VARIABLE TEMPERATURE DATA

VT DATA FROM PHOENIXNMR PROBE AND MODULES UTILIZING ²⁰⁷PB NMR SIGNAL

These data were all acquired at 14.1 T, using a single PhoenixNMR HXY probe body and merely exchanging different probe heads, using the ²⁰⁷Pb NMR signal from lead nitrate. See Experimental Details, below.

The HXY Premium Probe is typically quoted with a VT range of -125°C to +125°C. The standard VT range for the HX Probe is -75°C to +100°C. However, module identity and probe materials can affect the final specified VT range for a given probe.

Request a quote to obtain more detailed VT information for a specific probe configuration.

VT DATA BY MODULE AND SPEED

• 1.2mm   1.6mm   3.2mm   4mm
• Temperature vs Spinning Speed
• Static

1.2 MM SPINNING MODULE

Temperature Gradients across the Sample, 1.6 mm module, Set Point = -125^oC to +125^oC, VT flow = 25 lpm, MASS = 10-40 kHz

1.6 MM SPINNING MODULE

Sample Temperature vs. Set Point, 1.6 mm module, Set Point = -125^oC to +125^oC, VT flow = 25 lpm, MASS = 10-40 kHz

3.2 MM SPINNING MODULE

Temperature Gradients across the Sample, 3.2 mm module, Set Point = -125^oC to +125^oC, VT flow = 30 lpm, MASS = 4-25 kHz

4 MM SPINNING MODULE

Temperature Gradients across the Sample, 4 mm module, Set Point = -125^oC to +125^oC, VT flow = 35 lpm, MASS = 3.5-18 kHz

TEMPERATURE VS. SPINNING SPEED FOR VARIOUS MODULES

Temperature increases in a sample due to frictional heating from spinning. This data compares the amount of heating for different rotor sizes spinning at 25^oC. Note the speeds are normalized to show zero to maximum spinning speed for each of the rotor sizes.VT flow rate is optimized for each rotor size (15 lpm for 1.2 mm, 25 lpm for 1.6 mm, 30 lpm for 3.2 mm, and 35 lpm for 4 mm rotor).

STATIC MODULE

EXPERIMENTAL DETAILS AND DATA ANALYSIS:

• ²⁰⁷Pb MAS NMR signals were converted to temperature measurements using the method detailed in A. Bielecki and D.P. Burum, JMR A 116, 2015-2020 (1995), with the exception that, for these data, the lead nitrate sample filled the entire specified sample volume of a given coil for all measurements.
• Warning: if you try this at home, do not spin a full rotor of PbNO₃ at the maximum spinning speed for the module due to the high density of the sample.
• ²⁰⁷Pb static NMR signals were converted to temperature measurements using the method detailed in P. A. Beckman and C. Dybowski, JMR 146, 379-380 (2000). The lead nitrate sample filled the entire specified sample volume of the 5mm static coil.
• For a given set of experimental conditions, the sample temperature data and temperature gradient data were acquired from the same NMR spectrum.
• Initial temperature calibration for a given module was performed by recording a ²⁰⁷Pb spectrum at set point = 25^oC at the minimum spinning speed reported for a given module (or static for the static module), and assigning the chemical shift of the PbNO₃ resonance to 25^oC under those conditions. All other temperature data for a given module are referenced to this starting condition.
• “Temperature gradient” is calculated from the width at baseline noise of the full ²⁰⁷Pb lineshape acquired for a given temperature/MASS.
• “Sample temperature” is calculated from the position of the weighted center of the full ²⁰⁷Pb lineshape.
• “Set temperature” is the temperature monitored at the dewar outlet where VT gasses enter the module.
• VT flow rates for each module are the flow rates recommended by PhoenixNMR for optimal VT performance while also spinning at high speed.
• Contact Us for more information about performing VT using a PhoenixNMR probe.