skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Multistage Zeeman deceleration of hydrogen atoms

Abstract

The deceleration of beams of neutral particles possessing an electron spin with time-dependent inhomogeneous magnetic fields is demonstrated experimentally. Half the kinetic energy of a velocity-selected part of a pulsed supersonic beam of hydrogen atoms in the ground state is removed using six pulsed magnetic field stages.

Authors:
 [1];  [2]; ; ; ;  [1]
  1. Physical Chemistry, ETH Zuerich, CH-8093 Zuerich (Switzerland)
  2. (France)
Publication Date:
OSTI Identifier:
20982220
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.031402; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ACCELERATION; ATOMIC BEAMS; ATOMS; ELECTRONS; GROUND STATES; HYDROGEN; KINETIC ENERGY; MAGNETIC FIELDS; NEUTRAL PARTICLES; SPIN; TIME DEPENDENCE; ZEEMAN EFFECT

Citation Formats

Vanhaecke, Nicolas, Laboratoire Aime Cotton, batiment 505, Campus d'Orsay, 91405 Orsay, Meier, Urban, Andrist, Markus, Meier, Beat H., and Merkt, Frederic. Multistage Zeeman deceleration of hydrogen atoms. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.031402.
Vanhaecke, Nicolas, Laboratoire Aime Cotton, batiment 505, Campus d'Orsay, 91405 Orsay, Meier, Urban, Andrist, Markus, Meier, Beat H., & Merkt, Frederic. Multistage Zeeman deceleration of hydrogen atoms. United States. doi:10.1103/PHYSREVA.75.031402.
Vanhaecke, Nicolas, Laboratoire Aime Cotton, batiment 505, Campus d'Orsay, 91405 Orsay, Meier, Urban, Andrist, Markus, Meier, Beat H., and Merkt, Frederic. Thu . "Multistage Zeeman deceleration of hydrogen atoms". United States. doi:10.1103/PHYSREVA.75.031402.
@article{osti_20982220,
title = {Multistage Zeeman deceleration of hydrogen atoms},
author = {Vanhaecke, Nicolas and Laboratoire Aime Cotton, batiment 505, Campus d'Orsay, 91405 Orsay and Meier, Urban and Andrist, Markus and Meier, Beat H. and Merkt, Frederic},
abstractNote = {The deceleration of beams of neutral particles possessing an electron spin with time-dependent inhomogeneous magnetic fields is demonstrated experimentally. Half the kinetic energy of a velocity-selected part of a pulsed supersonic beam of hydrogen atoms in the ground state is removed using six pulsed magnetic field stages.},
doi = {10.1103/PHYSREVA.75.031402},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. Inmore » combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for {sup 20}Ne and {sup 22}Ne.« less
  • Hydrogen atoms in supersonic expansions with velocities in the range from 700 to 800 m/s have been excited to Rydberg-Stark states with principal quantum number n between 20 and 40, decelerated to zero velocity in the lab frame using time-dependent inhomogeneous electric fields, and trapped in a two-dimensional electrostatic trap with an initial density of {approx_equal}5x10{sup 6} cm{sup -3}. The motion of the atomic cloud in the trap was observed by measuring the times of flight and images of the H{sup +} ions produced by pulsed field ionization. The velocity distribution of the trapped atoms can be described by anmore » effective temperature of 350 mK. The decay of the population of trapped atoms does not follow a single-exponential behavior and has contributions from radiative and collisional processes.« less
  • Hydrogen and deuterium atoms in supersonic jet expansions have been decelerated using a multistage Zeeman decelerator. The properties of the decelerator have been completely characterized in a series of experiments in which (i) the initial longitudinal velocities of the decelerated atoms (ii) the maximum magnetic field strength, and (iii) the duration of zero-field intervals between successive field pulses in neighboring deceleration stages were systematically varied. Experiments using Ar and Kr as carrier gases have clearly revealed that the H atoms are located at the surface of the jet expansion cone in each case. Comparison of the results of these experimentsmore » with numerical simulations of the atom trajectories through the decelerator provides a full description of the phase-space distribution of the decelerated atoms. Evidence is presented of transverse guiding of the beam and of a partial redistribution of the H atom population among the M{sub F} components of the F=1 manifold at times when the magnetic field strength approaches zero.« less
  • The phase stability of a multistage Zeeman decelerator is analyzed by numerical particle-trajectory simulations and experimental measurements. A one-dimensional model of the phase stability in multistage Stark deceleration [Bethlem et al., Phys. Rev. Lett. 84, 5744 (2000)] has been adapted to multistage Zeeman deceleration and compared with one- and three-dimensional particle-trajectory simulations, including the analysis of the effect of finite switch-on and -off times of the deceleration pulses. The comparison reveals that transverse effects in the decelerator lead to a considerable reduction of the phase-space acceptance at low values of the phase angle and an enhancement at high values. Themore » optimal combinations of phase angles and currents with which a preset amount of kinetic energy can be removed from atoms and molecules in a pulsed supersonic beam using a multistage decelerator are determined by simulation. Quantitative analysis of the phase-space acceptance within a given volume reveals that for our decelerator (8 {mu}s switch-off time) optimal conditions are achieved for values of the phase angle between 45 deg. and 55 deg. This conclusion is examined and confirmed by experimental measurements using deuterium atoms. Alternative approaches to generate optimal deceleration pulse sequences, such as the implementation of evolutionary algorithms or the use of higher-order modes of the decelerator, are discussed.« less