High bandwidth power supplies for optical pumping of francium atoms for atomic parity violation studies

用于钫原子光泵浦的高带宽电源，用于原子宇称违反研究

• 批准号: SAPEQ-2021-00005
• 负责人: Gwinner, Gerald
• 金额: $ 4.98万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Research Tools and Instruments
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742993
• 关键词: bandwidth; power; supplies; optical; pumping

The fundamental forces of nature are one of the fascinating subjects that can be studied at the ISAC radioactive beam facility at TRIUMF, Canada's national laboratory for nuclear and particle physics. In particular, the weak force, causing the beta-decay of nuclei, is unique in exhibiting the phenomenon of parity-violation: the mirror images of physical processes mediated by the weak force are not observed in nature. ISAC offers the possibility to study atomic parity-violation in francium (Fr), an element combining a very heavy nucleus (Z=87) with the simple, essentially hydrogenlike, valence structure of an alkali. Fr nuclei are the least stable among the first 103 elements in the periodic table, the longest-lived isotope decays in only 23 minutes. To make optimum use of the minute sample, the Fr atoms are slowed down with laser light and captured into a `magneto-optical' laser trap, suspended in free space at temperatures millions of times colder than room temperature. We have established a francium trapping facility at ISAC; in collaboration with researchers from the United States and Mexico, we are now using this francium source to carry out a series of precision experiments using laser and microwave spectroscopy. Working our way towards atomic parity violation measurements, we are exciting an exceedingly faint electronic transition, 7s to 8s, and measure its property. For these measurements, the atoms have to be optically pumped with laser light into a quantum state that has the atom's magnetic moment aligned with an externally applied magnetic field. Optical pumping is not compatible with the laser trapping setup, and we have to rapidly, on the order of a millisecond, switch back and forth between magnetic field configurations suitable for laser trapping and optical pumping. For this purpose we require 3 high-current power supplies that can be switched on and off at the hundred microsecond scale to control a three-dimensional coil configuration. With this equipment in place, we can push towards an atomic parity violation experiment in francium.

自然的基本力是令人着迷的课题之一，可以在加拿大国家核与粒子物理实验室 TRIUMF 的 ISAC 放射性束设施中进行研究。特别是，引起原子核β衰变的弱力在表现宇称破坏现象方面是独一无二的：在自然界中没有观察到由弱力介导的物理过程的镜像。 ISAC 提供了研究钫 (Fr) 原子宇称不守恒的可能性，钫是一种将非常重的原子核 (Z=87) 与简单的、本质上类似氢的碱金属价结构结合在一起的元素。 Fr 原子核是元素周期表前 103 种元素中最不稳定的，寿命最长的同位素仅在 23 分钟内衰变。为了充分利用微小的样品，Fr 原子被激光减速并捕获到“磁光”激光陷阱中，该陷阱悬浮在自由空间中，温度比室温低数百万倍。我们在 ISAC 建立了一个钫捕集设施；通过与美国和墨西哥的研究人员合作，我们现在正在利用这种钫源，利用激光和微波光谱法进行一系列精密实验。我们致力于原子宇称不守恒测量，激发了极其微弱的电子跃迁（7 秒到 8 秒），并测量了其特性。对于这些测量，必须用激光将原子光泵入量子态，使原子的磁矩与外部施加的磁场一致。光泵浦与激光捕获装置不兼容，我们必须以毫秒的量级快速在适合激光捕获和光泵浦的磁场配置之间来回切换。为此，我们需要 3 个大电流电源，它们可以在百微秒尺度上打开和关闭，以控制三维线圈配置。有了这些设备，我们就可以推动钫原子宇称破坏实验。