Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Dual-compensated antisymmetric composite refocusing pulses for NMR
AU - Odedra, Smita
AU - Thrippleton, Michael J.
AU - Wimperis, Stephen
PY - 2012/12
Y1 - 2012/12
N2 - Novel antisymmetric composite 180 degrees pulses are designed for use in nuclear magnetic resonance (NMR) and verified experimentally. The pulses are simultaneously broadband with respect to both inhomogeneity of the radiofrequency (B-1) field and resonance offset and, as a result of their antisymmetric phase schemes, can be used to form spin echoes without the introduction of a phase error. The new dual-compensated pulses are designed analytically, using symmetry arguments and a graphical interpretation of average Hamiltonian theory. Two families of composite refocusing pulses are presented, one (ASBO-9) consisting of sequences made up of 9 simple 180 degrees pulses and one (ASBO-11) of sequences made up of 11 simple 180 degrees pulses. There are an infinite number of composite pulses in each family owing to a free phase variable in the solution to the average Hamiltonian equations and this allows selection of individual composite pulses with particular properties. Finally, a comparison is made between composite pulses designed using average Hamiltonian theory and those proposed for use in quantum computing by NMR. (C) 2012 Elsevier Inc. All rights reserved.
AB - Novel antisymmetric composite 180 degrees pulses are designed for use in nuclear magnetic resonance (NMR) and verified experimentally. The pulses are simultaneously broadband with respect to both inhomogeneity of the radiofrequency (B-1) field and resonance offset and, as a result of their antisymmetric phase schemes, can be used to form spin echoes without the introduction of a phase error. The new dual-compensated pulses are designed analytically, using symmetry arguments and a graphical interpretation of average Hamiltonian theory. Two families of composite refocusing pulses are presented, one (ASBO-9) consisting of sequences made up of 9 simple 180 degrees pulses and one (ASBO-11) of sequences made up of 11 simple 180 degrees pulses. There are an infinite number of composite pulses in each family owing to a free phase variable in the solution to the average Hamiltonian equations and this allows selection of individual composite pulses with particular properties. Finally, a comparison is made between composite pulses designed using average Hamiltonian theory and those proposed for use in quantum computing by NMR. (C) 2012 Elsevier Inc. All rights reserved.
KW - Composite pulses
KW - Symmetry
KW - B-1 inhomogeneity
KW - Resonance offset
KW - Phase cycling
KW - Pulse imperfections
KW - Error compensation
KW - BAND POPULATION-INVERSION
KW - BROAD-BAND
KW - ITERATIVE SCHEMES
KW - NARROW-BAND
KW - EXCITATION
KW - SEQUENCES
KW - SUPPRESSION
KW - SYSTEMS
KW - MAPS
U2 - 10.1016/j.jmr.2012.10.003
DO - 10.1016/j.jmr.2012.10.003
M3 - Journal article
VL - 225
SP - 81
EP - 92
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
SN - 1090-7807
ER -