Request
To perform noble gas measurements please submit a form.
This information will be used by the laboratory director to prioritize projects and schedule analyses. The lead time required to obtain 40Ar/39Ar results is primarily dictated by when the laboratory sends out shipments for neutron irradiation to the USGS TRIGA reactor. This normally occurs three times a year: January, May, and September. With typical back log within the laboratory, users can expect to analyze samples from a given irradiation in about 2-4 months after the date of irradiation with the scheduling of work set by the laboratory director. The rate limiting step in (U-Th)/He analysis is generally zircon dissolution. Zircon dissolution may be performed only by Stanford-affiliated researchers trained in the use of HF and other reagents in the the mineral dissolution facility.
User Policy
- Analysts are expected to prepare their own samples and make their own 40Ar/39Ar and/or (U-Th)/He measurements with assistance from laboratory staff.
- Sample preparation for neutron irradiation must follow laboratory guidelines to ensure compliance with the conditions of our radioactive isotope use license.
- For 40Ar/39Ar projects integral to a PhD or MS thesis, students are required to take GS 281 (Principles of 40Ar/39Ar Thermochronometry).
- Remote management of analysis sessions is possible for experienced users.
- Fees for noble gas analyses are determined using a $25/hour laboratory use rate for Stanford-affiliated researchers. If time is available, researchers from other institutions may also make noble gas measurements.
- "Per Sample" rates can be determined by multiplying the time required to perform a single heating step, grain fusion, or laser ablation pit by the number of analyses required to reach the required resolution or sampling rate. About 4 sample 40Ar/39Ar measurements and one blank determination can be made in an hour. For example, a typical sample that takes 4 hours to analyze (16 measurements) costs a Stanford-affiliated user $100.
- There is no charge for standardization measurements (e.g., flux monitors or those performed to calibrate detectors).
- Charges for (U-Th)/He work include grain dissolution and ICP-MS analysis.