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Development of Polarized Internal Target

偏振内部靶的开发

基本信息

批准号：
03554003
负责人：
TAMAE Tadaaki
金额：
$ 10.5万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

At the first stage of development of a polarized target, we polarized a vapored alkaline-metal with a circularly polarized laser beam. A spin-exchange cell of Pyrex glass was coated with a drifilm from dichloro-dimethyl-silane plus water to avoid depolarization. Rubidium atoms were optically-pumped in a magnetic field of 3,000 gauss in a solenoid coil to reduce the radiation trapping effect.Polarizations of rubidium atoms, deuterium atoms and deuterons are needed to be measured for assessment of the performance. We constructed a system to measure the polarization and gas-thickness using Faraday rotation and evaluated them under various conditions. The system can decide the rotation angle within an error of 0.01ﾟ. A rotation angle of 0.56 degrees was observed for vacant threefold cells of total 1.4 cm thickness in 2 k gauss at the wavelengthy of 780.8nm. The Verdet constant of Pyrex glass was obtained to be 2*10^<-4> degrees/gauss・cm from the result. For the rubidium atoms, our preliminary result showed a polarization of 0.4 at a gass thickness of 4*10^<13> atoms/cm^2.Deuterium molecules are dissociated into atoms at the first stage. An rf dissociation system was constructed for its sake. In a mass spectrum measured by a quadrupole mass spectrometer, a peak of a mass number of 2 was observed. It showed that the molecules were dissociated into atoms in the system. However the peak disappeared after a short time, because the coating was destroyed by rf or activated deuterium atoms. It is one of probelms to be solved for the development of the polarized target how the coating is protected from such a destruction.We are also developing a Lamb-shift polarimeter to measure the polarization of the deuterium nucleus (deuteron).

在偏振靶研制的第一阶段，我们用圆偏振激光束对蒸发的碱金属进行了偏振。为了避免去极化，用二氯二甲基硅烷加水涂覆了一层自旋交换膜。为了减小辐射俘获效应，在螺线管线圈中，在3000高斯的磁场中光泵浦Rb原子。为了评估性能，需要测量Rb原子、De原子和De的极化。我们构建了一套利用法拉第旋转测量偏振和气体厚度的系统，并在不同的条件下对其进行了评估。该系统可以在0.01ﾟ的误差范围内确定转角。在波长780.8 nm处，在2k高斯下观察到总厚度为1.4 cm的三重空腔的旋转角为0.56度。结果表明，该玻璃的Verdet常数为2*10；-4度/高斯·cm。对于Rb原子，我们的初步结果显示，当GaS厚度为4*10^&lt；13&gt；/cm2时，极化强度为0.4。为此，我们构建了一个射频解离系统。在用四极质谱计测量的质谱图中，观察到质量数为2的峰。结果表明，在该体系中，分子解离成原子。但在很短的时间内，由于涂层被射频或活化的氘原子破坏，峰消失了。如何保护涂层免受这种破坏，是偏振靶研制过程中需要解决的问题之一。我们还在研制一种兰姆式偏振测量仪，用于测量氚核(氚)的极化。