Time-of-flight mass spectrometry of mineral volatilization: Toward direct composition analysis of shocked mineral vapor

Abstract

An integrated ion trap and time-of-flight mass spectrometer for chemical and photo-reaction dynamics studies Rev. Sci. Instrum. 83, 043103 (2012) Laser induced and controlled chemical reaction of carbon monoxide and hydrogen J. Chem. Phys. 135, 204303 (2011) Excitonic parameters of GaN studied by time-of-flight spectroscopy Appl. Phys. Lett. 99, 101108 (2011) An LIF characterization of supersonic BO (X2Σ+) and CN (X2Σ+) radical sources for crossed beam studies Rev. Sci. Instrum. 82, 083107 (2011) Additional information on Rev. Sci. Instrum. We have developed an orthogonal-acceleration time-of-flight mass spectrometer to study the volatiles produced when a mineral's shock-compressed state is isentropically released, as occurs when a shock wave, driven into the mineral by an impact, reflects upon reaching a free surface. The instrument is designed to use a gun or explosive-launched projectile as the source of the shock wave, impact onto a flange separating a poor vacuum and the high vacuum (10 −7 Torr) interior of the mass spectrometer, and transmission of the shock wave through the flange to a mineral sample mounted on the highvacuum side of the flange. The device extracts and analyzes the neutrals and ions produced from the shocked mineral prior to the possible occurrence of collateral instrument damage from the shockinducing impact. The instrument has been tested using laser ablation of various mineral surfaces, and the resulting spectra are presented. Mass spectra are compared with theoretical distributions of molecular species, and with expected distributions from laser desorption.