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|  DOE-HDBK-1108-2002
Radiological Training for Accelerator Facilities
Instructor's Guide
Lesson Plan
Notes
D.
Van de Graaff Generator
One of the first machines to produce laboratory- accelerated particles
was the Van de Graaff generator.
1.
Operation
The Van de Graaff consists of a polished metal sphere and a
moveable belt. The function of the belt is to carry an electrical
charge up to the sphere where it is stored. This process can be
continued until a very high potential is developed in the
sphere.
2.
Early generators
In 1929, Van de Graaff built a pilot machine capable of
generating 80,000 volts. In 1931, a 1.5 million-volt (MeV)
machine was built at Princeton.
3.
State of the Art
A 25 MeV machine was built and operated at Daresbury
Laboratory in the United Kingdom.
E.
Cockcroft-Walton Accelerator
In 1932 in England, John D. Cockcroft and Ernest T.S. Walton
constructed what is called a linear accelerator using a high-voltage
source to accelerate protons through 700,000 volts (700 keV).
F.
Linear Accelerators
Straight-line
accelerators suffer
From the first simple machines (Cockcroft-Walton and Van de Graaff
from the
machines) evolved the larger and more elaborate machines. The
disadvantage that
modern example of this type of accelerator is the linear accelerator, a
the finite length of
sophisticated machine used in many scientific and medical
flight path limits
applications.
the particle
energies that can
G.
Lawrence and the Development of the Cyclotron
be achieved.
The great breakthrough in accelerator technology came in 1930 with
Ernest O. Lawrence's invention of the cyclotron.
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