Laser-Based High-Voltage Measurements with 1 ppm Accuracy

我们的目标是测量10千伏到100千伏范围内的高电压，相对精度至少为1E-6(1ppm)。为了实现这一点，在离子束中制备特定速度类的离子，使其处于特定的原子状态，然后用这种高电压加速。确定了加速前后的多普勒频移，其变化与离子通过外加电势差时速度的变化相对应。利用这种方法，我们可以将高压测量追溯到一个离子(Ca+/In+)的光学跃迁。这种可追溯性不仅适用于计量机构，也适用于需要极其精确的高压测量的高精度物理实验。例如，卡特林实验测量卡尔斯鲁厄中的电子-反中微子质量，或在存储环上对电子冷却离子进行精密实验。拟议的项目是基于对申请者的早期研究和发表的研究，这些研究已经表明，与其他小组使用这项技术进行的先前研究相比，该研究有了显著的改善。对剩余的系统不确定性进行了详细分析后，列出了一系列离子束生产线的技术改进，以消除或减少它们的影响。此外，将实施和测试一种新的测量方案，使用拉曼跃迁来填充Ca+离子中激发的亚稳态3d态，并利用EOM边带进行快速扫描。这将使我们能够进一步提高测量精度。在为期三年的项目中，拟议的修订将在一项博士研究的框架内实施，并将研究其对基于激光的高压测量的影响。

We aim to measure high voltages in the range of 10 kV to 100 kV with a relative accuracy of at least 1E-6 (1 ppm). To achieve this, ions of a specific velocity class inside an ion beam are prepared in a particular atomic state and then accelerated with this high voltage. The Doppler shift prior to and after the acceleration is determined and its change corresponds to the change of the ions velocity while passing through the applied potential difference. With this approach we can trace back the high voltage measurement to an optical transition in an ion (Ca+/In+). This traceability is of great interest for metrology institutes but also for high-precision experiments in physics that require extremely accurate high voltage measurements. Examples are the KATRIN experiment for the measurement of the electron-antineutrino mass in Karlsruhe or precision experiments on electron-cooled ions at storage rings. The proposed project is based on earlier and published studies of the applicant, which already demonstrated a significant improvement compared to previous studies performed by other groups with this technique. A detailed analysis of the remaining systematic uncertainties resulted in a list of technological improvements of the ion beam line to remove or reduce their influence. Moreover, a new measurement scheme will be implemented and tested, employing a Raman transition to populate the excited metastable 3d state in the Ca+ ion and a fast scanning procedure utilizing EOM sidebands. This will allow us to further improve the measurement accuracy.During the three-year project the proposed amendments will be implemented in the framework of a doctoral study and their implications for the laser-based high-voltage measurements will be studied.