Sterilization installation electron beam dynamics optimization
Some methods to increase efficiency of electron beam usage in sterilization installation, simulated by computer code “Beam Scanning”, are presented. These methods include a correction of the current waveform in deflecting magnet, forming slightly convergent electron flow and irradiation of lateral object sides by low-energy electrons in the energy spectrum.
Compact electron linacs for radiation technology systems
Compact, self-contained electron beam systems are used for sterilization of medical devices and materials, treatment of medical and infectious wastes, non-intrusive inspection of cargo containers, etc. These systems, having massive local radiation shielding, require compact accelerators. 5-MeV and 7-MeV electron linacs are presented in this paper. The accelerators use standing wave biperiodic structures fed by magnetron generators with 2.8 GHz frequency. The accelerators do not use an external magnetic field for the beam focusing. Bunching, acceleration and focusing of the beam are performed by an RF field of the accelerating structure.
New Low-Profile Applicators for Local Heating of Tissues
A new type of low-profile applicator is described giving efficient power transfer to tissue with low leakage. It consists of a resonant element spaced from a ground plane by low-loss material having high relative permittivity and some relative permeability. This combination is covered by similar material which can be placed in direct contact with the tissue to be heated, or separated from it by a water bolus as required. Laboratory measurements using phantom materials show that these applicators are well matched and produce well defined and relatively uniform heating profiles. Applicators having maximum dimensions of 3-15 cm covering the frequency range 1000-100 MHz, respectively, are described. Penetration depths of at least 4 cm at 100-200 MHz are achieved. Tests on anesthetised pigs and some clinical assessment have confirmed the usefulness of this compact low-frequency type of applicator and have shown that performance compares favorably with that of other recently reported types. The design can be optimized for treatment of specific sites, and suitable choice of dimensions and electrical characteristics of the layer material allow the low-profile concept to be extended over a wide range of operating frequencies.