A new atomic beam source for use in laser-based experiments is described and characterized. The physically collimated source which has been tested using calcium, produces an atomic beam with low angular divergence and narrow transverse Doppler profile, as measured using fluorescence techniques with a near resonant laser beam. The low angular divergence of the source is essential for new experiments which study super-elastic scattering of electrons from laser prepared targets within a magnetic field, since the atomic beam must pass through a narrow gap between the coil windings. The beam density for calcium is calculated to be 2.8 × 109 atoms cm-3 when the source is operated at a temperature of 1090 K. This is sufficient to produce good electron energy loss and super-elastic scattering signals, while ensuring negligible radiation trapping within the atomic beam. © 2006 IOP Publishing Ltd.A new atomic beam source for use in laser-based experiments is described and characterized. The physically collimated source which has been tested using calcium, produces an atomic beam with low angular divergence and narrow transverse Doppler profile, as measured using fluorescence techniques with a near resonant laser beam. The low angular divergence of the source is essential for new experiments which study super-elastic scattering of electrons from laser prepared targets within a magnetic field, since the atomic beam must pass through a narrow gap between the coil windings. The beam density for calcium is calculated to be 2.8 × 109 atoms cm-3 when the source is operated at a temperature of 1090 K. This is sufficient to produce good electron energy loss and super-elastic scattering signals, while ensuring negligible radiation trapping within the atomic beam. © 2006 IOP Publishing Ltd.

Measurement Science and TechnologyOct 19, 200616 citations

Selective detection of metastable helium atoms by elastic scattering collisions

Kosuke Kato, D. W. Fitzakerley, M. C. George +5 more

A method for efficient and selective detection of $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ and $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ metastable He atoms is presented. Elastic collisions with Ar atoms in a diffuse gas spatially separate these $2S$ atoms from the copropagating UV photons that are inherently present in metastable beams. The deflected $2S$ atoms are detected on a large-solid-angle Faraday cup. A He discharge lamp can selectively quench $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ atoms, and optical pumping together with a Stern-Gerlach magnet can selectively remove $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms. As a result, we are able to efficiently detect either $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ or $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms (or both) without a UV background.A method for efficient and selective detection of $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ and $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ metastable He atoms is presented. Elastic collisions with Ar atoms in a diffuse gas spatially separate these $2S$ atoms from the copropagating UV photons that are inherently present in metastable beams. The deflected $2S$ atoms are detected on a large-solid-angle Faraday cup. A He discharge lamp can selectively quench $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ atoms, and optical pumping together with a Stern-Gerlach magnet can selectively remove $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms. As a result, we are able to efficiently detect either $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ or $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms (or both) without a UV background.

Physical Review AJul 25, 20122 citations

A method for efficient and selective detection of

2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S

and

2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S

metastable He atoms is presented. Elastic collisions with Ar atoms in a diffuse gas spatially separate these

2S

atoms from the copropagating UV photons that are inherently present in metastable beams. The deflected

2S

atoms are detected on a large-solid-angle Faraday cup. A He discharge lamp can selectively quench

2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S

atoms, and optical pumping together with a Stern-Gerlach magnet can selectively remove

2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S

atoms. As a result, we are able to efficiently detect either

2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S

2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S

atoms (or both) without a UV background.