# na-spam-echo-selective-filtering-p2.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 second-pulse duration
# in three-pulse spam -3Q-MAS sequence,
# the first-pulse duration p1 = 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 p1      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}

  pulse  $par(p1) $par(rf) x
  store 10

  reset
  acq -y        
  for {set i 1} {$i < $par(np)} {incr i} {
    reset
    prop 10
    filter 1
    pulse [expr ($i)*$par(tsw)] $par(rf) x 
    filter 2
    pulse $par(p3) $par(rf3) -x
    acq -y
    }
}

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
# 0.135236263 -3.72381298e-17
# 0.488908227 -6.99339442e-17
# 1.02313553 -1.26563816e-16
# 1.61231779 -2.52934331e-16
# 2.13335276 -3.77976893e-16
# 2.49863914 -5.20666564e-16
# 2.67167155 -5.21684501e-16
# 2.66395758 -4.38486982e-16
# 2.51966833 -4.22283675e-16
# 2.29696575 -3.59374858e-16
# 2.05252661 -2.53575436e-16
# 1.83145293 -2.29262173e-16
# 1.66180846 -1.34502303e-16
# 1.55268571 -1.37639831e-16
# 1.49580481 -1.41486352e-16
# 1.47108365 -1.44678704e-16
# END