J. Lidberg

A technique for lifetime measurements of long-lived atomic states utilising laser excitation of stored ion beams

Abstract A laser probing technique for atomic lifetime measurements of metastable states using an ion storage ring is presented. The method benefits from the high spectral resolution of conventional fast ion beam laser spectroscopy, and is applicable to metastable systems in lowly charged ions with lifetimes in the 10 ms–1 s regime. Due to strong probing mechanisms, the technique can be applied to ion beams with low metastable fractions. A comprehensive description of the laser probing technique is given, with examples from recent experiments on singly charged calcium, strontium and xenon, and future prospects are discussed.

Lifetimes of the metastable and levels in measured by laser probing of a stored ion beam

A laser probing method has been used in an ion storage ring to measure the lifetimes of the metastable and levels in . The lifetimes obtained were s for and s for . The most accurate results from ion trap measurements differ by 10% from each other. Our value for supports the longer lifetime value reported from Werths group. For the level, the new measurement is consistent with previous results.

Rotational-temperature evolution of a N2+ ion beam in a storage ring probed by laser induced fluorescence spectroscopy

Laser induced fluorescence spectroscopy has been applied for the first time on a stored fast molecular ion beam. The rotational temperature of the N2+ ion beam was studied as a function of storage time. For up to 1 s of storage time, a temperature of 1040 K can be used to describe the rotational energy distribution.

Laser probing of ions in a storage ring: A method for selective determination of lifetimes of metastable states

A collinear laser probing technique is introduced for use in ion storage rings. This method can be used for high resolution studies of the decay properties of metastable states in ions. An experiment on singly charged xenon utilizing this technique is presented. By selective excitation of individual hyperfine states a drastic hyperfine induced quenching was observed. Systematic effects from ion beam neutralization in the rest gas and mixing effects occurring in the bending magnets are discussed.

Hyperfine structure measurements in Kr II

The fast ion beam laser technique has been utilized to study the hyperfine structure in the transitions 4d4D7/2-5p4D72/0 at 6420 Å and 4d4D7/2-5p4D52/0 at 6303 Å in singly-charged krypton. The magnetic dipole and electric quadrupole hyperfine constants have been extracted for the upper levels of the transitions.

Hyperfine structure and lifetimes of metastable states studied by means of laser excitation of stored ions

Studies of hyperfine structure of metastable states are facilitated by storage rings and ion traps. Here we report on the development of a method to study metastable states of stored singly charged ions by laser excitation. The experiments were performed at the accelerator and storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm. We discuss means to improve the resolution and the possibility to extend the method to highly charged ions.