Study on the Quark-Gluon Structure of Hadrons

为了研究核子的自旋结构和强子的夸克-胶子结构，我们正在准备欧洲核子研究中心的COMPASS(公共结构和光谱Muon质子装置)国际合作计划的实验。COMPASS计划的主要实验之一是通过测量极化µ子在极化核子上的深度非弹性散射的开放魅力产生的截面不对称性来获得核子中的胶子极化。在这次COMPASS合作中，我们负责开发和建造新的极化氢靶系统和束流跟踪探测器系统，以精确地确定入射在极化目标上下游的Mu子的位置。为了测量胶子极化，必须在4*4 cm×22…的探测区域内以小于0.5 mm的空间分辨率确定Muon的轨迹每秒超过10^8个介子。闪烁光纤跟踪探测器从良好的时间和空间分辨率，甚至在极高的计数率条件下都被认为是适用于这些要求的。在本研究项目中，我们研究了将塑料闪烁光纤跟踪探测器系统与位置敏感光电倍增器相结合用于COMPASS实验。利用塑料闪烁光纤与多阳极型位置灵敏光电倍增器(Hamamatsu：H6568)连接，构成了一个跟踪探测器的原型系统，并在Kiek和CERN分别测试了450 MeV/c电子和3.6GeVk质子和介子的特性，在3.6×10^7p/溢出110 mm^2的束流强度下，获得了680PSEC的时间分辨率，适用于指南针实验。为此，我们在本项目中为2000年开始的罗盘实验搭建了基于该类型的光束跟踪器系统。较少

We are now preparing the experiment of the COMPASS(COmmon Muon Proton Apparatus for Structure and Spectroscopy) international collaboration program at CERN in order to investigate the spin structure of the nucleon as well as the quark-gluon structure of hadrons. One of the main experiments of the COMPASS program is to obtain the gluon polarization in the nucleon from the measurement of the cross-section asymmetry for the open charm production in the deep inelastic scattering of polarized muons on polarized nucleons.In this COMPASS collaboration, we are responsible for developing and constructing the new polarized hydrogen target system with a large opening solid angles of 180 nirad and the beam tracker detector system to determine the positions of incident muons precisely at the upstream and the downstream of the polarized target. To measure the gluon polarization, the tracks of muons must be determined in the spatial resolution of less than 0.5 mm in the detection area of 4 * 4 cm^22 … More under more than 10^8 incident muons per second. The scintillation fiber tracking detectors are considered to be applicable for these requirements from the good time and spatial resolution even in the extremely high counting rate condition.In the present research project we have investigated the plastic scintillation fiber tracking detector system combined with position-sensitive photo-multipliers to be used in the COMPASS experiment. A prototype tracking detector system was constructed by using plastic scintillation fibers connected to multi-anode type position-sensitive photo-multipliers(HAMAMATSU : H6568)and tested the characteristics with 450 MeV/c electrons at KIEK and 3.6 GeVk protons and pions at CERN.From the measurement, the time resolution of 680 psec was obtained for the beam intensity of 3.6*10^7 p/spill 110 mm^2, which is applicable for the use in the COMPASS experiment. Therefore, we have constructed the beam tracker system based on this type in this project for the start of the COMPASS experiment in 2000. Less