Experimental Status

We have constructed a collector “Paul” trap. This linear quadrupole trap was commissioned in the first week of the year 2007 with the trapping and optical detection of barium ions. Barium is iso-electric to radium and will be used as a guinea pig throughout the experiment. The collector trap is to be efficiently loaded with radium ions. From this trap, single ions will be transported to a precision trap, which has been constructed and commissioned. This trap has the perfect geometry to create the best trapping fields. Before we assembled it, the copper parts were gold coated at GSI!

The actual experiments will take place in the ultra high vacuum, low-noise environment of the precision trap. We are currently working this new trap and associated ion guiding system. Also, we have built the laser system for the radium ion, having almost completed the lasers for barium. We have constructed a linear enhancement cavity to increase the amount of blue barium cooling light, obtained from frequency doubling in PPLN (periodically poled lithium niobiate). mWatts of very nice blue light have been spotted. Also, we are experimenting with high-power LED’s to replace laser diodes on the shelving transitions.

On the theoretical side, we are looking for the best radium isotope to use. This choice will be based on a sound study of all systematic effects. Using AGOR cyclotron, the Trimp group has produced a chain of isotopes around ²¹³Ra. Data analysis is still underway, but yields are good! From the Trimp beamline, we will directly load the collector trap with these particles.

Next step is then spectroscopy of trapped radium ions, for the first time ever! Very recently we have perfomed the spectroscopy of trapped Radium ions in a Radio Frequency Quadrupole cooler and buncher. We have observed the pump and repump transitions of a series of isotopes, namely ²¹²Ra, ²¹³Ra and ²¹⁴Ra.