Towards optimal noise properties of NMR antenna-receiver chain

Kolar, Petar; Hrabar, Silvio; Grbić, Mihael Srđan

doi:10.23919/eucap.2017.7928829

Cited by 1 publication

(1 citation statement)

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“…From earlier discussions and (14), it is apparent that the cable at the beginning of the receiving chain (between the NMR probe and duplexer) should be as short as possible. If the cryostat and spectrometer are necessarily distant from each other, and long cables are required to connect them, then it is imperative to use the shortest and the least noisy cable (i.e., the cable with the lowest losses) between the NMR probe and duplexer [22]. In this way, the noise properties of elements after the pre-amplifier are efficiently suppressed, while those of the pre-amplifier and elements before are negligible.…”

Section: Improvement Suggestionsmentioning

confidence: 99%

Sensitivity Enhancement of NMR Spectroscopy Receiving Chain Used in Condensed Matter Physics

Kolar

Grbić

Hrabar

2019

Sensors

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Assurance of high measuring sensitivity is one of the most challenging issues for any nuclear magnetic resonance (NMR) spectroscopy system. To this end, we propose an accurate noise model of the entire probe-to-spectrometer receiving chain for condensed matter physics, based on the concept of noise figure. The model predicts the propagation of both the signal and noise levels in every component of the NMR spectroscopy receiving chain. Furthermore, it enables identification of the "weakest" component and, therefore, the optimization of the whole system. The most important property of the proposed model is the possibility to find system parameters that reduce the measurement time by an a priori calculation, rather than an a posteriori approach. The model was tested experimentally on several different samples. It was found that the measurement time can still be significantly shortened, down to at least one half of the measurement time, starting from optimized conditions with commercially available components. Thus, the proposed model can be used as a tool for both quantitative analysis of the noise properties and a sensitivity prediction of practical NMR systems in physics and material science.

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Section: Improvement Suggestionsmentioning

confidence: 99%