Generation and Application of Ultra-High-Intensity Magnetic Field Gradient Pulses for NMR Spectroscopy
✍ Scribed by Petrik Galvosas; Frank Stallmach; Günter Seiffert; Jörg Kärger; Udo Kaess; Günter Majer
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 131 KB
- Volume
- 151
- Category
- Article
- ISSN
- 1090-7807
No coin nor oath required. For personal study only.
✦ Synopsis
Two different concepts of gradient current power supplies are introduced, which are suitable for the generation of ultra-high intensity pulsed magnetic field gradients of alternating polarity. The first system consists of a directly binary coded current source (DBCCS). It yields current pulses of up to ±120 A and a maximum voltage across the gradient coil of ±400 V. The second system consists of two TECHRON 8606 power supplies in push-pull configuration (PSPPC). It yields current pulses of up to ±100 A and a maximum voltage across the gradient coil of ±300 V. In combination with actively shielded anti-Helmholtz gradient coils, both systems are used routinely in NMR diffusion studies with unipolar pulsed field gradients of up to 35 T/m. Until now, alternating pulsed field gradient experiments were successfully performed with gradient intensities of up to ±25 T/m (DBCCS) and ±35 T/m (PSPPC), respectively. Based on the observation of the NMR spin echo in the presence of a small read gradient, procedures to test the stability and the matching of such ultra-high pulsed field gradient intensities as well as an automated routine for the compensation of possible mismatches are introduced. The results of these procedures are reported for the PSPPC system.