| 摘要 |
<p>A radio-frequency multipole linear accelerator (10) is made to vary its particle acceleration energy without varying the frequency of a radio-frequency power supplied to the accelerator (10) and therefore, without providing to the accelerator any means for varying the effective resonance frequency of the accelerator itself. For this purpose the voltage of the radio-frequency accleration fields developed in the accelerator is varied irrespective of the normal acceleration condition conventionally taken into consideration. To achieve the purpose the radio-frequency accelerator (10) is power-supplied by an amplification-variable radio-frequncy power amplifier (2) whose amplification is automatically controlled so as to keep the acceleration voltage in the accelerator constant by a controller (4). The controller (4) outputs a amplification control signal by comparing a small power picked up from the accelerator by a pick-up loop (5) with adesired acceleration voltage determined by a voltage setting apparatus (3). With the accelerator (10) operated at an acceleration voltage lower than the value complying with the normal acceleration condition, the particle acceleration energy shows a plurality of spectra, resulting in a change in the average acceleration energy. Further, with a magnet (6) provided at the outlet of the accelerator (10), a particle beam having a specific acceleration energy can be also taken out.</p> |
