Prospects for Ultra-Stable Timekeeping with Sealed Vacuum Operation in Multi-Pole Linear Ion Trap Standards; Conference paper

摘要

A recent long-term comparison between the compensated multi-pole Linear Ion Trap Standard (LITS) and the laser-cooled primary standards via GPS carrier-phase time transfer showed a deviation of less than 2.7x10(-17)/day. A subsequent evaluation of potential drift contributorsin the LITS showed that the leading candidates are fluctuations in background gases and the neon buffer gas. The current vacuum system employs a 'flow-through' turbo-molecular pump and a diaphragm fore-pump.Here, we consider the viability of a 'sealed' vacuum system pumped by a non-evaporable getter for long-term ultra-stable clock operation. Initial tests suggest that both further stability improvement and longermean-time- between-maintenance can be achieved using this approach.