New investigations of polarized solid HD targets
New investigations of polarized solid HD targets
复制标题
偏振固体高清目标的新研究
DOI：
10.1016/0168-9002(94)01441-8
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发表时间：
1995
影响因子：
1.4
通讯作者：
C. Whisnant
中科院分区：
文献类型：
--
作者：
A. Honig;Q. Fan;X. Wei;A. Sandorfi;C. Whisnant
冻结旋转模式下的极化固体高清靶具有优越的核物理特性和简单的操作配置，但由于靶的生产时间与使用时间不成比例，因此其部署受到限制。上级核物理特性和简单的操作配置。最近的调查已经取得了冻结自旋极化寿命，在一个方便的目标温度为1.5 K，近一年的H和D在高控股领域，并在子特斯拉控股领域超过一个星期。这些结果，结合新的有趣的自旋物理学的出现，使用相对较弱的电离束，如偏振光子束，消除了上述障碍，并打开了使用偏振固体HD长时间的核自旋物理实验。可以产生大的多个目标，从具有冷传输（4K）设备的极化产生装置中取回，在廉价的（1.5K，7 T）低温恒温器中存储非常长的时间，并且通过便携式冷传输装置将“现成的”引入束内低温恒温器中。报告了用于实现偏振H和/或D的各种模式，以及已经实现的和预期的偏振值。实验结果给出了Kapitza电阻之间的固体HD和冷却丝需要获得低温在热演化极化过程中。15 mK可以使用镀金的铝线来实现，其构成了可极化H或D核子数量的15%的外来核子。也考虑了对更高电离束的应用。
Polarized solid HD targets in a frozen-spin mode, with superior nuclear physics characteristics and simple operational configurations, have previously been restricted in their deployment due to a disproportionate target production time with respect to utilization time. Recent investigations have yielded frozen-spin polarization lifetimes, at a convenient target temperature of 1.5 K, of nearly a year for both H and D at high holding fields, and of more than a week at sub-Tesla holding fields. These results, taken together with the advent of new interesting spin-physics using relatively weakly ionizing beams, such as polarized photon beams, remove the above impediment and open up the use of polarized solid HD to long duration nuclear spin-physics experiments. Large, multiple targets can be produced, retrieved from the polarization-production apparatus with a cold-transport (4 K) device, stored for very long times in inexpensive (1.5 K, 7 T) cryostats, and introduced “off-the-shelf” into in-beam cryostats via the portable cold-transport apparatus. Various modes for achieving polarized H and/or D, as well as already achieved and expected polarization values, are reported. Experimental results are given on Kapitza resistance between the solid HD and the cooling wires necessary to obtain low temperatures during the heat-evolving polarization process. 15 mK is achievable using gold-plated aluminum wires, which constitute 15% extraneous nucleons over the number of polarizable H or D nucleons. Application to more highly ionizing beams is also given consideration.