Cryogenic linear Paul trap for cold highly charged ion experiments

Abstract

Storage and cooling of highly charged ions require ultra-high vacuum levels obtainable by means of cryogenic methods. We have developed a linear Paul trap operating at 4 K capable of very long ion storage times of about 30 h. A conservative upper bound of the H(2) partial pressure of about 10(-15) mbar (at 4 K) is obtained from this. External ion injection is possible and optimized optical access for lasers is provided, while exposure to black body radiation is minimized. First results of its operation with atomic and molecular ions are presented. An all-solid state laser system at 313 nm has been set up to provide cold Be(+) ions for sympathetic cooling of highly charged ions.

Cold highly charged ions in a cryogenic Paul trap

“…Spectroscopy of the fluorescent light emitted by the electron-impact excited ions can yield sub-ppm accuracy for the absolute determination of transition wavelengths [4,5]. After such preliminary work we propose to exploit this system for a competitive search for ATV by performing laser spectroscopy of laser-cooled Ir 17+ trapped in a cryogenic Paul trap that was newly constructed for the purpose of trapping HCIs [24]. Quantum logical readout will be applied for ultimate sensitivity [6].…”

Two-dimensional ion crystals in radio-frequency traps for quantum simulation

“…For several types of ion-trap experiments, even small amounts of micromotion can have significant harmful effects: it can lead to large systematic Doppler shifts in ion-based atomic clocks [44,45], and it can substantially reduce the fidelities of quantum gates during a quantum computation (in the absence of advanced micromotion-correcting protocols) [46,47]. Nevertheless, many successful experiments do not depend sensitively on micromotion amplitude [48][49][50][51][52], and ion Coulomb crystals of up to 10 5 − 10 6 particles have been confined in rf Paul traps [53,54]. This section will demonstrate that for carefully chosen parameters (such as those introduced above), micromotion effects on 2D quantum simulation experiments are both predictable and small.…”

Identification of the Predicted5s−4fLevel Crossing Optical Lines with Applications to Metrology and Searches for the Variation of Fundamental Constants

“…These steps enable follow-up laser spectroscopic studies suitable for optical clock applications. For this purpose, we have recently commissioned an experiment in which HCIs were extracted from an EBIT into a novel cryogenic Paul trap [13] where they were sympathetically laser cooled into Coulomb crystals at temperatures of few mK [46], thus preparing HCIs for quantum-logic readout schemes similar to that of Ref. [16].…”

“…In most of the proposed HCIs with atomic number Z ¼ 55-98 and in charge states from 7 to 35, the complex electronic structures are experimentally unknown, and accurate calculations are extremely difficult. In view of novel techniques for sympathetically cooling HCIs in Paul traps [13][14][15] aiming at quantum logic spectroscopy on highly forbidden transitions [16], such data are urgently required.Observations from quasar absorption spectra have suggested a spatial variation of the value of the fine-structure constant α over cosmological dimensions [17], characterized by a dipolar distribution with a value of 10 −6 GLyr −1 . Laboratory experiments [18][19][20][21] have not yet reached the accuracy needed to test this dipolar pattern, which translates to a temporal variation of 10 −19 yr −1 [22] due to the motion of the Earth.…”

“…In most of the proposed HCIs with atomic number Z ¼ 55-98 and in charge states from 7 to 35, the complex electronic structures are experimentally unknown, and accurate calculations are extremely difficult. In view of novel techniques for sympathetically cooling HCIs in Paul traps [13][14][15] aiming at quantum logic spectroscopy on highly forbidden transitions [16], such data are urgently required.…”