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Again, please note that it will be necessary to cover the core surface with Ultralene® film and GLAD® Plastic Wrap in order to protect the nose of the instrument and the underside of the shield from contamination. See Preparing Section Halves, below.
Important! Do not measure the core section half without covering it with film! Exception might be hard rock core section (see Preparing Section Halves below).

Sample Preparation

Sample preparation is split into two main categories: discrete samples and section halves.

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1. Locate the area on the section half to be measured. Make If measuring sediment, make sure that section portion has a layer of Ultralene® film on it. Put a layer of GLAD® wrap on the rest of the core that the lead shield might touch. We do not want to contaminate the core or pXRF. If hard rock, make sure that the section is dry and perfectly cleaned before measuring (a Ultralene® film may not be necessary).
2. Place the shield over the core so the point of measurement is centered. Use the plexiglass view-finder to help find this spot.
3. Take note of the measurement position on the core using the ruler. Lower the pXRF into the shielding oriented so the two indents on the analyzer are on the same side as the tightening screws.
4. Tighten the screws until it feels firm. This locks the pXRF into place and helps stabilize it. Keep a hand on the handle while measuring to ensure it does not fall.

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The pXRF has a feature to apply linear regressions for elements, quantifying data as it is measured. It is NOT recommended for use. Data Quantification should be done outside of the software by the scientists. Please note that this feature can provide erratic results and not detect elements that are present.

All data from the handheld pXRF should be considered qualitative (like the big XRF Core Scanners back on shore at the GCR) unless the scientists do the HUGE amount of work to measure representative materials, a representative sample of the samples (see Note 2 below), adjust for differentials in moisture content, etc. In other words, the standards are powders mounted in the XRF cups, while the section halves or TSBs are not in that form. The XRF data get from each of those (powder mounts, section halves, and TSB) are all going to be different and have different concentration-to-count ratios.

Note 1: we prefer uploading the data without any correction factors (slope, intercept) included because there’s no easy way to export that information from the gun and then upload and/or qualify the LIMS data with those factors. This especially applies to section halves and/or discrete samples (e.g., CUBE or TSB samples). See Note 3 below about powdered samples and powder mounts.

Note 2: grain size/spot size is a big issue for the pXRF because the spot size is 8 mm (or 10 mm) for our gun.

Note 3: If you take the time to create powders so that the samples and standards are in the same form factor and are prepared the same way, then you can run the standards, determine the slope/intercept values to correct the inherent instrument calibration to your sample set, enter those into the gun software, and then produce quantitative data from the powder samples. This requires a good hand at creating the XRF cups so they’re (a) consistently full (you want at least 1 cm of powder to be “infinite” depth for the X-rays), (b) consistently made, and (c) don’t have air gaps. Once you have the cups filled, you measure them using the test stand (samples upside down on the instrument nose and inside the shielded cover) and you can get quantified data.
Note 3 *only* works when you’re comparing like to like. You should *not* attempt to use powdered standards to quantify non-powdered samples.

Troubleshooting

Indicator Bar shows a 'CommError'

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