23
Advanced
Strained-Superlattice Photocathodes for Polarized Electron Sources--SVT
Associates, 7600 Executive Drive, Eden Prairie, MN
55344; 952-934-2100
Dr.
Aaron Moy, Principal Investigator, moy@svta.com
Ms.
Jane Marks, Business Official, marks@svta.com
DOE
Grant No. DE-FG02-01ER83332
Amount:
$99,695
Negative-electron-affinity
(NEA) photocathodes, which produce polarized electrons, are a vital component of
electron accelerators. For the next
Linear Collider (NLC), the polarized electron beam intensity must be at least 20
times greater than that produced by strained GaAs, used in the current
generation of photocathodes. Additionally,
the degree of electron polarization needs to be increased beyond the 75%
currently attainable, and intrinsic materials properties must be tailored to
improving the surface charge limit. This project will develop a new generation
of photocathodes capable of yielding intense, highly polarized electron beams
for use in advanced electron colliders. A
strained-superlattice, formed from altering layers of GaAs and GaAsP
approximately ten monolayers thick, will be utilized.
In Phase I project the GaAs/GaAsP superlattice structure will be
grown by molecular beam epitaxy (MBE). This
technique is capable of atomic layer precision and is superior to metal organic
chemical vapor deposition in use for growing strained GaAs.
The optimization of the superlattice will be performed by varying the
structural design and the growth conditions in a matrix of experiments.
Commercial
Applications And Other Benefits as
described by awardee: A highly efficient polarized electron source should find
use in experimental research at the Stanford Linear Accelerator Center and other
electron collider facilities. These
devices would also have applications in magnetic research and surface science.