Lester Halbert Germer was born on October 10, 1896 in Chicago, Illinois and lived most of his childhood in Canastota, New York. He graduated from Cornell University in 1917. After graduation he joined Bell Labs and then served in World War I as a fighter pilot, earning a citation from General Pershing. After the war he returned to Bell Labs and finished his Ph.D. at Columbia University in 1927.
At Bell Labs, Germer initially worked as an assistant to Clinton Davisson. In April of 1925 Davisson and Germer began working on an experiment studying the diffraction of electrons off of a nickel surface. At first their results were similar to results obtained four years earlier. Then suddenly the results changed. Looking for an explanation for the change they cut open the vacuum tube containing the nickel target. With the help of microscopist F. F. Lewis they observed that the crystalline surface of the nickel target had changed due to extreme heating. They believed that the change in their results was due to the change of the crystalline surface of the nickel target.
They performed a similar experiment in 1927, after Davisson had attended a conference where Louis-Victor DeBroglie's hypothesis about the wave nature of matter was presented. When electrons of known velocity were used to bombard the nickel surface at a 45 degree angle they observed that the diffraction of the electrons obeyed Bragg's Law, which relates the wavelength of diffracted x-rays with the lattice spacing of the target and the angle of diffraction. This was the first proof of DeBroglie's particle wave hypothesis. For this work Germer and Davisson were awarded the Elliot Cression Medal in 1931 (Davisson shared the 1937 Nobel Prize in Physics with George Thompson, who preformed a different experiment confirming DeBroglie's hypothesis four months later).
DeBroglie's hypothesis, that matter, like electromagnetic radiation, has a wave like nature is one of the more surprising revaluations that came with the development of quantum mechanics. In his doctoral thesis DeBroglie hypothesized that the wavelength of matter is dependant on its mass and velocity and that the wavelength is equal to Planck's constant divided by the momentum (p=mass*velocity) of the matter (wavelength=h/p).
After this experiment Germer continued working at Bell Labs, studying the use of this technique to determine the structure of surfaces, work that eventually led to the development of the electron microscope. In addition to his work at Bell Labs, Germer was also an avid rock climber. On October 3, 1971, one week before his 75th birthday, Germer died of a massive heart attack while he was rock climbing.
Lieter, Daryll J. and Lieter, Sharon; "A to Z of Physicists"; Infobase Publishing; 2003
MacRae, Alfred U.; "Lester H. Germer"; Physics Today(1972)25:93-97
Lester Germer Wikipedia Entry