Nu Instruments | Low Backgrounds with Noblesse
This application note explains how new source materials and cleaning methods reduce mass 36 background in Noblesse. It focuses on H³⁵Cl interference and its importance for ⁴⁰Ar/³⁹Ar dating and small-sample measurement.
Mass 36 background is important in ⁴⁰Ar/³⁹Ar dating because ³⁶Ar is used to correct for atmospheric contamination. The note explains that the mass 36 peak may include ³⁶Ar, H³⁵Cl and C₃, with C₃ easily resolved by Noblesse.
Following developments in source materials and cleaning methods, Noblesse achieved very low mass 36 backgrounds. The note reports H³⁵Cl interference as low as 2 x 10⁻¹⁵ ccSTP, measured both while pumping and in static mode with Ar present.
For small samples, this level of H³⁵Cl interference is similar to the uncertainty in the ³⁶Ar measurement. For larger samples, it is expected to be lost in the measurement noise, supporting practical lower-resolution operation in many cases.
Key Takeaways:
- New materials and cleaning methods reduce mass 36 background.
- H³⁵Cl interference can be as low as 2 x 10⁻¹⁵ ccSTP.
- Low backgrounds support accurate ³⁶Ar correction in Ar dating.
Related Articles
