论文标题
监测用NMR在17 Tesla处的NMR的二极化氢化氢化氢化的积累
Monitoring the build-up of hydrogen polarization for polarized Hydrogen-Deuteride (HD) targets with NMR at 17 Tesla
论文作者
论文摘要
我们报告了在春季-8/LEPS上进行光增生性实验的冷冻自旋偏振氢 - 脱二烯（HD）靶标。将少量Ortho-H2（约0.1％）的纯HD气体液化并被液体氦固化。使用稀释冰箱将产生的固体HD的温度降低至约30 MK。将磁场（17 t）应用于HD，以静态方法增长极化。在高温下高温下高清衰老的高磁场强度3个月后，极化冻结后。将几乎所有的Ortho-H2分子转化为para-H2分子，这些分子与HD表现出弱自旋相互作用。如果在衰老过程开始时降低了Ortho-H2的浓度，则可以缩短衰老时间。我们已经开发了一种新的核磁共振（NMR）系统，以测量1H和2H核的放松时间（T1），并在726和111 MHz的相应频率下进行两个频率扫描，并成功地监测了在17 MK时降低的偏光率，以使我们的600至30 MK的极化浓度和浓度达到较低的浓度。高清目标在缩短的衰老时间内。
We report on the frozen-spin polarized hydrogen--deuteride (HD) targets for photoproduction experiments at SPring-8/LEPS. Pure HD gas with a small amount of ortho-H2 (~0.1%) was liquefied and solidified by liquid helium. The temperature of the produced solid HD was reduced to about 30 mK with a dilution refrigerator. A magnetic field (17 T) was applied to the HD to grow the polarization with the static method. After the aging of the HD at low temperatures in the presence of a high-magnetic field strength for 3 months, the polarization froze. Almost all ortho-H2 molecules were converted to para-H2 molecules that exhibited weak spin interactions with the HD. If the concentration of the ortho-H2 was reduced at the beginning of the aging process, the aging time can be shortened. We have developed a new nuclear magnetic resonance (NMR) system to measure the relaxation times (T1) of the 1H and 2H nuclei with two frequency sweeps at the respective frequencies of 726 and 111 MHz, and succeeded in the monitoring of the polarization build-up at decreasing temperatures from 600 to 30 mK at 17 T. This technique enables us to optimize the concentration of the ortho-H2 and to efficiently polarize the HD target within a shortened aging time.
