CERN利用晶体效应对正电子源进行的实验研究总结
Summary of experimental studies at CERN on a positron source using crystal effects
摘要：
在CERN的WA103实验中，研究了一种用于未来直线对撞机的新型正电子源，其转换器是一个轴向取向的钨晶体<111>。在这样的源中，产生$e^+ e^-$对的光子来自沟道辐射和相干韧致辐射。在实验中，用6GeV和10GeV的电子束轰击不同类型的靶：4mm厚的晶体靶、8mm厚的晶体靶和复合靶（4mm厚的晶体+4mm厚的非晶盘）。还使用20 mm厚的非晶钨靶与8 mm晶体进行比较。在磁场中，用漂移室探测和分析出射带电粒子的轨迹。能量和角度谱的正电子获得的能量高达150兆电子伏和角度高达30度。测量的正电子在动量空间（纵向与横向）的分布也被提出，给出一个完整的动量空间描述的源。还提出了关于出射光子的结果。清楚地观察到光子和正电子产生的显着增强。在10GeV入射能量下，4mm晶体的正电子增强因子为4，8mm晶体的正电子增强因子约为2。此外，晶体过程的模拟程序验证了相当好的协议之间的模拟和实验光谱，无论是对正电子和光子。
英文摘要：
New kind of positron sources for future linear colliders, where the converter is a tungsten crystal oriented on the <111> axis, has been studied at CERN in the WA103 experiment. In such sources the photons which create the $e^+ e^-$ pairs result from channeling radiation and coherent bremsstrahlung. In this experiment electron beams of 6 and 10 GeV were sent on different kinds of targets: a 4 mm thick crystal, a 8 mm thick crystal and a compound taraget (4 mm crystal + 4 mm amorphous disk). An amorphous tungsten target 20 mm thick was also used for comparison with the 8 mm crystal. Tracks of outgoing charged particles were detected and analyzed by a drift chamber in a magnetic field. The energy and angle spectra of the positrons were obtained for energies up to 150 MeV and angles up to 30 degrees. The measured positron distribution in momentum space (longitudinal versus transverse) is also presented, giving a full momentum space description of the source. Results on outgoing photons are also presented. A significant enhancement of both photon and positron production is clearly observed. At 10 GeV incident energy, the positron enhancement factor is 4 for the 4 mm crystal, about 2 for the 8 mm crystal. Besides, the simulation code for the crystal processes is validated by a quite good agreement between the simulated and experimental spectra, both for positrons and photons.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
