; dsr_n15_T1
; arx-version
; simplified pulse sequence for T1 measurements
; good suppression of cross-correlation 
; direct detection of 15N with decoupling of 1H during acquisition
; includes centering pulses for INEPT (not really needed)
; DSR, Spring 2005


; Reference:
; Thompson, L.E., and Rovnyak.D,"Accessible NMR Experiments Studying the Hydrodynamics of 15N-enriched Ubiquitin at Low Fields", Submitted to Biochem. and Mol. Biol. Ed., 2005

d7 = (p2-p4)/2
d8 = (p1-p3)/2

1 ze 
2 d1 do dl0 
3 (p3 ph1):d 
  d4
  (d7 p4 ph2):d (p2 ph2)
  d4
  (d8 p3 ph3):d (p1 ph4)
  d4
  (d7 p4 ph2):d (p2 ph2) 
  d4
  p1 ph5
4 d5
  (p4 ph2):d
  d5
  lo to 4 times c
  p1 ph2
  20u dl5
  go=2 ph31 cpd
  wr #0 if #0 vc
  20u do
  lo to 1 times l4
exit

ph1  = 0 2
ph2  = 0
ph3  = 1 1 1 1 3 3 3 3
ph4  = 0 0 2 2
ph5  = 1 1 1 1 1 1 1 1 3 3 3 3 3 3 3 3
ph31 = 0 2 2 0 2 0 0 2 2 0 0 2 0 2 2 0


; tl0: transmitter power level (default)
; dl0: decoupler high power level
; dl5: decoupler power level for CPD/BB decoupling
; p1 :  90 degree transmitter high power pulse (15N)
; p2 : 180 degree transmitter high power pulse (15N)
; p3 :  90 degree decoupler high power pulse (1H)
; p4 : 180 degree decoupler high power pulse (1H)
; p31: 90 degree pulse for slave timer (cpd-sequence)
; d1 : relaxation delay; 1-5 * T1
; d4 : 1/(4J(XH)) ; 2.7 ms is ok
; d5 : half of the refocusing interval (since d5 used twice); suggest 5-10 ms
; l4 : the number of times to run the experiment
;     l4 corresponds to the number of different relaxation times that are tested
;     For educational work recommend using 4-5 different values (set l4 to 4)
;     For example, d5=7ms and a vclist of ( 2, 7, 20, 45, 100 ) would yield the 
;     relaxation times ( 28 ms, 98 ms, 280 ms, 630 ms, 1400 ms)
; NS: 16 * n  (ok to do 8 * n)
; DS: 4 
; cpd: cpd-decoupling according to sequence defined by cpdprg