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PFG/Diffusion Z Gradient Coils and Probes-

Pulsed Field Gradient Coils up to 4,000 G/cm (40 T/m)

Highest Efficiency, Ultra-Shielded, Fastest Switching

Which gradient coil is preferred for most NB applications? The 20-40C allows a longer sample region than the 16-38 and shims a little better, so it permits higher S/N but requires a larger gradient amplifier. Both coils are widely used.

 

Parameter

Model

16-38

Model

20-40 C

Model

47-70

Units

Outside diameter

38

39

70

mm

Diameter of rf shield

16

20

50

mm

Clear I.D.

14

17.5

47

mm

Cooling method

Water

Water

Water

-

Continuous gradient (G/cm)

380

180

75

G/cm

Continuous gradient (T/m)

3.8

1.8

0.75

T/m

Pulse gradient

3800

1100

480

G/cm

Duty cycle
1%
2.5%
2.5%

Gradient gain, α

480

180

30

mT/A/m

Continuous current (water)

8

10

25

A

Peak current

80

60

160

A

di for 4% local deviation

6

12

24

mm

zi for 4% local deviation

13

28

30

mm

DC resistance, RE

1.6

1.5

0.7

Ω

Inductance, L

130

200

170

μH

Slew rate, αV / L , at 1 V

3700

900

180

T/m/s

Local deviation (or differential linearity) is defined as the rms deviation from the mean gradient over the specified diameter, di, and length, zi, of the cylindrical sample region.  Eddy currents from the internal RF shield are negligible.  The gradient slew rate GS is the instantaneous rate of change in gradient when a 1 V step is applied.  The continuous current ratings are true continuous ratings for a single axis with no time limit and adequate cooling.

Doty Diffusion probe used to perform Oscillating Gradient Spin Echo (OGSE)

Results obtained with a Doty 300 MHz diffusion probe with a model 16-38 Z gradient

We wish to thank Junzhong Xu and Prof. John Gore at Vanderbilt Univ., Nashville, TN, for sharing their NMR results.
 (For more information on this work click here.)

Figure 1. Experimental (markers) and fitted (lines) signal attenuation as a function of diffusion gradient amplitudes and frequencies

Figure 2. Signal attenuation obtained by PGSE measurements of two synchronized cell samples with b values up to 10,000s/mm2

Figure 3. Dispersion curves (ADC vs f) of two types of synchronized cells. Error bars show standard deviations of all six samples.

 

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