Exploring the Maximum Ion Rate Through TAMUTRAP’s RFQ*

Radio-frequency quadrupoles (RFQs) are crucial in cooling, bunching, and focusing continuous beams of charged particles by utilizing alternating radio-frequency (RF) electric fields. The larger objective of this research is to develop an RFQ that produces bunches of 10^6 ions for the He6CRES (Cyclotron Radiation Emission Spectroscopy) experiment at the University of Washington. With their focus on accurately measuring beta-decay spectra, the higher ion bunching rate aims to significantly reduce the runtime required for sufficient data collection, which calculations previously expected to take over a year of continuous operation. A successful upgrade of the RFQ will enable the incorporation of a Penning trap in the CRES experiment, which would address dominant sources of systematic uncertainty in the measurement, greatly improving the sensitivity to physics beyond the standard model. 

In this specific project, my primary focus was to measure and optimize the efficiency of the RFQ as we increased the source intensity. To achieve this, we manipulated electrode values within the beamline to determine the maximum ion intensity before space-charge effects overload the system. For our analysis, we installed Micro-Channel Plates (MCPs) before and after the RFQ utilizing high-resolution imaging and timing techniques to assess efficiency. However, we encountered some challenges with the RFQ that prevented us from directly measuring its efficiency. As a result, this poster will detail how we characterized the initial beam from an offline ion source. Specifically, we focused on identifying the optimal settings for a stable source and compared the obtained beam size with Simion calculations using the MCP before the RFQ. Moving forward, the subsequent steps of this research focus on studying the effects of bunching and examining the relationship between efficiency and intensity.