The Cathode Laboratory is well-equipped with a state-of-the-art cathode diagnostic system.  Ultrahigh vacuum is acheived, allowing detailed measurements of quantum efficiency for interesting surface coatings, laser wavelengths, and operating temperatures.  A unique dispenser photocathode concept is the hallmark of our current research.

 

The UMD dispenser photocathode is a cylindrical cell of stainless steel holding a cesium source inside.  The photoemissive end face is porous sintered tungsten.  Under gentle heating, the cesium diffuses out to the tungsten surface, lowering the workfunction in a replenishable fashion and increasing quantum efficiency.  The goal of current research is to acheive a high efficiency, long-lived photocathode by fabrication techniques that support commercial application, and to conduct investigations in support of groundbreaking photoemission theory.