Energy dissipation during collision for anti-relaxation coatings in alkali-metal vapor cells

Abstract

In this paper, we proposed a method to characterise the coating performance of alkali-metal cells by directly measuring the energy dissipation during collisions between the anti-relaxation coating surface and atoms in the cell. We confirmed that the energy dissipation during collisions is positively correlated with the relaxation characteristics of alkali metals at various temperatures. This discovery is of great significance as it can be utilised to characterise the anti-relaxation coating performance of alkali-metal cells by directly analysing the energy dissipation of anti-relaxation coatings instead of measuring the relaxation time.

Effect of Preparation Processes on Structural Thermal Stability and Collision Energy Dissipation of Common Antirelaxation Coatings on Quartz Substrates

“…There was no uniform temperature increase law for energy dissipation. Our previous work 36 showed that the thermal change of energy dissipation for hexatriacontane coating baked for 15 min matches the temperature-rising trend of the relaxation rate in the paraffin-coated cell, that decreased first and then increased. This phenomenon is inconsistent with the current observation.…”

“…Dong et al observed a correlation between the temperature-rising law of relaxation rate of coated-cells and the collision energy dissipation between the AFM probe tip and the slide coating, where it decreases first and then increases. As a result, this study concludes that energy dissipation can be used to quantitatively evaluate the cell relaxation property and its thermal changes.…”

“…This collision effect is similar to that between the AFM probe tip and sample surface. 35 Dong et al 36 derived a theoretical relationship between the energy E dis dissipated from two collisions and the transverse relaxation time T 2 of alkali atoms, and subsequently confirmed this relationship E T 1/ dis 2 using a paraffin coated-slide and a paraffin coated-cell, both of which were prepared using a single process. From that, our team took an unconventional road by calculating the energy dissipated during the collision between the AFM probe tip and the coating surface to characterize the antirelaxation performance of the cell coating.…”

“…Within the 6 mM concentration group, the real energy dissipation of coatings silanized for 8, 9, 10, and 40 min showed insignificant thermal change below 55 °C, whereas that of coatings silanized for 7 and 20 min fluctuated greatly. Dong et al 36 observed a correlation between the temperature-rising law of relaxation rate of coated-cells and the collision energy dissipation between the AFM probe tip and the slide coating, where it decreases first and then increases. As a result, this study concludes that energy dissipation can be used to quantitatively evaluate the cell relaxation property and its thermal changes.…”

Modelling interactions between rubidium atom and magnetometer cell wall molecules

“…Atomic force microscopy (AFM) has been used by Dong et al 10 to study energy dissipation on the surface coating of a magnetometer cell wall, where the energy dissipation between the AFM tip and the surface coating is assumed approximately equal to the adsorption energy induced by the collision between alkali-metal atoms and the surface coating. They established that the energy dissipation on the coating (paraffin) of the cell surface is related to the relaxation rate of the alkali-metal (Cs atom) vapour cell: The energy dissipation is directly proportional to the square root of the relaxation rate (or inversely proportional to the square root of relaxation time).…”