Abstract:
The production of x-rays has been a useful technique in many areas of
science, medicine and various industries for over 100 years. Over this
time various new methods of generating x-rays have been produced,
allowing improved performance in existing applications as well as
the application of x-rays in new areas. In this project a novel method
of electron beam production, with the potential for development
into a novel method of x-ray production is presented, using both
pyroelectric and ferroelectric materials.
The pyroelectric e ect, i.e. the generation of a charge due to a
change in temperature is an e ect exhibited by certain dielectric
materials. This e ect has previously been used in x-ray generation,
and has been su ently successful that a commercial device has been
produced: the Amptek Cool-X. While the Cool-X has only a limited
electron / x-ray energy, high energy applications of this technology
are present in the literature. This shows that these materials are
capable of high voltages. However, the technique is not suitable
for high beam intensity applications, limiting the potential use of
pyroelectric x-ray devices.
Ferroelectric electron emission is a technique used to generate elec-
tron beams by applying a high voltage pulse to a specially prepared
cathode. This technique has shown great potential for very high
intensity pulsed electron beam generation. The major drawback of
this technique is that while the cathodes are relitivly cheap and
easy to produce, the other required equipment (such as high vacuum
systems and high voltage pulse generators) is typically large and
expensive. This project combines these two technologies to create
an electron beam generation system that exhibits many of the ad-
vantages of each technology, while minimizing the drawbacks. The
result is a device using pyroelectric materials as voltage generatingelements for electron acceleration and high voltage pulse production,
while a ferroelectric cathode is employed as the electron generating
element. This system has been shown to, depending on con guation,
be capable of accelerating voltages above 5 kV, and generating total
collected charges of more than -40 nC per pulse.
