Systematic and precise investigation of beam dynamics in a high-intensity, electron linac for the injector of the B-meson experiment

对 B 介子实验注入器的高强度电子直线加速器中的束流动力学进行系统而精确的研究

• 批准号: 11640298
• 负责人: OGAWA Yujiro
• 金额: $ 2.3万
• 依托单位: High Energy Accelerator Research Organization
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640298/
• 关键词: B meson; Electron linear accelerator; Beam dynamics; KEKB; Linac

For systematic and precise investigation of beam dynamics in a high-intensity, electron linac for the injector of the B-meson experiment, the following research items have been carried out : (1) improvements of the alignment system, (2) beam-based alignment, (3) measurements of wake-field effects, (4) observation and optimization of bunch profiles, (5) tuning of isochronicity in the 180-degree arc section, (6) beam optimization by a downhill simplex method, (7) optics tuning based on the accomplishments of the above items. In the item (1), light-detection circuits were upgraded so that a data acquisition system by computers was constructed, while in the item (2), beam positions and field centers of magnets were adjusted within a precision of 0.1 mm by observing beam position monitor signals. Quadrupole-wake field effects were directly observed for the first time by measuring beam positions when initial offsets were given (item (3)). The results are in good agreement with a calculation based on the measurements of bunch profiles (4). In the item (5), the isochronicity in the arc section were examined by using a bunch-profile measurement system and accomplished by performing optics corrections, while in the item (6), the positron beam intensity was increased by applying a downhill simplex method to several parameters of the primary electron beam. With all above results, we could carry out the following tasks (item (7)) : (A) development of the software programs for realizing a real-time optics correction, (B) its application to the case for abnormal beam states : prompt beam diagnosis and cures, (C) precise investigation of the quadrupole-wake field effects. Especially in the task (C), it was clarified that the quadrupole-wake field effects show non-linearity as well as x-y coupling phenomena in the orbit. This is the first result obtained in the world.

为了系统和精确地研究B介子实验注入器用高强度电子直线加速器中的束流动力学，开展了以下研究项目：(1)对准系统的改进，(2)束流对准，(3)尾场效应的测量，(4)束团轮廓的观测和优化，(5)180度弧段等时线的调谐，(6)用下坡单纯形法进行束流优化，(7)在上述研究成果的基础上进行光学调谐。在第(1)项中，对光探测电路进行了升级，从而构建了计算机数据采集系统；在第(2)项中，通过观察束位置监测信号，将磁体的束位置和场中心调整到0.1 mm的精度。在给定初始偏移量的情况下，首次通过测量束流位置直接观察到四极尾迹场效应(第(3)项)。计算结果与基于束团分布测量的计算结果符合得很好(4)。在第(5)项中，用束团轮廓测量系统检查了弧段的等时性，并进行了光学校正，而在第(6)项中，正电子束强度是通过对初级电子束的几个参数应用下坡单纯形法来增加的。有了上述结果，我们可以进行以下工作(项目(7))：(A)实现实时光学校正的软件程序的开发；(B)它在异常束流状态情况下的应用：及时的束流诊断和治疗；(C)四极尾迹场效应的精确研究。特别是在任务(C)中，阐明了四极尾波场效应在轨道上表现出非线性和x-y耦合现象。这是世界上第一个取得的成果。

项目成果

T.Kamitani: "Beam switching and beam feedback systems at KEKB linac"Proc.of the 7th European Particle Accelerator Conference. 1507-1509 (2000)

T.Kamitani：“KEKB 直线加速器的光束切换和光束反馈系统”第七届欧洲粒子加速器会议的会议记录。

Y.Ogawa: "Performance of the upgraded injector linac for KEKB"Proc.of the International Workshop on Performance Improvement of Electron-Positron Collider Particle Factories (e+e-Factories'99). 64-69 (1999)

Y.Okawa：“KEKB 升级喷射器直线加速器的性能”正负电子对撞机粒子工厂性能改进国际研讨会（e-Factories99）的Proc.。

K.Furukawa: "TOWARDS RELIABLE ACCECERATION OF HIGH-ENERGY AND HIGH-INTENSITY ELECTRON BEAMS"Proc.of the XXth International Linac Conference. 630-632 (2000)

K.Furukawa：“走向高能高强度电子束的可靠加速”第 20 届国际直线加速器会议的议程。

K.Ogawa: "Quadrupole wake-field effects in the KEKB linac"Proc.of the 7th European Particle Accelerator Conference. 1161-1163 (2000)

小川：“KEKB 直线加速器中的四极尾流场效应”第七届欧洲粒子加速器会议的会议记录。

K.Oide: "Commissioning of the KEKB factory"Proc.of the 1999 Particle Accelerator Conference. 288-292 (1999)

K.Oide：1999 年粒子加速器会议的“KEKB 工厂调试”Proc.。