications for silver chloride electrode drift and accuracy can be found in the impressed current cathodic protection system military specification: MIL-DTL-23919. The Navy desires a sensitive, low SWaP electric field sensor with a DC response that is stable while deployed in the ocean. The desired sensor will be expected to: - Fit into dimensions of: 10 centimeters by 7.5 centimeters by 5 centimeters - Consume less than 10W of power continuously The objective is to develop a compact electric field sensor package, fitting into the dimensions listed above, that meets the following sensing requirements: - High dynamic range: 0.001 to 10000 millivolts per meter - High accuracy: 0.001 millivolts per meter - Low frequency: DC through 500 Hz - Low noise: 0.001 mV/m/rtHz at 1 Hz (Threshold), 10 nV/m/rtHz at 1 Hz (Objective) - Resist biofouling and operate in conductivities from 0.1 to 10 S/m - Biaxial or triaxial design - Orthogonality shall be established to within 1 degree - Accuracy and dynamic range requirements shall be met for each independent electric field component axis It is essential that the sensors maintain these accuracies under environmental stresses in the ocean. These conditions include: temperature 0-50 C, hydrostatic pressure up to 10,000 kPa, total suspended solids of 0-120 mg/L, fouling and biofouling over extended deployment periods. Advanced technologies for accurate measurement of local electric fields are sought and may include quantum sensing technologies. Technologies can be revolutionary and physical in nature, such as using phase transitions to sense electric fields. Recently, it was demonstrated that the insulator to metal (IMT) transition in perovskite nickelates could be used to sense marine electric fields [Ref 1]. Technologies can also be evolutionary in nature, such as using improved silver chloride chemistry to reduce the accuracy or drift errors resulting in more accurate small scale electric field measurements. Technologies based on existing silver chloride chemistry but using novel, alternate data processing means to achieve desired accuracy will be considered as well. PHASE I: Develop a concept for compact electric field sensing meeting the accuracy requirements outlined in the Description. Demonstrate the feasibly of the concept to meet the parameters listed in the Description through modeling, simulation, and analysis. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II. PHASE II: Develop and deliver two prototypes of the proposed electric field sensor sensors. Demonstrate the prototype's performance under the necessary environmental stresses. Deliver two such packaged sensors for Navy evaluation. The Navy will evaluate the prototypes for all requirements outlined in the Description section in a relevant seawater environment. PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology through system integration and qualification testing. Implement cost reduction measures and install sensor at various locations. Demonstrate operation of the sensor package for a minimum of two years through the collection of background electric field data to support long term environmental data collections. Show that the system is able to collect data for magneto telluric surveys. REFERENCES: 1. Zheng, Z, et al. Perovskite nickelates as electric-field sensors in salt water. Nature, Vol. 553, Jan 2018, p. 68. https://www.nature.com/articles/nature25008 2. Reference Cell, Impressed Current Cathodic Protection (ICCP) Silver-Silver Chloride. MIL-DTL-23919D(SH), 14 April 2020. 3. Constable, S. Review Paper: Instrumentation for marine magneto telluric and controlled source electromagnetic sounding. Geophysical Prospecting, 61 (Suppl. 1), 2013, pp. 505-532. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.2012.01117.x 4. Jau, Y.Y. and Carter, T. Vapor-Cell-Based Atomic Electrometry for Detection Frequencies below 1 kHz. Phys. Rev. Appl., 13, 5, May 2020, Article 054034. https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.13.054034 KEYWORDS: Underwater Electromagnetic; Compact Ocean Sensing; Electric Field Measurement; Underwater Electromagnetic Measurement Range; Low SWaP; Quantum Sensing