October 2000 Newsletter - Naval Postgraduate School

RESEARCH CENTER
RAD-HARD SEMICONDUCTOR CHIPS, continued from page 15
Creation of a Center of Excellence at NPS
Because of the importance of rad-hard electronics to both the defense and
commercial sector the organization of a center of excellence at NPS has a unique
ability and advantages in this field: a) Several faculty who research radiation
effects in electronics, b) Unique radiation sources (NPS LINAC and Flash X-ray
facility), 3) Graduate students cleared at the secret and top secret level, 4) Close
proximity to Silicon
Valley to interact with
semiconductor
foundry and virtual fab software firms, and 5) Close interaction with
DoD personnel in R&D, acquisition, and operations that require
rad-hard ICs.
For several years, projects related to radiation effects have been
increasing at NPS and the idea of a center has been discussed.
Recently the NPS Linear Accelerator (LINAC) and the Flash X-ray
facility have been revitalized. These facilities are now available for
faculty to supplement research and for outside researchers needing
radiation sources.
The faculty at NPS has a broad range in studying radiation effects
in electronics; Associate Professor Sherif Michael, Department of
Electrical and Computer Engineering, has done considerable work in
studying solar cells and analog electronics, Associate Professor
Douglas Fouts, Department of Electrical and Computer Engineer-
Electronics Technician Don Snyder in the early
1970s maintaining the LINAC beamline. Thirty years
later, Don Snyder was critical in revitalizing the ing, in the design and layout of rad-hard digital VLSI circuits, and
LINAC after damage due to flooding in 1998. --continued on page 17
HISTORY OF NPS’ LINEAR ACCELERATOR: THE “LINAC”
In the early 1960s, Franz Bumiller joined the NPS faculty
after several years of research at the Stanford High Energy
Physics Laboratory. He wanted to build a linear accelerator
at NPS that would be smaller than the Stanford accelerator.
Work was started in January 1965 and a beam was obtained
in 1967. NPS Physics Professors John Dyer and Fred
Buskirk were involved in this early phase of the NPS
LINAC.
The initial construction was funded by a $250,000 grant
from the Chief of Naval Research. Also much excess
equipment was obtained from Stanford laboratories.
Material obtained from Stanford included the accelerator
beam pipes, electromagnets to handle the beam and some of
the electronic instrumentation. In addition, much DoD
surplus was obtained, including about 100,000 pounds of
lead for radiation shielding.
In simple terms, a linear accelerator works by employing
microwaves to accelerate the electron beam. Faculty
The members of the new Center for
Radiation Hardened Effects and others
at NPS would like to thank both
Electronics Technician Don Synder,
Department of Physics, and Professor
Emeritus Fred Buskirk in providing
an exceptional effort to bring the
LINAC back to operation.
working at Stanford on microwaves for radar during WWII
had apparently visualized the possibility of accelerating
electron beams.
In any text on microwaves, it is noted that the TM o mode
of a circular wave guide has an electric field along the guide.
It is just this electric field which can be used to accelerate a
change. However, it is also noted that the phase velocity of
any waveguide mode is greater than c, the velocity of light.
But, Einstein’s relativity theory tells us that an electron must
have a velocity less than c.
To resolve this problem, the uniform waveguide (as used
in a radar set, for example) has loading discs installed.
These discs slow down the microwaves but require very high
frequency stability from the microwave source. The accelerating
process may be compared to a surfboard (electron)
riding in phase with an ocean wave (the microwave) and
staying at a point where it always gets a forward force.
--continued on page 17
NPS Research page 16
October 2000