The change in the 15-ev characteristic energy loss suffered by 15-kev electrons passing through a thin film of aluminum has been measured as a function of temperature from 4.2°K to 518°K. It is found that above room temperature the energy loss change agrees, within experimental error, with the change expected due to decreased electron density resulting from expansion of the lattice. However, below room temperature the energy loss change is much greater than expected on the above basis. It was also found that the half-widths of both the energy loss and the zero loss lines increased with decreasing temperature while the ratio of these two remained constant.

• Received 18 June 1958

DOI:https://doi.org/10.1103/PhysRev.112.341