Pumping Dynamics of Cold-Atom Experiments in a Single Vacuum Chamber

Abstract

A nonlinear analytical model for the pressure dynamics in a vacuum chamber, pumped with a sputter ion pump (SIP), is proposed, discussed and experimentally evaluated. The model describes the physics of the pumping mechanism of SIPs in the context of a cold atom experiment. By using this model, we fit pump-down curves of our vacuum system to extract the relevant physical parameters characterizing its pressure dynamics. The aim of this investigation is the optimization of cold atom experiments in terms of reducing the dead time for quantum sensing using atom interferometry. We develop a calibration method to improve the precision in pressure measurements via the ion current in SIPs. Our method is based on a careful analysis of the gas conductance and pumping in order to reliably link the pressure readings at the SIP with the actual pressure in the vacuum (science) chamber. Our results are in agreement with the existence of essentially two pumping regimes determined by the pressure level in the system. In particular we found our results in agreement with the well known fact that for a given applied voltage, at low pressures, the discharge current efficiently sputters pumping material from the pump's electrodes. This process sets the leading pumping mechanism in this limit. At high pressures, the discharge current drops and the pumping is mainly performed by the already sputtered material.

Compact chip-scale guided cold atom gyrometers for inertial navigation: Enabling technologies and design study

“…In fact, the vacuum system plays a key role in determining the dead time between measurements. 116,122 For instance, assume that the interferometer uses molasses cooled atoms. If we use a single vacuum chamber, then the expected dead time is on the order of 5 s. If we use a double-chamber vacuum system (2DMOT + 3DMOT), then the dead time can be reduced to less than 1 s. In both cases, if we use evaporatively cooled atoms, then we need to add, typically, at least 3 s to the previous values.…”

“…Basu and Velásquez-Garcia 121 demonstrated microfabricated non-magnetic ion pumps to maintain UHV conditions in miniature vacuum chambers for atom interferometry. Finally, Martin et al 122 investigated the pumping dynamics of sputtered ion pumps. This study describes the main physical pumping mechanisms based on a nonlinear model for the ion-current pump-down dynamics in the low-pressure regime.…”

Enhanced observation time of magneto-optical traps using micro-machined non-evaporable getter pumps

“…2 , the MOT loading curve is acquired each time the B-field is turned ON (to turn on the MOT). Data points of the MOT atom number loading curve are then approximated by an exponential function of time constant used to calculate the background pressure 48 , 49 . All background pressure data points shown in figures of this manuscript were obtained using this approach.…”

Nonadiabatic molecular dynamics simulation of C2H22+ in a strong laser field*

“…Recent advances in the production of extremely ultraintense laser pulse techniques have stimulated an increasing interest in the main problem of laser and matter interaction. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Especially, complete control of molecular dynamic and reaction is one of the central aims of photophysical and photochemical science. Recent progress in laser technology has made time-domain observation of reaction dynamics available.…”