An efficient method for producing ⁹Be⁺ ions using a 2 + 1 resonance-enhanced multiphoton ionization process

Abstract

We report a method of creating pure 9Be+ ions by a 2+1 resonance-enhanced multiphoton ionization (REMPI) for the ionization potential of 75192.64(6) cm-1 (133 nm). The efficient generation of 9Be+ ions has been realized in a segmented linear ion trap. The average loading rates with a 10 ns, 1 mJ laser at 310 nm and 306 nm are 3.8 and 1.3 ions per pulse, respectively. This method has the advantage of reducing the electron contamination to the ion trap electrodes greatly. It also reduces the requirement of single-photon energy while satisfying the need for ionization probability and can be applied to other atoms with high ionization thresholds.

Dynamic laser ablation loading of a linear Paul trap

“…The distance from the calcium target to the entrance end cap is 55 mm. A diodepumped pulsed laser at wavelength 1064 nm, with the energy of ∼110 µJ/pulse and 8 ns duration, has a Gaussian spatial profile and is focused to a 1/e 2 diameter of 80 (10) µm on a calcium target. The ablation laser energy is monitored by an energy meter (Coherent, FieldMaxII) and the laser is operated at a stable condition but with a large energy of about 20 mJ.…”

“…When the pulse energy of the ablation laser is below 70 (10) µJ, no ion is loaded into the ion trap due to the low fluence of the ablation laser. The ablation threshold for successfully loading ions is then obtained to be 1.4(3) J cm −2 with the ablation laser spot size of 80 (10) µm, which is consistent with the ablation threshold of metal targets [49].…”

“…When the pulse energy of the ablation laser is below 70 (10) µJ, no ion is loaded into the ion trap due to the low fluence of the ablation laser. The ablation threshold for successfully loading ions is then obtained to be 1.4(3) J cm −2 with the ablation laser spot size of 80 (10) µm, which is consistent with the ablation threshold of metal targets [49]. At the low energy range of 70 and 90 µJ of the ablation laser, the numbers of Ca + ions loaded and accumulated in the ion trap increase with almost equal quantities for each ablation laser pulse.…”

“…A conventional method for loading ions into an ion trap consists of the production and ionization of atoms. A neutral flux of atoms is commonly produced from a resistively heated oven, and atoms are ionized in the trap via electron impact [7,8] or photoionization [9,10]. The heated oven is typically operated for tens of seconds and at temperatures over several hundred Kelvin, resulting in a significant heating background and limited application in a cryogenic environment.…”

Investigation of spatial structure and sympathetic cooling in the 9Be+–40Ca+ bi-component Coulomb crystals

“…[21] The 9 Be + ions are then loaded into the ion trap by photoionizing the atomic Be beam produced by a Be oven. [22] The trapped 9 Be + ions are sympathetically cooled by the ultracold 40 Ca + ions to form a 9 Be + -40 Ca + bicomponent CC. The 9 Be + ions appear as a dark core in the center area of the bi-component CC if the 313 nm laser is not introduced or at large detuning from the 9 Be + resonance.…”