If we're running a CPMG T2, and wish to get all we can out of our Minispec,
we obviously want to push for a short tau and enough data points to adequately
describe the multicomponent decay. According to
the Bruker folks, we should be limiting ourselves to a tau limit of 40
microseconds for
rf pulses at 20 MHz, with the duty cycle not exceeding ~ 10%.
This makes sense for the duration of the pulse train (say 2000 echoes,
collecting
1000 data points on odd echoes to account for possible pi pulse errors).
My question is this:
If we go to longer delays between the echo trains (the relaxation delays),
how does
one mathematically incorporate (if possible) the delay time into the
calculated duty
cycle. Doing something like:
Duty = (2000 x pi)/((pi+tau)*2000 + RD)*100
just doesn't seem to accurately reflect the duty.
Any suggestions for us, the mathematically feeble? Has anyone else out there
consistently punished their minispec beyond the suggested 40 microsecond tau
limit without frying transmitters on a semi-regular basis? All replies
graciously accepted.
Thanks,
Tim Bremner
Tim Bremner - bremnet@novachem.com
Nova Research and Technology Center
Opinions expressed are the authors, and not Nova's
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