标题： 超导TESLA腔 显示英文标题

标题： The Superconducting TESLA Cavities

摘要： 所提出线性电子-正电子对撞机TESLA的概念设计基于9腔1.3 GHz超导铌腔，其加速梯度在品质因数Q0 > 5E+9时达到Eacc >= 25 MV/m。TESLA测试设施（TTF）直线加速器的腔体设计目标设定为更为适中的值Eacc >= 15 MV/m。在首批27个工业生产的TTF腔中，测量得到在Q0 = 5E+9时的平均梯度为20.1 +- 6.2 MV/m，排除了几个月由于严重制造或材料缺陷而受影响的腔体。在第二批24个TTF腔的生产中引入了额外的质量控制措施，特别是涡流扫描以消除含有外来物质夹杂物的铌片，并对电子束焊接的执行提出了严格规定。这些腔体在Q0 = 5E+9时的平均梯度为25.0 +- 3.2 MV/m，仅有一个腔体因焊接缺陷而例外。因此，只需适度改进生产和准备技术即可满足具有足够安全余量的雄心勃勃的TESLA目标。本文详细描述了TESLA测试设施腔体及其相关组件的设计、制造和准备，并报告了腔体在测试低温恒温器和TTF直线加速器中的电子束中的性能。简要介绍了向更高梯度发展的持续研发工作。 显示英文摘要

摘要： The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate value of Eacc >= 15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q0 = 5E+9 was measured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities additional quality control measures were introduced, in particular an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing R&D towards higher gradients is briefly addressed.