The Bonn Electron Stretcher Accelerator ELSA: Past and future
The Bonn Electron Stretcher Accelerator ELSA: Past and future
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波恩电子担架加速器 ELSA：过去和未来
DOI：
10.1140/epja/i2006-09-015-4
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
W. Hillert
中科院分区：
文献类型：
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作者：
W. Hillert
摘要。1953年，决定在波恩建造一个500MeV的电子同步加速器。它于1958年投入使用，是欧洲第一个交替梯度同步加速器。在这个加速器上进行了五年的光电实验后，一个更大的2.5GeV电子同步加速器建成并于1967年投入运行。这两个同步加速器都用于粒子物理实验，直到1982年至1987年，第三个加速器——电子拉伸环ELSA被建造并安装在物理研究所下面的一个单独的环形隧道中。ELSA于1987年投入使用，使用脉冲2.5GeV同步加速器作为预加速器。ELSA既可以作为产生同步辐射的存储环，也可以作为后加速器和脉冲拉伸器。应用接近第三整数共振的慢速提取，能量高达3.5GeV和高占空因子的外部电子束被输送到强子物理实验中。利用实验装置PHOENICS， ELAN, sapir， GDH和Crystal Barrel进行了各种光电生产实验。在90年代后期，在加速器上构建并设置了一个脉冲极化电子的砷化镓源。对ELSA进行了升级，以加速极化电子，并采用快速跳调和谐波闭合轨道校正的方法补偿去极化共振。通过对GDH和规则的实验研究，在加速器上成功地进行了第一次需要极化光束和极化目标的实验。在不久的将来，担架环将进一步升级，以增加外部电子束的极化和电流。此外，还将研究利用超导谐振器将最大能量提高到5GeV的问题。
Abstract.In 1953, it was decided to build a 500MeV electron synchrotron in Bonn. It came into operation 1958, being the first alternating gradient synchrotron in Europe. After five years of performing photoproduction experiments at this accelerator, a larger 2.5GeV electron synchrotron was built and set into operation in 1967. Both synchrotrons were running for particle physics experiments, until from 1982 to 1987 a third accelerator, the electron stretcher ring ELSA, was constructed and set up in a separate ring tunnel below the physics institute. ELSA came into operation in 1987, using the pulsed 2.5GeV synchrotron as pre-accelerator. ELSA serves either as storage ring producing synchrotron radiation, or as post-accelerator and pulse stretcher. Applying a slow extraction close to a third integer resonance, external electron beams with energies up to 3.5GeV and high duty factors are delivered to hadron physics experiments. Various photo- and electroproduction experiments, utilising the experimental set-ups PHOENICS, ELAN, SAPHIR, GDH and Crystal Barrel have been carried out. During the late 90's, a pulsed GaAs source of polarised electrons was constructed and set up at the accelerator. ELSA was upgraded in order to accelerate polarised electrons, compensating for depolarising resonances by applying the methods of fast tune jumping and harmonic closed orbit correction. With the experimental investigation of the GDH sum rule, the first experiment requiring a polarised beam and a polarised target was successfully performed at the accelerator. In the near future, the stretcher ring will be further upgraded to increase polarisation and current of the external electron beams. In addition, the aspects of an increase of the maximum energy to 5GeV using superconducting resonators will be investigated.