147 lines
5.3 KiB
Python
147 lines
5.3 KiB
Python
# -*- coding: iso-8859-1 -*-
|
|
|
|
TXEnableDelay = 2e-6
|
|
TXEnableValue = 0b0001 # TTL line blanking RF amplifier (bit 0)
|
|
TXPulseValue = 0b0010 # TTL line triggering RF pulses (bit 1)
|
|
ADCSensitivity = 2 # voltage span for ADC
|
|
|
|
def experiment(): # solid echo (quadrupolar echo) experiment
|
|
|
|
# set up acquisition parameters:
|
|
pars = {}
|
|
pars['P90'] = 1.7e-6 # 90-degree pulse length (s)
|
|
pars['SF'] = 338.7e6 # spectrometer frequency (Hz)
|
|
pars['O1'] = -60e3 # offset from SF (Hz)
|
|
pars['SW'] = 500e3 # spectral window (Hz)
|
|
pars['SI'] = 1*1024 # number of acquisition points
|
|
pars['NS'] = 8 # number of scans
|
|
pars['DS'] = 0 # number of dummy scans
|
|
pars['RD'] = 3 # delay between scans (s)
|
|
pars['TAU'] = 20e-6 # echo delay (s)
|
|
pars['D4'] = 0e-6 # echo pre-acquisition delay (s)
|
|
pars['PHA'] = -30 # receiver phase (degree)
|
|
pars['DATADIR'] = '/home/fprak/Students/' # data directory
|
|
pars['OUTFILE'] = None # output file name
|
|
|
|
# specify a variable parameter (optional):
|
|
pars['VAR_PAR'] = None # variable parameter name (a string)
|
|
start = 1e-6 # starting value
|
|
stop = 3e-6 # end value
|
|
steps = 3 # number of values
|
|
log_scale = False # log scale flag
|
|
stag_range = False # staggered range flag
|
|
|
|
# check parameters for safety:
|
|
if pars['PHA'] < 0:
|
|
pars['PHA'] = 360 + pars['PHA']
|
|
|
|
if pars['P90'] > 20e-6:
|
|
raise Exception("Pulse too long!!!")
|
|
|
|
# check whether a variable parameter is named:
|
|
var_key = pars.get('VAR_PAR')
|
|
if var_key == 'P90' and (start > 20e-6 or stop > 20e-6):
|
|
raise Exception("Pulse too long!!!")
|
|
|
|
if pars['NS']%8 != 0:
|
|
pars['NS'] = int(round(pars['NS'] / 8) + 1) * 8
|
|
print 'Number of scans changed to ',pars['NS'],' due to phase cycling'
|
|
|
|
# start the experiment:
|
|
if var_key:
|
|
# this is an arrayed experiment:
|
|
if log_scale:
|
|
array = log_range(start,stop,steps)
|
|
else:
|
|
array = lin_range(start,stop,steps)
|
|
|
|
if stag_range:
|
|
array = staggered_range(array, size = 2)
|
|
|
|
# estimate the experiment time:
|
|
if var_key == 'TAU':
|
|
seconds = (sum(array)*2 + pars['RD'] * steps) * (pars['NS'] + pars['DS'])
|
|
elif var_key == 'RD':
|
|
seconds = (sum(array) + pars['TAU']*2 * steps) * (pars['NS'] + pars['DS'])
|
|
else:
|
|
seconds = (pars['TAU']*2 + pars['RD']) * steps * (pars['NS']+ pars['DS'])
|
|
m, s = divmod(seconds, 60)
|
|
h, m = divmod(m, 60)
|
|
print '%s%02d:%02d:%02d' % ('Experiment time estimated: ', h, m, s)
|
|
|
|
# loop for a variable parameter:
|
|
for index, pars[var_key] in enumerate(array):
|
|
print 'Arrayed experiment for '+var_key+': run = '+str(index+1)+\
|
|
' out of '+str(array.size)+': value = '+str(pars[var_key])
|
|
# loop for accumulation:
|
|
for run in xrange(pars['NS']+pars['DS']):
|
|
yield solidecho_experiment(pars, run)
|
|
synchronize()
|
|
else:
|
|
# estimate the experiment time:
|
|
seconds = (pars['TAU']*2 + pars['RD']) * (pars['NS']+ pars['DS'])
|
|
m, s = divmod(seconds, 60)
|
|
h, m = divmod(m, 60)
|
|
print '%s%02d:%02d:%02d' % ('Experiment time estimated: ', h, m, s)
|
|
|
|
# loop for accumulation:
|
|
for run in xrange(pars['NS']+pars['DS']):
|
|
yield solidecho_experiment(pars, run)
|
|
|
|
|
|
# the pulse program:
|
|
|
|
def solidecho_experiment(pars, run):
|
|
e=Experiment()
|
|
|
|
dummy_scans = pars.get('DS')
|
|
if dummy_scans:
|
|
run -= dummy_scans
|
|
|
|
pars['PROG'] = 'solidecho_experiment'
|
|
|
|
# phase lists [from Tecmag's pulse sequence]:
|
|
pars['PH1'] = [ 0, 180, 0, 180, 90, 270, 90, 270] # 1st 90-degree pulse
|
|
pars['PH3'] = [90, 90, 270, 270, 0, 0, 180, 180] # 2nd 90-degree pulse
|
|
pars['PH2'] = [ 0, 180, 0, 180, 90, 270, 90, 270] # receiver
|
|
|
|
|
|
# read in variables:
|
|
P90 = pars['P90']
|
|
SF = pars['SF']
|
|
O1 = pars['O1']
|
|
RD = pars['RD']
|
|
TAU = pars['TAU']
|
|
D4 = pars['D4']
|
|
PH1 = pars['PH1'][run%len(pars['PH1'])]
|
|
PH3 = pars['PH3'][run%len(pars['PH3'])]
|
|
PH2 = pars['PH2'][run%len(pars['PH2'])]
|
|
PHA = pars['PHA']
|
|
|
|
# set sampling parameters:
|
|
SI = pars['SI']
|
|
SW = pars['SW']
|
|
while SW <= 10e6 and SI < 256*1024:
|
|
SI *= 2
|
|
SW *= 2
|
|
|
|
# run the pulse sequence:
|
|
e.wait(RD) # delay between scans
|
|
e.set_frequency(SF+O1, phase=PH1) # set frequency and phase for 1st RF pulse
|
|
e.ttl_pulse(TXEnableDelay, value=TXEnableValue) # enable RF amplifier
|
|
e.ttl_pulse(P90, value=TXEnableValue|TXPulseValue) # apply 1st 90-degree pulse
|
|
e.wait(TAU-P90/2-TXEnableDelay) # wait for TAU
|
|
e.set_phase(PH3) # set phase for 2nd 90-degree pulse
|
|
e.ttl_pulse(TXEnableDelay, value=TXEnableValue) # enalble RF amplifier
|
|
e.ttl_pulse(P90, value=TXEnableValue|TXPulseValue) # apply 2nd 90-degree pulse
|
|
e.set_phase(PHA) # set phase for receiver
|
|
e.wait(TAU-P90/2+D4) # wait for TAU
|
|
e.record(SI, SW, sensitivity=ADCSensitivity) # acquire echo points
|
|
|
|
# write the experiment parameters:
|
|
for key in pars.keys():
|
|
e.set_description(key, pars[key]) # pulse sequence parameters
|
|
e.set_description('run', run) # current scan
|
|
e.set_description('rec_phase', -PH2) # current receiver phase
|
|
|
|
return e |