R&D of High Resolution Calorimeter for Electron-Positron Collider in TeV Region

为下一代正负电子对撞机实验进行了量热计的研发研究。构建了一个原型模块，该模块由铅和增透纤维组成。它具有电磁簇射和强子簇射的综合作用。为了获得较好的强子簇射能量分辨率，铅纤维和石墨纤维的组成为4：1。利用高能物理国家实验室的质子同步加速器试验束流装置对该装置的基本性能进行了测试。所使用的光束是电子和负π介子的1 GeV至4 GeV。各种属性，如能量分辨率，位置分辨率，并依赖于入射位置进行了测量。在1GeV入射能量下，对电子（π介子）的能量分辨率为14%（50%）。强子能量分辨中包含了12%的常数项，这主要是由于簇射泄漏。将实验结果与GEANT模拟程序的计算结果进行了比较，两者吻合较好。根据侧簇射发展的信息和预簇射输出，实现了电子与π介子的分离。在对量热器本身进行研究的同时，还对能在强磁场中工作的光子探测器件进行了研究，根据束流测试结果，从物理分析的角度，我们发现原型量热器能满足各种要求。然而，应该指出的是，大规模生产的方法和降低成本的可能性还没有在这里进行研究，这将是未来的问题。

R&D study of a calorimeter has been performed for the next generation electron-positron collider experiment. A prototype module was constructed which consisted of lead and scintillating fibers. It had a combined function both for electromagnetic shower and for hadronic shower. In order to obtain a good energy resolution for hadronic shower, the composition of lead and scintillating fibers was arranged to be 4 : 1. Basic performances were tested using the test beam facility of Proton Synchrotron at National Laboratory for High Energy Physics (KEK). The beams used were electron and negative pions of 1 GeV to 4 GeV.Various properties such as energy resolution, position resolution, and dependence on the incident position were measured. The energy resolution of 14% (50%) at 1GeV incident energy was obtained for electrons (pions). The constant term of 12% was included in the hadronic energy resolution, which was mainly due to the shower leakage. The results obtained in the beam test were compared with the predictions of GEANT simulation program, and the good agreement was obtained.Based on information of lateral shower development and on pre-shower output, the separation between electrons and pions was performed. The separation was also tried by using the time information of the shower development.In parallel with the study of the calorimeter itself, the photon detection devices were also investigated which can be operated in the strong magnetic fields.Based on the beam test results, we found that the prototype calorimeter would satisfy the various requirements from the viewpoint of physics analyzes. It should be noted, however, that the method of mass-production and possibility of cost-down have not been investigated here and will be the future issues.