DOI: 10.48420/26038057.v1
title: Rationalising spin relaxation during slice-selective refocusing pulses

description: "Rationalising spin relaxation during slice-selective refocusing pulses"Experimental data for six doped water samples [/Experimental_doped_water/]===========<br>These data were used to generate Figure 2 and Table 2 in the main manuscript, as well as Figures S1-S7, Figure S11, Figure S12, Tables S5-S11 and Table S13 in the Supporting Information.<br>These data were analysed using the "UoM_RSR_lsqcurvefit" and "UoM_queue_RSR_lsqcurvefit" MATLAB functions.<br><br>Experimental_doped_water_integrals - Spreadsheet containing the absolute integrals obtained from slice-selective spin echo experiments performed on doped water samples 1-6<br>Directory structure for experimental data for doped water samples 1-5 (see Table 1 in main manuscript):<br>4 - 1H pulse-acquire NMR experiment5 - 1H inversion recovery NMR experiment (GNAT data in "GNAT" subfolder)6 - 1H Carr-Purcell Method A NMR experiment (GNAT data in "GNAT" subfolder)101-110 - Slice-selective spin echo NMR experiments using an rSNOB refocusing pulse of varying duration111-120 - Slice-selective spin echo NMR experiments using a REBURP refocusing pulse of varying duration121-130 - Slice-selective spin echo NMR experiments using a Gaussian refocusing pulse of varying duration131-140 - Slice-selective spin echo NMR experiments using a rectangular refocusing pulse of varying duration<br><br>Directory structure for experimental data for doped water sample 6 (see Table 1 in main manuscript):<br>4 - 1H pulse-acquire NMR experiment5 - 1H inversion recovery NMR experiment (GNAT data in "GNAT" subfolder)6 - 1H Carr-Purcell Method A NMR experiment (GNAT data in "GNAT" subfolder)101-113 - Slice-selective spin echo NMR experiments using an rSNOB refocusing pulse of varying duration121-133 - Slice-selective spin echo NMR experiments using a REBURP refocusing pulse of varying duration141-153 - Slice-selective spin echo NMR experiments using a Gaussian refocusing pulse of varying duration161-173 - Slice-selective spin echo NMR experiments using a rectangular refocusing pulse of varying duration<br><br>==========Simulated data for the six doped water samples [/Simulation_doped_water/]=========<br>These data were used to generate Figure 2 and Table 2 in the main manuscript, as well as Figures S1-S10, Tables S5-S11, Table S13 and Table S14 in the Supporting Information.<br>These data were analysed using the "UoM_RSR_lsqcurvefit" and "UoM_queue_RSR_lsqcurvefit" MATLAB functions.<br><br>The data from each simulation is contained within a numbered folder. Three parameters are varied across the 252 simulations, in following order of precedence: pulse duration, sample (i.e., T1 and T2 time constants), and pulse shape. The T1 and T2 relaxation time constants matched those of the experimental samples.<br>1-63 - Slice-selective spin echo NMR Spinach simulations using an rSNOB refocusing pulse of varying duration performed on doped water samples 1-664-126 - Slice-selective spin echo NMR Spinach simulations using a REBURP refocusing pulse of varying duration performed on doped water samples 1-6127-189 - Slice-selective spin echo NMR Spinach simulations using a Gaussian refocusing pulse of varying duration performed on doped water samples 1-6190-252 - Slice-selective spin echo NMR Spinach simulations using a rectangular refocusing pulse of varying duration performed on doped water samples 1-6<br><br>==================================================================================================================================================================================Analysis of the experimental and simulated doped water data [/Analysis_doped_water/]===========<br>Analysis of the experimental and simulated doped water data were used to generate Figure 2 and Table 2 in the main manuscript, as well as Figures S1-S12 and Tables S5-S14 in the Supporting Information.<br>The two functions used to perform this analysis were the "UoM_RSR_lsqcurvefit" and "UoM_queue_RSR_lsqcurvefit" functions. The specific functions used to perform each analysis maybe found, along with the analysis output, in the subfolders of this directory.<br>UoM_RSR_lsqcurvefit: MATLAB function used to perform global fitting of the data from slice-selective spin echo NMR experiments and Spinach simulations performed on the six doped water samples to various proposed relaxational attenuation modelsUoM_queue_RSR_lsqcurvefit: MATLAB function used to queue calls to the "UoM_RSR_lsqcurvefit" function and provide input parameters for the processing and analysis. These input parameters may be found in the "params.mat" files.<br><br>ModelFitting - Global fitting of the experimental and simulated doped water data to seven different models of relaxational attenuation (Figure 2 and Table 2 in the main manuscript, as well as Figures S1-S7 and Tables S5-S11 in the Supporting Information)OnRes - Global fitting of the simulated doped water data from an on-resonance frequency-selective spin echo simulation (Figure S8 and Table S12 in the Supporting Information)Residuals - An examination of the residuals surface when performing global fitting (Figures S9-S12 in the Supporting Information)OppositeFitting - An examination of the residuals when fitting the simulated data with the optimal alpha and beta values determined for the experimental data, and vice versa (Table S13 in the Supporting Information)Fidelity - An investigation into the fidelity of the Spinach simulations performed by performing global fitting with different offset spacings (Table S14 in the Supporting Information)<br><br>========Simulated data in the linear attenuation regime [/Simulation_linear_attenuation/]=========<br>These data were used to generate Figure 3 and Table 3 in the main manuscript.<br>UoM_RSR_r1r2_offset_dependence - MATLAB function used to analyse the data from Spinach simulations of slice-selective spin echo experiments in the linear attenuation regime<br>1-4 - Slice-selective spin echo NMR Spinach simulations using a 10 ms rSNOB refocusing pulse, performed on single-spin systems with small differences in T1 and T2 5-8 - Slice-selective spin echo NMR Spinach simulations using a 10 ms REBURP refocusing pulse, performed on single-spin systems with small differences in T1 and T2 9-12 - Slice-selective spin echo NMR Spinach simulations using a 10 ms Gaussian refocusing pulse, performed on single-spin systems with small differences in T1 and T2 13-16 - Slice-selective spin echo NMR Spinach simulations using a 10 ms rectangular refocusing pulse, performed on single-spin systems with small differences in T1 and T2Analysis - Contains the output of the analysis of these data performed using the "UoM_RSR_r1r2_offset_dependence" function<br><br>=========Diffusional attenuation analysis [/Diffusional_attenuation/]==========<br>These data were used to generate Figure S13 in the Supporting Information.<br>UoM_RSR_diffusional_atten - MATLAB function used to predict the HDO signal loss due to diffusional attenuation in the slice-selective spin echo NMR experiments performed on the six doped water samples<br><br>=========Bloch sphere simulations [/Bloch_spheres/]==========<br>These data were used to generate Figure 1 in the main manuscript and Table S15 in the Supporting Information.<br>UoM_RSR_Bloch_spheres - Mathematica notebook used to calculate magnetisation trajectories in the Bloch sphere by numerical integration<br>UoM_RSR_diffusional_atten - MATLAB function used to predict the HDO signal loss due to diffusional attenuation in the slice-selective spin echo NMR experiments performed on the six doped water samples<br><br>=========Bloch sphere simulations [/Bloch_spheres/]==================================================================================================================================================================================<br>These data were used to generate Figure 1 in the main manuscript and Table S15 in the Supporting Information.<br>UoM_RSR_Bloch_spheres - Mathematica notebook used to calculate magnetisation trajectories in the Bloch sphere by numerical integration