RIMSKI – Resonance Ionization Mass Spectrometer for Krypton Isotopes – is a newly developed ultra sensitive instrument with a cryogenic sample concentrator and a laser ion source designed for isotopic analysis of extraterrestrial material. Laser heating is used for extraction of krypton from samples into the mass spectrometer volume. Atoms continuously condense on a cold spot in the ion source, and are repeatedly released by laser heating. They are ionized in the evaporation plume using three tunable dye lasers and one frequency tripled Q-switched Nd:YAG laser. Two resonant transitions are employed (at 116.5 nm, produced by four-wave frequency mixing in Xe, and 558.1 nm) and are followed by single photon ionization at 1064 nm. Multiple analyses of air aliquots and <5 mg samples of meteorites, both containing ∼106 total krypton atoms, show precision ∼1% for major isotope ratios. They are reproducible to this level through a day's analyses, allowing calibration for linear and non-linear mass discrimination by sample-standard bracketing. Cosmogenic 81Kr can be reliably detected at the few thousand atom level, corresponding to determination of cosmic ray exposure (CRE) ages from meteorite samples of a few milligrams. Measured CRE ages of noncumulate eucrites are: Pasamonte, 7.9 ± 1.3 My; Sioux County, 20.9 ± 4.0 My; Bereba, 23.7 ± 2.6 My; Stannern, 33.3 ± 2.5 My. These are in good agreement with literature values.

Tunable coherent VUV radiation from 115.8 to 116.9 nm has been produced by non-linear four-wave sum frequency mixing in a xenon–argon mixture. 116.5 nm light generated by this means has been used as the first step in a three color, doubly resonant ionization scheme for Kr. In the process of validating the system the xenon refractive index per atom (STP) at 116.5 nm has been determined to be (n(Xe) − 1)/NXe = −6.8(±0.8) × 10−23 cm3.

RIMSKI – Resonance Ionization Mass Spectrometer for Krypton Isotopes – is a newly developed ultra sensitive instrument with a cryogenic sample concentrator and a laser ion source designed for isotopic analysis of extraterrestrial material. Laser heating is used for extraction of krypton from samples into the mass spectrometer volume. Atoms continuously condense on a cold spot in the ion source, and are repeatedly released by laser heating. They are ionized in the evaporation plume using three tunable dye lasers and one frequency tripled Q-switched Nd:YAG laser. Two resonant transitions are employed (at 116.5 nm, produced by four-wave frequency mixing in Xe, and 558.1 nm) and are followed by single photon ionization at 1064 nm. Multiple analyses of air aliquots and <5 mg samples of meteorites, both containing ∼106 total krypton atoms, show precision ∼1% for major isotope ratios. They are reproducible to this level through a day's analyses, allowing calibration for linear and non-linear mass discrimination by sample-standard bracketing. Cosmogenic 81Kr can be reliably detected at the few thousand atom level, corresponding to determination of cosmic ray exposure (CRE) ages from meteorite samples of a few milligrams. Measured CRE ages of noncumulate eucrites are: Pasamonte, 7.9 ± 1.3 My; Sioux County, 20.9 ± 4.0 My; Bereba, 23.7 ± 2.6 My; Stannern, 33.3 ± 2.5 My. These are in good agreement with literature values.