Estimation of the ion-trap assisted electrical loads and resulting BBR shift

Abstract

Capacitive, inductive and resistive loads of an ion-trap system, which can be modelled as LCR circuits, are important to know for building a high accuracy experiment. Accurate estimation of these loads is necessary for delivering the desired radio frequency (RF) signal to an ion trap via an RF resonator. Of particular relevance to the trapped ion optical atomic clock, determination of these loads lead to accurate evaluation of the Black-Body Radiation (BBR) shift resulting from the inaccurate machining of the ion-trap itself. We have identified different sources of these loads and estimated their values using analytical and finite element analysis methods, which are found to be well in agreement with the experimentally measured values. For our trap geometry, we obtained values of the effective inductive, capacitive and resistive loads as: 3.1 μH, 3.71 (1) μH, 3.68 (6) μH; 50.4 pF, 51.4 (7) pF, 40.7 (2) pF; and 1.373 Ω, 1.273 (3) Ω, 1.183 (9) Ω by using analytical, numerical and experimental methods, respectively. The BBR shift induced by the excess capacitive load arising due to machining inaccuracy in the RF carrying parts has been accurately estimated, which results to a fractional frequency shift of 6.6 × 10−17 for an RF of 1 kV at 2π × 15 MHz and with ±10 μm machining inaccuracy. This needs to be incorporated into the total systematic uncertainty budget of a frequency standard as it is about one order of magnitude higher than the present precision of the trapped ion optical clocks.

An easy to construct sub-micron resolution imaging system

“…The design can be adapted over visible to near-infrared wavelengths in different applications which require sub-micron spatial resolution and high quality images. The described imaging system will be used to image single Ytterbium-ion using its fluorescence at the wavelength 369.5 nm in our optical clock experiment 29 .…”

A New Measurement Method for High Voltages Applied to an Ion Trap Generated by an RF Resonator

“…Therefore, even with these approaches using capacitive voltage dividers, the absolute voltage of the RF amplitude remains unknown until the secular frequency can be measured with trapped ions, and there is a potential threat to cause damage to a surface trap. For metrology purposes, it is also very important to model the electrical properties of the combined helical resonator and trap [31]. Apriyana et al [32] designed an RF circuit to apply correct voltages to ion traps.…”