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Title: Accurate measurement of the sticking time and sticking probability of Rb atoms on a polydimethylsiloxane coating

We present the results of a systematic study of Knudsen’s flow of Rb atoms in cylindrical capillary cells coated with a polydimethylsiloxane (PDMS) compound. The purpose of the investigation is to determine the characterization of the coating in terms of the sticking probability and sticking time of Rb on the two types of coating of high and medium viscosities. We report the measurement of the sticking probability of a Rb atom to the coating equal to 4.3 × 10{sup −5}, which corresponds to the number of bounces 2.3 × 10{sup 4} at room temperature. These parameters are the same for the two kinds of PDMS used. We find that at room temperature, the respective sticking times for high-viscosity and medium-viscosity PDMS are 22 ± 3 μs and 49 ± 6 μs. These sticking times are about million times larger than the sticking time derived from the surface Rb atom adsorption energy and temperature of the coating. A tentative explanation of this surprising result is proposed based on the bulk diffusion of the atoms that collide with the surface and penetrate inside the coating. The results can be important in many resonance cell experiments, such as the efficient magnetooptical trapping ofmore » rare elements or radioactive isotopes and in experiments on the light-induced drift effect.« less
Authors:
;  [1]
  1. Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation)
Publication Date:
OSTI Identifier:
22472441
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Experimental and Theoretical Physics; Journal Volume: 120; Journal Issue: 1; Other Information: Copyright (c) 2015 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADSORPTION; ATOMS; CYLINDRICAL CONFIGURATION; DIFFUSION; MAGNETO-OPTICAL EFFECTS; ORGANIC POLYMERS; PROBABILITY; SURFACES; TEMPERATURE RANGE 0273-0400 K; TRAPPING; VISCOSITY; VISIBLE RADIATION