Applications of MeV proton and deuteron linear accelerators

There are a number of applications, either proposed, currently under development or already reduced to practice, that utilize proton or deuteron beams in the 1-10 MeV energy regime. These applications have been reviewed and the accelerator requirements summarized. In terms of the beam time-structure, nearly all of the applications fall into three broad categories. (1) Beams that utilize nanosecond pulses at low duty factors (<0.5%) are required for a variety of material composition interrogation concepts using neutron time-of-flight techniques. (2) Pulsed beams, in the microsecond regime, are also used for material characterization utilizing (non-time-of-flight) characteristic nuclear signatures, where a low duty factor is used to suppress backgrounds. (3) High duty factor and continuous beams are needed for several applications, including neutron radiography (NR) and boron neutron capture therapy (BNCT), in which a high total current is required, or for which the time structure of the beam is unimportant. Linear accelerators of various types can meet most of the requirements for each category, but the high average power machines of the last category of applications require further development. The primary results of this review are presented, and an assessment of the current development status of radiofrequency accelerators to meet the high-duty-factor requirements is given.