Development and application of ultra slow muon generation by laser resonant ionization method

激光共振电离法产生超慢μ介子的研制及应用

• 批准号: 11559019
• 负责人: MIYAKE Yasuhiro
• 金额: $ 8.45万
• 依托单位: High Energy Accelerator research Organization (KEK)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11559019/
• 关键词: muon; polarization; spin; ultra slow; solid state physics; Hydrogen; surface; Laser; VUV

We have been collaborating with the RIKEN-RAL muon science group on the ultra slow muon generation by the laser resonant ionization method. Construction of the slow ion optics at Port 3 at RIKEN-RAL muon facility was completed on the summer of 2001. Then we had a chance of muon beam time for 5 days at Port3 where about 5 x 105 surface muons/s beam with a momentum of 27 MeV/c is available. The proton accelerator operates at 50Hz repetition rate, therefore the laser system was operated synchronized with the every second muon pulse(25Hz).We could observe a clear peak only when laser lights were introduced, but not when laser lights were not introduced. Also this peak was observed in the expected TOF and in the expected MASS/Q corresponding to the slow muon.We also measured dependence of the slow muon yield as a function of the difference wavelength. It peaked at 820.4 nm. This evidence is showing that Mu is ionized through the 1s-2p transition. On the other hand, the Lyman-α light for Mu … More was experimentally calibrated by this measurement. This is why we claimed we succeeded in the slow muon generation by the laser resonant ionization method originated from the surface muon beam. During this measurement, the rate of the slow muon was 0.03μ+/s. There are considered several reasons why the rate was so small. The first reason is that a lot of fraction of the surface muon beam is blocked by a collimator with a small aperture. We have to redesign the beam duct without the collimator on the way to the slow ion optics. The second is that we had no time to adjust the momentum of the surface muon so that surface muon stops on the rear surface of the tungsten target.We may have to exchange tangsten foils of 50 and 25μm, since momentum of the surface muon can be reduced by the several beam windows. The third is that we need to improve the VUV (Vacuum Ultra Violet) generation which is lower than one or two order of magnitude compared with the KEK laser system.By improving those experimental conditions, we expect at least 100 to 1000 times larger yield of the slow muons which will be suitable for the μ+SR studies. Less

我们一直与 RIKEN-RAL μ 子科学小组合作，通过激光共振电离法产生超慢 μ 子，RIKEN-RAL μ 子设施 3 号端口的慢离子光学器件的建设于 2001 年夏天完成。有机会在 Port3 进行为期 5 天的 μ 子束时间，其中可提供约 5 x 105 表面 μ 子/s 束，动量为 27 MeV/c。质子加速器以50Hz的重复频率运行，因此激光系统与每秒的μ子脉冲（25Hz）同步运行。只有在引入激光时我们才能观察到清晰的峰值，但在不引入激光时也观察不到该峰值。在对应于慢 μ 子的预期 TOF 和预期 MASS/Q 中观察到。我们还测量了慢 μ 子产率与不同波长的函数关系，该证据表明它的峰值为 820.4 nm。 Mu 通过 1s-2p 跃迁被电离，另一方面，Mu 的莱曼-α 光通过这种测量进行了实验校准，这就是为什么我们声称我们通过激光共振电离方法成功地产生了缓慢的 mu 子。在这次测量中，慢μ子束的速率为0.03μ+/s。有几个原因可以认为速率如此之小，第一个原因是表面的分数很大。 μ 子束被小孔径准直器阻挡，我们必须重新设计没有准直器的束流通道，以达到慢离子光学器件的目的。 μ子停在钨靶材的后表面。我们可能需要更换50μm和25μm的唐箔，因为表面μ子的动量可以通过几个光束窗口来减小。我们需要改进VUV（真空紫外）的产生，与KEK激光系统相比，它的产生量低于一两个数量级。通过改善这些实验条件，我们预计慢μ介子的产量至少提高100到1000倍，将适用于 μ+SR 研究。

项目成果

Y.Miyake et al.: "Construction of the experimental set-up for ultra slow muon generation by Thermal Mu ionization method at RIKEN-RAL"Physica B. 289-290. 666-669 (2000)

Y.Miyake 等人：“在 RIKEN-RAL 通过热 Mu 电离方法构建超慢 μ 子生成实验装置”Physica B. 289-290。

Y. Miyake. K. Shimomura, S. Makimura, Y. Matsuda, P. Bakule, R.J. Scheuermann, and K. Nagamine: "Ultra Slow Muon Generation by Laser Resonant Ionization Towards the 21st Century"Rad. Phys. Chem.. 60/4-5. 521-524 (2001)

Y.三宅。

Y. Miyake: "Ultra Slow Muon Generation by Lyman-a resonant ioniztion method"Jpn. J. Optics. 29, 11. 696-701 (2000)

Y. Miyake：“莱曼的超慢μ介子生成-共振电离方法”Jpn。

Y.Miyake et al.: "Improvement of the detection limit of hydrogen by Lyman-α RIS"Resonance Ionization Spectroscopy. RIS2000. 20-25 (2001)

Y. Miyake 等人：“通过 Lyman-α RIS 改进氢的检测限”共振电离光谱 20-25 (2001)。

Y. Miyake, K Nishiyama, S. Sakamoto, K. Shimomura, R. Kadono, W. Higemoto, K. Fukuchi, S. Makimura, J.L. Bevereidge, K. Ishida, T. matsuzaki, I. Watanabe, Y. Matusda, N, Kawamura, and K. Nagamine: "Muon Science Facility at JKJ Project"Proceedings of the I

Y. Miyake、K Nishiyama、S. Sakamoto、K. Shimomura、R. Kadono、W. Higemoto、K. Fukuchi、S. Makimura、J.L. Bevereidge、K. Ishida、T. matsuzaki、I. Watanabe、Y. Matusda、