Hadron Accelerator improvement toward high intensity and hi8gh brightness beams

1. 利用KEK-PS和J-PARC参数进行了包括电子云效应在内的不稳定性分析。研究了J-PARC环的踢球参数。基于二粒子模型和J-PARC参数的反馈阻尼器正反不稳定性分析。KEK-12 GeV-PS主环在注入能量（500 MeV）下的实验(1)一监控一踢的反馈阻尼实验。利用模拟电路成功地抑制了正反不稳定性（模式0，生长速率~ 30ms）。(2)采用数字信号处理（现场可编程门阵列快速处理）和模拟信号处理进行比较。获得了相似的阻尼时间。(3)稳定性分析采用单粒子模型。(4)采用数字信号处理的双监视器单踢脚反馈阻尼实验，稳定了不稳定性。但由于射频放大器存在较大的剩余COD（闭合轨道畸变）信号，因此无法研究强阻尼效应。消除COD成分是下一个主题。(1)采用单粒子模型，得到了双监测器和单踢球稳定性的精确解。快速阻尼区的解与小阻尼区的近似解有很大的不同，只要选择合适的参数，可以实现一圈或两圈的阻尼。问题是(a)振荡幅度在初始振幅上增加了一段时间；(b)稳定区域受到限制。(2)采用单粒子模型，得到了双监测双踢球稳定性的数值解。在这种情况下，上述两个问题都得到了解决。用两粒子模型和多粒子模拟进行分析是下一个课题。

1. Instability analysis including the electron cloud effect was performed using the KEK-PS and J-PARC parameters.2. A kicker parameter was studied for the J-PARC ring.3. Stability analysis of the head-tail instabilities with feedback dampers, using two-particle model, and the J-PARC parameters.4. Experiments at the KEK-12 GeV-PS Main Ring at the injection energy (500 MeV)(1) Experiment of feedback damping with one monitor and one kicker.Succeeded in damping a head-tail instability ( mode 0, growth-rate ~30 ms) using an analog circuit.(2) A digital signal processing (fast processing with a Field Programmable Gate Array) and an analog signal processing were applied and compared. Similar damping times were achieved.(3) Stability was analyzed with one-particle model.(4) Experiment of feedback damping with two monitors and one kicker with a digital signal processingThe instability was stabilized. But strong damping effect could not be studied because the RF amplifier was saturated with a large remaining COD (closed orbit distortion) signal. Elimination of the COD component is the next subject.5. Analysis of two-monitor and two-kicker configuration(1) Exact solution was obtained for the stability with two monitors and one kicker, using one particle model. The solution for the fast damping regime is far different from the approximate solution for the small damping regime, and realizes one-or two-turn damping if appropriate parameters are chosen. Issues are (a) oscillation amplitude increases over the initial amplitude for a moment; (b) the stability region is restricted.(2) The numerical solution was obtained for the stability with two monitors and two kickers, using one particle model. Both above issues are resolved in this case. Analysis with the two-particle model and multi particle simulation is the next subject.