classic examples of basic research translated to significant, unforeseen development of commercial markets.2

This chapter describes types of electron accelerators and x-ray and neutron generation techniques, as well as detector technologies that might replace or reduce radionuclide sources in certain applications (see Chapter 1). The accelerators that might be used in these applications are summarized in Table 4-1. The applications and specific replacement technologies are described in greater detail in Chapters 5 through 9.

As illustrated in Table 4-1, there are a many choices of accelerator technologies and a range of possible configurations. The majority of the replacement technologies are based on electron accelerators, which can be configured to deliver either electron beams (e-beams) or x-rays. In many applications, x-rays can be advantageous because of their much greater penetration depths. However, because of the poor energy conversion efficiency in generating x-rays, the required beam powers for electron and x-ray beams differ by more than an order of magnitude for the same radiation dose rate.

It should be noted that there are many other industrial applications that have been made possible because of the properties of electron accelerators or where the clear advantages of the accelerators have already made them, rather than radionuclide radiation sources, the technology of choice. These include applications in material processing such as cross-linking of polymers or curing of composites where the high energy density in an accelerator beam is required (see, e.g., Masefield, 2004). Another application is cargo inspection where high energy density and high x-ray energy are desired to penetrate dense objects.

TABLE 4-1 Summary of Radionuclide Source Applications and Possible Accelerator Replacements

Application

Dose (Gy)

Accelerator Type

Radiation

Energy (MeV)

Power (kW)

Radiotherapy

Few

rf linac

E-beam or x-ray

≈2–30

≈1

Self-contained irradiators

≈1–25

X-ray tube

X ray

≈0.1– 0.4

≈1

Panoramic irradiators

≈100–25,000

dc linac; rf linac; Rhodotron

E-beam or x ray

≈5–10

≈10–1,000

Oil well logging

 

Electrostatic D-D or D-T

Neutrons

Accelerator produces ≈ 0.1 deuteron or triton for D-T, 2 deuteron for D-D; 2.45 or 14.1 neutron output

≈0.001

Radiography

<1

X-ray tube; Betatron; rf linac

X-ray

≈0.1–20

≈0.001–1

NOTES: Gy = the dose unit, gray; rf = radio frequency; dc = direct current; D-D = deuterium-deuterium fusion reaction; D-T = deuterium-tritium fusion reaction; MeV = mega-electron volt; kW = kilowatt.

SOURCE: Table provided by the committee.

2

For a general description of the commercial uses of industrial accelerators, see Berejka (1995).



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