# na-spam-echo-selective-filtering-p1.in

# approach: filtering the desired coherences (-3Q)  after the first pulse
#           and (±3Q, ±2Q, ±1Q, and 0Q) after the second pulse

# spin-3/2 echo amplitude optimization
# versus the first-pulse duration
# in three-pulse spam -3Q-MAS sequence,
# the second-pulse duration p2 = 4 micro seconds
# the third-pulse duration p3 = 2 micro seconds

spinsys {
  channels 23Na
  nuclei   23Na
  quadrupole 1 1 1e6 1 0 0 0
}

par {
  spin_rate        5000
  variable tsw     0.25
  sw               1.0e6/tsw
  np               17
  crystal_file     rep10
  gamma_angles     10
  proton_frequency 800e6
  start_operator   12*I1z
  detect_operator  I1c
  verbose          1101
  variable rf      90000
  variable rf3     9300
  variable p2      4 
  variable p3      2 
}

proc pulseq {} {
  global par
  maxdt $par(tsw)

  matrix set 1 coherence {-3}
  matrix set 2 coherence {9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9}

  acq -y        
  for {set i 1} {$i < $par(np)} {incr i} {
    pulse $par(tsw) $par(rf) x
    store 2
    filter 1
    pulse $par(p2)  $par(rf) x
    filter 2
    pulse $par(p3) $par(rf3) -x
    acq -y
    reset
    prop 2
  }
}

proc main {} {
  global par

  fsave [fsimpson] $par(name).fid
  puts "Larmor frequency (Hz) of 23Na: "
  puts [resfreq 23Na $par(proton_frequency)]
}

# SIMP
# NP=17
# SW=4000000
# TYPE=FID
# DATA
# 0 0
# 2.38508572e-05 -2.86856067e-18
# 0.000727400625 2.5000203e-18
# 0.0050896491 2.45152802e-18
# 0.0191407993 -7.07549916e-18
# 0.0506122157 4.26838518e-18
# 0.106288417 -1.71153765e-17
# 0.189627961 -8.88842164e-17
# 0.299897436 -1.87795276e-16
# 0.432969353 -1.7851658e-16
# 0.582908295 -3.36782794e-16
# 0.743224232 -4.78651225e-16
# 0.907279514 -5.34886149e-16
# 1.06822157 -5.89206167e-16
# 1.21924007 -4.01299706e-16
# 1.35459776 -3.92979894e-16
# 1.47108365 -2.05594308e-16
# END