Variable Temperature (VT) Operation on NMR500

Note: Only trained and authourized users are allowed to conduct VT experiments.

NMR500 is equipped with a FTS temperature control unit and cooler with air supplied through a new Parker/Balston air dryer and pressure regulating tank. The FTS controller sits in the back corner of the room facing the 500 magnet. The FTS should be left on at all times. Do not turn it off unless instructed to do so. Each power-off of the system requires a new 20 mins or longer pull-down of the system to -80C and back up to the set temperature.


The FTS system sends dry, temperature-regulated air (26C)  into the probe so that the sample temperature is ~23C. This setup is a compromise between temperature stability and ease of use for routine work. For temperature ranging from ~ -70C to 90C, the FTS is sufficient for routine VT experiments.

Although the procedure is simple, you are strongly advised to notify me of your plan the first time you do an VT experiment. Please e-mail me with your plan, including time, temperature range and experiments to do. Once you are trained to use the system, you can do the VT experiments in the future by yourself.

Note, the displayed temperature at FTS and in vnmrJ may differ from the actual sample temperature. A few degrees offset is quite normal once the target temperature is 20, 30C off room temperature. If accurate temperature setting is needed, you should calibrate it with an ethylene glycol (for temperature above ambient) or methanol (for low temperature) sample. Please talk to staff for detailed procedure doing this.


Sample Holder/Spinner:

When performing VT experiments, closely watch VT display and FTS set temperature and observe all dangerous signs and alarms.

H. Zhou updated Aug 2011