Development of trapping energetic ion beams by using rf ion guide

使用射频离子导向器捕获高能离子束的开发

• 批准号: 12440076
• 负责人: WADA Michiharu
• 金额: $ 8.38万
• 依托单位: RIKEN
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440076/
• 关键词: rf ion guide; RI-Beam; ion trap; gas catcher; イオンガイド; フラグメントセパレータ

The projectile fragment separator (RIPS) at the RIKEN accelerator facility provides a wide variety of RI-beams with less restrictions on their chemical property or lifetime limit. The beam energy and quality is, however, not adequate for low-energy beam experiments, in particular for trapping experiments. We have been working on technical developments toward precision atomic spectroscopy of trapped RI-ions by slowing down the energetic RI-beams provided by the RIPS using a large gas-catcher cell and an rf ion guide system. The high energy beam (〜GeV) is first passed through a degrader and then stopped and thermalized in a large He gas cell (〜100 Torr). The high ionization potential of He guaranties that most ions end up in the singly ionized state. Subsequently, using the ion charge as a handle, we apply dc electric fields to pull the RI-ions to a cathode electrode located at an exit hole, while rf-fields at the cathode electrode keep them away from the surface of the electrode. We tested two types of cathode electrodes and named them rf-funnel and rf-carpet depend on their structure. On-line tests of the rf ion-guide system have been performed at the RIPS facility which provides a 70 MeV/u Li-8 ion beam with a typical intensity of -10^6 atoms/s. An overall efficiency of 1% was obtained so far, when the beam intensity was weak. A decrease of the efficiency was observed as increasing the beam intensity. This effect was partially compensated by decreasing the impurities by employing a cold trap in the cell.

Riken Accelerator设施的弹丸碎片分离器（RIP）提供了各种各样的RI梁，其化学性质或终生限制的限制较少。但是，梁的能量和质量不足以进行低能束实验，特别是用于捕获实验。我们一直在通过使用大型气体捕捉器细胞和RF离子指南系统降低撕裂提供的能量RI光束，从而朝着捕获的RI-ION的精确原子光谱进行技术发展。高能梁（〜GEV）首先通过降解器，然后在大型HE燃气池（〜100 Torr）中停止并进行热效。他的高电离潜力保证大多数离子最终处于单元化状态。随后，使用离子电荷作为手柄，我们使用直流电场将RI-ION拉到位于出口孔的阴极电极上，而在阴极电极处的RF场使它们远离电子表面。我们测试了两种类型的阴极电极，并将其命名为RF-Funnel，RF-Carpet取决于它们的结构。 RF离子指南系统的在线测试已在RIPS设施中进行，该设施提供了70 MeV/U Li-8离子束，典型强度为-10^6 itoms/s。到目前为止，当梁强度较弱时，总体效率为1％。观察到效率的降低是因为增加了光束强度。通过在细胞中使用冷陷阱来减少杂质，从而部分补偿了这种效果。

项目成果

T.Nakamura, M.Wada, ,K.Okada, I.Katayama, S.Ohtani, H.A.Schuessler: "Precision spectroscopy of the Zeeman splittings of the $*9$Be$*+$$2-2$S$_{l/2}$ hyperfine structure for nuclear structure studies"Opt. Comm.. 205. 329-336 (2002)

T.Nakamura、M.Wada、、K.Okada、I.Katayama、S.Ohtani、H.A.Schuessler：“$*9$Be$* $$2-2$S$_{l 的塞曼分裂的精密光谱

K.Okada et al.: "Acceleration of the chemical reaction of trapped Ca^+ ions with H2O molecules by laser excitation"J. Phys. B. 36. 33-46 (2003)

K.Okada 等人：“通过激光激发加速捕获的 Ca 离子与 H2O 分子的化学反应”J。

T. Nakamura, S. Ohtani, M. Wada, K. Okada, I. Katayama, and H. A. Schuessler: "Ion dynamics and oscillation frequencies in a linear combined trap"J. App.Phys.. 89. 2922-2931 (2001)

T. Nakamura、S. Ohtani、M. Wada、K. Okada、I. Katayama 和 H. A. Schuessler：“线性组合陷阱中的离子动力学和振荡频率”J。

M.Wada, Y.Ishida, T.Nakamura, Y.Yamazaki, T.Kambara, H.Ohyama, Y.Kanai, T. M.Kojima, Y.Nakai , N.Ohshima, A.Yoshida, T.Kubo, Y.Matsuo, Y.Fukuyama, K.Okada , T.Sonoda, S.Ohtani, K.Noda, H.Kawakami I.Katayama: "Slow RI-beams from projectile fragment separat

M.Wada、Y.Ishida、T.Nakamura、Y.Yamazaki、T.Kambara、H.Ohyama、Y.Kanai、T.M.Kojima、Y.Nakai、N.Ohshima、A.Yoshida、T.Kubo、Y.Matsuo

K.Okada, M.Wada et al.: "Minimization of Trapped Ion Loss with a Cryogenic Linear Ion Trap"Japanese Journal of Applied Physics. 40. 4221-4222 (2001)

K.Okada、M.Wada 等人：“利用低温线性离子阱最小化捕获离子损失”日本应用物理学杂志。