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.
In Photos: Laboratory
Dispenser photocathode
6.5 keV Ar ion gun - surface cleaning
Cathode cell (right),
Cesium cartridge insert
Diode lasers
Lasers on automated translation stage
Anode (annulus),
Cathode (center)
Anode, Cathode
side view
Cs, K, Na evaporation sources
Sb evaporation source
Sources & Laser Port, as seen from cathode
Porous Tungsten on
Electron Microscope