Sample Environment of the SNAP Instrument

Spallation Neutrons and Pressure Diffractometer

SNAP | BL-3 | SNS

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

	Bulk Modulus (GPa)	Density (g/cm³)	Volume (mm³)	Sample Mass Needed (mg)
Custom Values
NaCl	24.4	2.17	87.1	171.888
MnO	148.0	5.37	87.1	354.256
V	160.0	6.00	87.1	388.104
CoO	180.0	6.44	87.1	402.766
Bi	31.0	9.78	87.1	767.770

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).