XRF Core Scanning Facility
Located at the IODP Gulf Coast Repository
at Texas A&M University
Welcome to the home page for the XRF Core Scanning lab at IODP! This site is designed to provide you with all the information you need to get acquainted with the lab, get started using the instruments, and get familiar with how to process and interpret the data. Please continue reading below, and once you're ready, feel free to start exploring the rest of the content. If you're never been to the lab, or it's been quite a while, I recommend that you start with the visitor's guide.
About the Lab
The XRF Core Scanner Lab at IODP is part of the Gulf Coast Repository (GCR), located on the campus of Texas A&M University. The lab has been in operation since late 2008, when the first core scanner arrived.
Currently, the lab houses two Avaatech XRF Core Scanners (Figures 1 & 2). The scanners can accommodate split section halves, discrete samples (loaded into holders), rock slabs, and many other forms of material if the instruments are configured properly. The only requirements for good sample analyses are: (1) the material surface must be relatively flat, (2) the material must be able to fit inside the machine (there are height, width, and length limits), and (3) the material must be able to be held firmly in place during the analyses. If you wish to analyze materials other than standard core section-halves, please contact us to determine whether we can configure the instrument accordingly.
In addition to the two core scanners, the lab houses a section-half image logger (SHIL) for collecting high-resolution, section-length images and RGB profiles (Figure 2).
Figure 1: Image showing the original Avaatech core scanner against the wall, behind the core preparation tables
Figure 2: Image showing the newer Avaatech core scanner (left, against the wall) next to the section-half imaging track (right, against the wall)
The XRF Core Scanners are each capable of generating up to 50 kVp of accelerating voltage and up to 2 mA of current. In theory, we can measure any element that has an absorption edge (K or L shell) less than 50 keV. In practice, we can't measure elements lighter than Mg (Z=12) due to strong material absorption, and we can only measure elements heavier than Ce (Z=58) if they are present in very high concentrations (so we can observe L-lines).
Many other elements are difficult to detect due to strong peak interference. Chlorine, for example, is difficult to measure using our instruments because the Cl K-peak significantly overlaps with the Rh L-peaks. Other elements are difficult to measure due to overlaps with characteristic peaks of more abundant elements and overlaps with spectral artifacts. If you're interested in measuring specific elements, please talk to the Lab Manger.
Also, please visit our full analytical capabilities page to learn more about the elements that we can measure, the excitation conditions that we can use, and the time required for the analyses.
If you're interested in scheduling time on one or both of the XRF Core Scanners, please contact the Lab Manager. The machines are heavily utilized for both Expedition-related measurements and personal scientific measurements. Due to the strong demand, you will typically need to reserve time several months in advance.
The hourly rate for all users (per XRF instrument), both internal and external, is $40. This cost covers consumables, instrument wear and tear, and basic staff support. Users are expected to do sample preparation and scanning themselves. The GCR does not currently offer scanning as a service. There is no charge to use the section-half image logger (SHIL).
Next, I recommend you check out some of our basic lab usage guides, such as the quick start guide, the data processing guide, and the film change guide. You'll likely want to refer to these guides periodically during the initial part of your visit (and they'll be available in hard-copy), but by reading through them in advance, you can familiarize yourself with some of the software and workflows that you'll encounter.
For those who have used the instruments before, and perhaps consider themselves super-users, we have some advanced usage guides. These guides cover:
Finally, we've included material dedicated to helping you better understand your data. This is arguably one of the most important topics for users of the XRF Scanners, and it is an expansive, highly technical subject. We'll talk a bit about: