Resistive and sympathetic cooling of highly-charged-ion clouds in a Penning trap

Abstract

We present measurements of resistive and sympathetic cooling of ion clouds confined in a Penning trap. For resistive cooling of a cloud consisting of one ion species, we observe a significant deviation from exponential cooling behaviour which is explained by an energy-transfer model. The observed sympathetic cooling of simultaneously confined ion species shows a quadratic dependence on the ion charge state and is hence in agreement with expectations from the physics of dilute non-neutral plasmas.

Deceleration, precooling, and multi-pass stopping of highly charged ions in Be+ Coulomb crystals

“…[17][18][19][20][21] This technique is not available for HCI work due to losses by charge exchange. Other work regarding external HCI injection into Penning traps relies on resistive cooling [22][23][24] or proposed electron cooling. 25 These techniques are limited in achievable ion temperatures or not applicable in Paul traps, which are the working horse for the highest accuracy spectroscopy to date.…”

“…Thus, we employ sympathetic cooling 23,24,26,27 of HCIs through collisions with singly charged and continuously lasercooled Be + ions that transfer energy from the injected slow HCI to the cold Be + ions. For this purpose, we have built a cryogenic linear Paul trap CryPTEx 28 and interfaced it with an ion source for HCI production through a deceleration and precooling beamline, as depicted in Fig.…”

Rapid crystallization of externally produced ions in a Penning trap

“…Resistive cooling [1] can be an effective method for such systems, especially if they carry high electric charge. However, the minimal energy is usually limited to energies which correspond to the ambient temperature on the scale of several kelvin [12]. Hence, sympathetic cooling with simultaneously confined laser-cooled ions is a good possibility for these ions to reach the millikelvin regime [1,13].…”