2.1 Probe Description
 

The HR-MAS probes have been designed to perform solution type experiments, while spinning the sample at the magic angle. The probes are either doubly tuned (e.g. 1 H and 13 C) or triply tuned (e.g. 1 H, 13 C and 15 N), in addition to a 2 H lock channel. All three (or four) channels are operating via a single NMR transmit/receive solenoid coil located inside the MAS turbine (see figure 2.1). The probes are capable of performing either direct or indirect (inverse) detection experiments.

Properties of the HR-MAS probes include:

1. MAS at spinning rates of up to 16 kHz for 4 mm o.d. Zirconia rotors for liquid or

liquid-like samples and up to 6 kHz with spherical volume PTFE or Kel-F in-serts;

2. Sample insertion/ejection without removal of the probe (up to 600 MHz);

3. Magic angle adjustment with micrometer screw at probe bottom;

4. Built-in heater/dewar and thermocouple for VT operation from -20°C to +70°C;

5. Optical spin rate counter with trigger signal output for rotor synchronized ex-periments;

6. Automatic insert and eject of the sample using the MAS sample changer.

Figure 2.1. Upper probe chamber with MAS stator in magic angle position.