Sample Environment of the SNAP Instrument
Sample size and maximum pressure are coupled parameters and dictate both the type of pressure device that is most appropriate and limits the type and amount of information that can be extracted from the data. Additionally, varying temperature conditions, hot or cold, affects the pressure limits of each type of pressure device in our suite. For example, our devices that can reach 10 GPa at room temperature can only reach 6 GPa at 1000 K. The instrument staff welcomes any technical questions about the feasibility of your experimental ideas.
SNAP Pressure Equipment
| Equipment | Max. Pressure (GPa) | Temperature range (K) | Sample size (mm³) | d-spacing range (Å) | Scattering angles (°) | Notes |
| Paris-Edinburgh press, single-toroidal anvils | 10 | 85-350 | <87 | 0.7-7 Å | 26-142° 2Θ, +/- 7° vertical | |
| Paris-Edinburgh press, double-toroidal anvils | 20 | 85-350 | <31 | 0.7-7 Å | 26-142° 2Θ, +/- 7° vertical | parasitic Bragg peaks from polycrystalline diamond anvils |
| Paris-Edinburgh press, graphite heater | 6 | 300-1500 | <68 | 0.7-3 Å | 83-97° 2Θ, +/-22° vertical | parasitic Bragg peaks from heater assembly | Clamp Cell | 2 | 10-350 | <150 | 0.7-15 Å | 26-142° 2Θ, +/- 22° vertical | collimation greatly reduces parasitic scatter from cell (NiCrAl), but may still see cell peaks at low 2Θ |
| Gas cell (aluminum) | 0.6 | 10-350 | <700 | 0.7-15 Å | 26-142° 2Θ, +/- 22° vertical | collimation greatly reduces parasitic scatter from cell (Al), but may still see cell peaks at low 2Θ |
| Gas cell (TiZr null-scattering alloy) | 0.2 | 10-350 | <340 | 0.7-15 Å | 26-142° 2Θ, +/- 22° vertical | collimation greatly reduces parasitic scatter from cell, no Bragg peaks from null-scattering alloy |
| Diamond anvil cell | 40 | 10-350 | <0.05 | 0.7-3 Å | 80-100° 2Θ, +/- 22° vertical | In development (must contact staff prior to planning); Very small sample signal, difficult attenuation corrections may produce ambiguious result; Can only run strongly scattering samples of high crystal symmetry |
Sample Mass Calculator
Sample Geometry
| Click below for illustration of sample shapes for use in the Paris-Edinburgh press | Volume (mm3) |
| Double-toroid, encapsulated | 16.8 |
| Double-toroid, non-encapsulated | 31.1 |
| Single-toroid, encapsulated | 55.5 |
| Single-toroid, non-encapsulated | 87.1 |
| Graphite furnace | 68.1 |
If you see NaN in the "Sample Mass Needed (mg)" field, then one of your entries probably contains non-numeric data or is not a valid number, for example, entering 3.9.0 (double decimal points).
