L. S. Goodman

Collinear laser and slow‐ion‐beam apparatus for high‐precision laser‐rf double‐resonance spectroscopy

A new apparatus has been constructed for high‐precision hyperfine structure measurement of atomic ions by laser‐radio‐frequency double‐resonance technique involving a slow ion beam and a laser in collinear geometry. The low ion energy (1–1.5 keV) leads to longer interaction time with the applied rf field. Consequently, extremely narrow linewidths of ∼60 kHz have been observed for the first time in such systems. The apparatus has been used for the measurement of hyperfine structure of the 4f7(8S0)5d9D02,3,4,5 metastable levels in 151Eu+ and 153Eu+. The magnetic dipole and the electric quadrupole hyperfine constants, A and B, respectively, have been determined with higher precision (2–3 orders of magnitude).

Achievement of Extremely Homogeneous Magnetic Fields

A design is given of a magnet for producing a uniform homogeneous field. The pole piece assembly consists of two Hypernom pole pieces separated by quartz spacers with a nonmagnetic gap of quartz to separate the pole assembly from the Armco iron legs. The sharpening of the atom-beam resonance in Ga/sup 72/ as a result of magnetic circuit modifications is given, comparing old pole pieces and the new pole design. (B.O.G.)

High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance☆

A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of approx.60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f/sup 7/(/sup 8/S/sup 0/)5d /sup 9/D/sub J//sup 0/ metastable levels of /sup 151,153/Eu/sup +/ has been measured with high precision. 10 refs., 8 figs.

SYSTEM FOR SUPPRESSING LARGE, NONSTATISTICAL NOISE BURSTS IN DIGITAL AVERAGING

A device which eliminates the effect of noise bursts that exceed the average signal rate of digital data by more than a chosen, preset amount has been designed, constructed, and is herein described.