Hadron Accelerator improvement toward high intensity and hi8gh brightness beams

1.利用KEK-PS和J-PARC参数进行了包含电子云效应的不稳定性分析.研究了J-PARC环的冲击参数.采用双质点模型和J-PARC参数，对带反馈阻尼器的头-尾不稳定性进行了稳定性分析.在KEK-12 GeV-PS主环上进行的注入能量（500 MeV）的实验（1）用一个监视器和一个冲击器进行反馈阻尼实验，用模拟电路成功地阻尼了一个头尾不稳定性（模式0，增长率~30 ms）。(2)应用并比较了数字信号处理（使用现场可编程门阵列的快速处理）和模拟信号处理。实现了类似的阻尼时间。(3)用单粒子模型分析了稳定性。(4)采用数字信号处理的双监控单冲击器反馈阻尼实验稳定了失稳。但是，由于RF放大器被大的剩余COD（闭合轨道失真）信号饱和，因此不能研究强阻尼效应。消除COD成分是下一个课题。双监视器双冲击器构型的分析（1）采用单粒子模型，得到了双监视器单冲击器构型稳定性的精确解。快阻尼区的解与小阻尼区的近似解有很大的不同，如果选取适当的参数，可以实现单匝或双匝阻尼。问题是（a）振荡幅度在初始幅度上增加了一段时间;（B）稳定区域受到限制。(2)采用单粒子模型，得到了双监视器双冲击器稳定性的数值解。以上两个问题在本案中都得到了解决。二粒子模型和多粒子模拟的分析是下一个主题。

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.