| 摘要 |
An apparatus for DNP-NMR measurement on a sample (P), with a magnet configuration (M) for producing a magnetic field in a first working volume (V1), wherein the magnet configuration (M) produces a stray field in a second working volume (V2) in the direction of an axis (z) with a magnetic field gradient (H1M, H2M, HnM) in the direction of the axis (z), wherein the axis (z) extends through the second working volume (V2), with a device (N) for measuring MR signals, with a DNP excitation device (D), and with a positioning mechanism (T) for transferring the sample (P), is characterized in that, near the second working volume (V2), a compensation configuration (m) made of magnetic material is mounted that, in the operating condition of the magnet configuration (M), produces a magnetic field gradient (H1m, H2m, Hnm) in the direction of the axis (z) in the second working volume (V2) that is between−90% and−110% of the magnetic field gradient of the same order (H1M, H2M, . . . ; HnM) of the stray field of the magnet configuration (M) in the direction of the axis (z) in the second working volume (V2). Thus, homogenization of the magnetic field in the second working volume can be achieved by technically simple means.
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