HIRFL-CSRE 脉冲堆积式高频数字低电平系统

为突破传统束流堆积方式瓶颈、提高重离子流强，兰州重离子加速器冷却储存实验环（HIRFL-CSRe）将采用移动式脉冲堆积方案（Moving Barrier Bucket）。该方案要求高频系统能产生高精度的单正弦电压，然而由于Barrier Bucket（BB）电压的宽带特性以及高频系统的非线性，高频腔内的BB电压存在着严重的失真问题。针对此问题，在全面分析了BB电压波形特性以及高频系统的频率响应的基础上，设计了BB电压预失真前馈控制方案，并详细描述了该方案的原理、仿真、软硬件设计以及实际测试结果。研究成果将应用于HIRFL-CSRe的BB束流堆积实验以及十二五强流重离子加速器（HIAF）的BB堆积模式。

Barrier bucket digital low level RF system in HIRFL-CSRe

To overcome the limitation of the traditional beam stacking method and accumulate the heavy ion beam to higher intensity, Heavy Ion Research Facility in Lanzhou (HIRFL) will adopt Moving Barrier Bucket (BB) stacking scheme in Cooling Storage Experimental Ring (CSRe). The amplitude, phase and periodic adjustable BB voltage produced by the Radio Frequency (RF) control system is the core of this accumulation mode. However, due to the wide-band characteristics of BB voltage and the nonlinearity of RF system, there will be serious distortion of BB voltage in RF cavity. Based on the analysis of the characteristics of BB voltage and RF system, the predistortion feedforward control is introduced to eliminate the distortion. This paper describes the mathematical model, simulation, hardware and software design and test results of this method in detail. The results will be helpful to the BB stacking experiment of HIRFL-CSRe and BB stacking mode of High Intensity heavy-ion Accelerator Facility (HIAF).