He invented the modern commercial ultrasonic nozzle, which in its application has brought many benefits to the fields of research, combustion and manufacturing.

During the 1960s he did work for General Electric while developing his doctoral thesis entitled "Effects of Recoilless Emission on Gamma-Gamma Angular Correlation in Sn-199" for which was awarded his PhD in Physics from RPI in June 1969.

While working at GE on various projects related to his doctoral thesis and the Mössbauer effect, Berger also did research on polymer chemistry and Cherenkov radiation.

Berger based his work on ultrasonic atomization first from the work of John William Strutt, 3rd Baron Rayleigh and his capillary waves in liquid as they relate to the frequency of vibration, imposed[1] and on that of Robert J. Lang whose published experiments involved atomizing melted wax and cooling and collecting the resultant small beads which he could measure.

U.S. patent 3,861,852 By the time Berger and his team had worked out a viable commercial design, the woes of oil crisis had passed and he set out to find the right applications for his new technology.