Microwave linacs

FIGURE 3.14 Schematic of an indirect accelerator (microwave linac). (From Singh, A. and Silverman, J., Eds., Radiation Processing of Polymers, Hanser, Munich,1992. With permission). 

Schematic of a microwave linear accelerator or linac The three most common designs of industrial low-energy electron accelerators...

In TW linacs, the microwave power is injected in one end of the waveguide and propagates to the other end. At that point, any residual microwave power is dissipated... 

Improvements in time resolution in the stroboscopic method were achieved at the University of Tokyo by use of a twin linac system in which one aceelerator delivers the electron pulse to the sample and the other generates the Cerenkov light pulse used as the analyzing light [151]. Both linacs are driven by the same microwave source and delay between the electron pulse and the light pulse is achieved by phase shifters [151a]. The result is that the time interval between these two pulses is less than 3 ps. 

The electron accelerators can operate several ways. The acceleration requires a force provided by an electric field, which can be a continuous electrostatic potential (e.g.. Van de Graaff) or oscillation in time and space as produced by radio frequency, microwave or laser radiation (e.g.. Synchrotron, LINAC). Most of these methods use heated cathode to get the acceleration of electrons, usually from an electrostatically (about 10 keV) pre-accelerated source. These accelerators can provide from several hundred keV to several hundred MeV energy electrons (Synchrotron accelerators can produce electrons even with GeV energy). 

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