10 research outputs found
The Fantastic Four: A plug 'n' play set of optimal control pulses for enhancing nmr spectroscopy
We present highly robust, optimal control-based shaped pulses designed to
replace all 90{\deg} and 180{\deg} hard pulses in a given pulse sequence for
improved performance. Special attention was devoted to ensuring that the pulses
can be simply substituted in a one-to-one fashion for the original hard pulses
without any additional modification of the existing sequence. The set of four
pulses for each nucleus therefore consists of 90{\deg} and 180{\deg}
point-to-point (PP) and universal rotation (UR) pulses of identical duration.
These 1 ms pulses provide uniform performance over resonance offsets of 20 kHz
(1H) and 35 kHz (13C) and tolerate reasonably large radio frequency (RF)
inhomogeneity/miscalibration of (+/-)15% (1H) and (+/-)10% (13C), making them
especially suitable for NMR of small-to-medium-sized molecules (for which
relaxation effects during the pulse are negligible) at an accessible and widely
utilized spectrometer field strength of 600 MHz. The experimental performance
of conventional hard-pulse sequences is shown to be greatly improved by
incorporating the new pulses, each set referred to as the Fantastic Four
(Fanta4).Comment: 28 pages, 19 figure
Optimal Control Design of Excitation Pulses That Accommodate Relaxation
An optimal control algorithm for mitigating the effects of T1 and T2 relaxation during the application of long pulses is derived. The methodology is applied to obtain broadband excitation that is not only tolerant to RF inhomogeneity typical of high resolution probes, but is relatively insensitive to relaxation effects for T1 and T2 equal to the pulse length. The utility of designing pulses to produce specific phase in the final magnetization is also presented. The results regarding relaxation and optimized phase are quite general, with many potential applications beyond the specific examples presented here
Optimal Control Design of Excitation Pulses That Accommodate Relaxation
An optimal control algorithm for mitigating the effects of T1 and T2 relaxation during the application of long pulses is derived. The methodology is applied to obtain broadband excitation that is not only tolerant to RF inhomogeneity typical of high resolution probes, but is relatively insensitive to relaxation effects for T1 and T2 equal to the pulse length. The utility of designing pulses to produce specific phase in the final magnetization is also presented. The results regarding relaxation and optimized phase are quite general, with many potential applications beyond the specific examples presented here
Optimal Control Design of Excitation Pulses That Accommodate Relaxation
An optimal control algorithm for mitigating the effects of T1 and T2 relaxation during the application of long pulses is derived. The methodology is applied to obtain broadband excitation that is not only tolerant to RF inhomogeneity typical of high resolution probes, but is relatively insensitive to relaxation effects for T1 and T2 equal to the pulse length. The utility of designing pulses to produce specific phase in the final magnetization is also presented. The results regarding relaxation and optimized phase are quite general, with many potential applications beyond the specific examples presented here
Optimal Control Design of Excitation Pulses That Accommodate Relaxation
An optimal control algorithm for mitigating the effects of T1 and T2 relaxation during the application of long pulses is derived. The methodology is applied to obtain broadband excitation that is not only tolerant to RF inhomogeneity typical of high resolution probes, but is relatively insensitive to relaxation effects for T1 and T2 equal to the pulse length. The utility of designing pulses to produce specific phase in the final magnetization is also presented. The results regarding relaxation and optimized phase are quite general, with many potential applications beyond the specific examples presented here
Optimal Control Design of Excitation Pulses That Accommodate Relaxation
An optimal control algorithm for mitigating the effects of T1 and T2 relaxation during the application of long pulses is derived. The methodology is applied to obtain broadband excitation that is not only tolerant to RF inhomogeneity typical of high resolution probes, but is relatively insensitive to relaxation effects for T1 and T2 equal to the pulse length. The utility of designing pulses to produce specific phase in the final magnetization is also presented. The results regarding relaxation and optimized phase are quite general, with many potential applications beyond the specific examples presented here
The Fantastic Four: A Plug âNâ Play Set of Optimal Control Pulses for Enhancing NMN Spectroscopy
We present highly robust, optimal control-based shaped pulses designed to replace all 90° and 180° hard pulses in a given pulse sequence for improved performance. Special attention was devoted to ensuring that the pulses can be simply substituted in a one-to-one fashion for the original hard pulses without any additional modification of the existing sequence. The set of four pulses for each nucleus therefore consists of 90° and 180° point-to-point (PP) and universal rotation (UR) pulses of identical duration. These 1 ms pulses provide uniform performance over resonance offsets of 20 kHz (1H) and 35 kHz (13C) and tolerate reasonably large radio frequency (RF) inhomogeneity/miscalibration of ±15% (1H) and ±10% (13C), making them especially suitable for NMR of small-to-medium-sized molecules (for which relaxation effects during the pulse are negligible) at an accessible and widely utilized spectrometer field strength of 600 MHz. The experimental performance of conventional hard-pulse sequences is shown to be greatly improved by incorporating the new pulses, each set referred to as the Fantastic Four (Fanta4)
The Fantastic Four: A Plug âNâ Play Set of Optimal Control Pulses for Enhancing NMN Spectroscopy
We present highly robust, optimal control-based shaped pulses designed to replace all 90° and 180° hard pulses in a given pulse sequence for improved performance. Special attention was devoted to ensuring that the pulses can be simply substituted in a one-to-one fashion for the original hard pulses without any additional modification of the existing sequence. The set of four pulses for each nucleus therefore consists of 90° and 180° point-to-point (PP) and universal rotation (UR) pulses of identical duration. These 1 ms pulses provide uniform performance over resonance offsets of 20 kHz (1H) and 35 kHz (13C) and tolerate reasonably large radio frequency (RF) inhomogeneity/miscalibration of ±15% (1H) and ±10% (13C), making them especially suitable for NMR of small-to-medium-sized molecules (for which relaxation effects during the pulse are negligible) at an accessible and widely utilized spectrometer field strength of 600 MHz. The experimental performance of conventional hard-pulse sequences is shown to be greatly improved by incorporating the new pulses, each set referred to as the Fantastic Four (Fanta4)