Formula Used:
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Effective Transverse Relaxation Time (T2'), also known as dephasing time, is a combination of transverse relaxation and magnetic field inhomogeneity. It represents the time constant for the decay of transverse magnetization in NMR spectroscopy.
The calculator uses the formula:
Where:
Explanation: This formula calculates the effective transverse relaxation time from the phenomenological linewidth of the resonance lineshape, which is a primary factor affecting both resolution and signal-to-noise ratio of NMR spectra.
Details: Accurate T2' estimation is crucial for understanding spin-spin relaxation processes, optimizing NMR pulse sequences, and interpreting spectral line shapes in magnetic resonance experiments.
Tips: Enter the observed width at half-height in units of 1/second. The value must be positive and non-zero for accurate calculation.
Q1: What is the difference between T2 and T2'?
A: T2 represents the intrinsic transverse relaxation time, while T2' includes both intrinsic relaxation and external field inhomogeneity effects.
Q2: How does field inhomogeneity affect T2'?
A: Magnetic field inhomogeneity causes additional dephasing of spins, leading to a shorter effective transverse relaxation time (T2') compared to the intrinsic T2.
Q3: What are typical values for T2'?
A: T2' values vary widely depending on the sample and magnetic field strength, typically ranging from milliseconds to seconds in biological tissues.
Q4: How can T2' be measured experimentally?
A: T2' can be measured using various NMR pulse sequences such as gradient echo sequences or by analyzing the linewidth of NMR spectra.
Q5: Why is π used in the formula?
A: The factor of π comes from the relationship between the full width at half maximum of a Lorentzian lineshape and the relaxation time constant.