Rapiscan Laboratories and Helicon Thin Film Systems have designed and developed a detector for the replacement of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> He-based detector modules. Our neutron detector consists of a thinly coated <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B flat-panel ionization chamber that can be deployed as a direct drop-in replacement for current RPM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> He detectors. The uniqueness of our approach in providing a large-area detector is the simplicity of construction, scalability of the unit cell detector, ease of adaptability to a variety of applications, and low cost. In the initial development, a smaller area, multi-layer prototype <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nat</sup> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> C-based ionization chamber was built and tested, demonstrating neutron detection capability and gamma-ray insensitivity. In the subsequent stage of detector development, enriched <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sub> C films were robustly deposited, passed temperature cycling testing, and were tested in the prototype chamber for neutron sensitivity. In addition to the development of the boron-coated substrates, a complete signal processing circuit, which includes a preamplifier, amplifier, and discriminator, was fabricated on a circuit board and tested within the prototype chamber. Currently, a portable detector has been tested.