Photoemission Measurements Of Photocathode Materials In The 115-400 A Range

With the intent of finding a sensitive photocathode material in the 130 Angstrom (100eV) X-ray range for use in a high resolution soft X-ray Conversion Microscope, photoelectron yields of several materials (mostly alkali halides,) were measured at the National Inst of Standards and Technology\u27s (NIST) Synchrotron Ultraviolet Radiation Facility II (SURF II). These measurements were made as a function of wavelength in the spectral range 115 Angstrom-400 Angstrom. The measured values are comparable to previous measurements of the photoelectron yields of these and similar materials, and to an existing model of photoemission (1-3). We also determined the effects of prolonged exposure to X-ray light on performance. Moreover, because of the hygroscopic nature of Alkali Iodides, measurements of the photoelectron yield versus wavelength were repeated for samples of CsI that were kept in storage for periods of time to determine the effects of storage time and water absorption on the photoelectron yield