التفاصيل البيبلوغرافية
| العنوان: |
A more accurate tuning-matching technique for NMR probes using wobulation and variable phase shifter |
| المؤلفون: |
Hervé Desvaux, Gaspard Huber, Michel Luong, Guillaume Ferrand |
| المصدر: |
Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering. 45:59-68 |
| بيانات النشر: |
Wiley, 2015. |
| سنة النشر: |
2015 |
| مصطلحات موضوعية: |
Physics, Radiological and Ultrasound Technology, Acoustics, Network analyzer (electrical), RF probe, Power (physics), law.invention, Capacitor, Radiation damping, law, Electronic engineering, Power dividers and directional couplers, Radiology, Nuclear Medicine and imaging, Sensitivity (control systems), Physical and Theoretical Chemistry, Phase shift module, Spectroscopy |
| الوصف: |
For optimizing sensitivity and RF excitation, high resolution NMR probes have to be tuned at the Larmor frequency and matched to 50 Ω-transmission lines to which they are connected. For achieving this setting, one usually resorts to the wobulation function which consists in sweeping the frequency of the power source while monitoring and minimizing the reflected power taken from a directional coupler through adjusting the tuning and matching capacitors. However, the presence of a transmission-reception switch between the directional coupler and the probe leads to the appearance of extra loss and reactance, and affects the determined values of the previous mentioned capacitors. Even if this situation is usually satisfactory, the true tuning-matching condition is required for optimal NMR sensitivity and for reliable spectra analyses when nonlinear effects are present (radiation damping, spin-noise experiments, etc.). To circumvent the need of network analyzer directly attached to the probe for finding this optimal tuning-matching condition, in the current work, we report a procedure which combines wobulation and choice of a transmission-line phase shift obtained by a variable phase shifter inserted between the probe and the switch. The technique was successfully validated with help of a network analyzer. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 45B: 59–68, 2015 |
| تدمد: |
1552-5031 |
| URL الوصول: |
https://explore.openaire.eu/search/publication?articleId=doi_________::4000969b72998b5f88bdfaff5ad1ee8e
https://doi.org/10.1002/cmr.b.21277 |
| حقوق: |
OPEN |
| رقم الأكسشن: |
edsair.doi...........4000969b72998b5f88bdfaff5ad1ee8e |
| قاعدة البيانات: |
OpenAIRE |
