Improvement in the Analytical Capabilities of LA-ICP-MS for High Spatial Resolution U-Pb Dating of Zircon Using Mixed-Gas Plasma

Table 1

Summary of the operating parameters used for LA-ICP-MS.

GeoLas 2005 laser ablation system
Wavelength	ArF 193 nm
Pulse length	15 ns
Energy density	6–8 J·cm^−2
Spot size	10, 16, 24, 32 μm
Repetition rate	3 Hz
Ablation cell gas	Helium (0.5 l·min^−1)
Makeup gas	Argon (0.631 l·min^−1 in dry plasma, 0.72 l·min^−1 in 2% ethanol plasma)
Ablation mode	Single spot
Agilent 7500a ICP-MS
RF forward power	1380 W
Plasma gas flow rate	14.0 l·min^−1
Auxiliary gas flow rate	1.0 l·min^−1
Argon gas flow rate	0.2 l·min^−1
Aqueous solution uptake rate	0.33 ml·min^−1 at 0.1 RPS
Skimmer cone	0.4 mm Ni
Sampling cone	1 mm Ni
Ion optical settings	Typical
Dwell time per isotope	6 ms
Detector mode	Dual
Shield torch system	ON
Plasma conditions	Dry plasma or 2% ethanol plasma