He designed, developed and supervised procurement or fabrication of numerous power systems and electronic controls for accelerators at the Brookhaven National Laboratory (1968-1993). These systems included a shunt regulator and other servo control systems for the Main magnet Power System and three different beam extraction pulse current supplies for the Accelerating Gradient Synchrotron, a proton accelerator. Mr. Bagley was responsible for the design, development and build of the 200 power supplies which powered the guide field magnets of the National Synchrotron Light Source, an electron storage ring. He designed and developed various systems for the building and testing of the superconducting magnets used in the Relativistic Heavy Ion Collider, a heavy ion storage ring. He also redesigned the controls of a 5KA, 50V magnet power supply to achieve a ripple output of 0.1 ppm (IEEE Trans. On Nuclear Sci., 6/83). Gregory Bagley designed and developed control systems of inertial navigation components for ship and space applications, including a battery powered inverter with an associated battery charger and server control circuitry of Pulsed Integrated Pendulum Accelerometer (PIPA) used on the Lunar Lander built by Sperry Gyroscope (1962-1968).