Hi all!
I am trying to write a sequence for my old AC200 that does CPMG as
minispec (a 20 MHz Bruker spectrometer) does, but I am running into
problems. Maybe some of you have already done it in the right way...please
help!
Minispec does simply this:
---relax---90--tau--(180--2*tau--180--tau--take 1 point--tau)n
a SINGLE point is taken on the top of every second echo. This is
expecially useful when you want to take hundreds of echoes in a single
experiment. With the "normal" cpmg sequence you are forced to run a single
experiment for each echo, which is a big waste of time.
As I found that device X causes a single point to be digitized by the ADC
I wrote the attached sequence. In a way it works. "C" points are taken,
but what I am not sure about is WHEN the signal is taken. I mean, it is
surely digitized when P8:X is executed, but I have the impression that the
receiver remains on between one P8:X and the following, so that what I
digitize is actually the average signal the receiver sees between two P8:X
instructions. This is not of course what I want. I want to take just the
top of the echo.
Are there some Bruker gurus here that still remember any trick to make the
sequence work properly with my old machine?
Thank you very much!
Mauro
------------
; this sequence uses decoupler for pulsing because you
; cannot use TX and RX at the same time while aquiring
; with AC machines.
;
ZE
1 D1 S1 DO
P1:D PH1
D3 ; TAU-8 US
D5 ; 3.1 US
D7 ADC ; 1.8 US
D5 PH5 ; 3.1 US (values for DW=3 US)
8 P2:D PH2
D6 ;TAU
D6
P2:D PH2
D4 ; TAU - 1.5 US
P8:X ; 1 US
D8 ; 2 US ; P8+D8=DW
D4 PH5 ; TAU - 1.5 US
L1 TO 8 TIMES C
RCYC=1 PH3
EXIT
PH1= 0 0 2 2 1 1 3 3
PH2= 1 3 1 3 0 2 0 2
PH3= R1 R1 R3 R3 R2 R2 R0 R0
PH5= 0
============================================
Mauro Andrea Cremonini, PhD
Department of Food Science
University of Bologna
Via Ravennate 1020 - 47023 - Cesena - Italy
FAX:+39.0547.382348 - Phone:+39.0547.636106
e-mail: mac@foodsci.unibo.it
http://www.foodsci.unibo.it/cremonini
============================================
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