
3.3 Small and Sealed-Tube Neutron Generators
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e compact accelerator is composed of the (1) ion source, (2) accelerating
region, and (3) target section. e ion source is often a low pressure gas, cold
cathode source (Penning trap) requiring crossed electric and magnetic elds to
contain the ions until they are accelerated from the cathode region. e sche-
matic of a generic neutron tube is illustrated in Figure 3.8. e target is usually
composed of a thin lm made of a metal such as titanium, scandium, or zirco-
nium, which is deposited on a copper or molybdenum substrate (Whittemore
1990). Titanium, scandium, and zirconium form stable chemic ...