# -*- 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(): # saturation-recovery 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'] = 200e3 # spectral window (Hz) pars['SI'] = 1*256 # number of acquisition points pars['NS'] = 8 # number of scans pars['DS'] = 0 # number of dummy scans pars['TAU'] = 1 # delay for recovery (s) pars['DEAD1'] = 5e-6 # receiver dead time (s) pars['PHA'] = 100 # receiver phase (degree) # -*- these aren't variable: -*- pars['NECH'] = 40 # number of saturation pulses pars['D1'] = 100e-3 # starting interval in saturation sequence (s) pars['D2'] = 1e-4 # end interval in saturation sequence (s) pars['DATADIR'] = '/home/fprak/Students/' # data directory pars['OUTFILE'] = None # output file name # specify a variable parameter (optional): pars['VAR_PAR'] = 'TAU' # variable parameter name (a string) start = 1e-3 # starting value stop = 5e-0 # end value steps = 10 # number of values log_scale = True # 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']%4 != 0: pars['NS'] = int(round(pars['NS'] / 4) + 1) * 4 print 'Number of scans changed to ',pars['NS'],' due to phase cycling' if pars['D1'] < pars['D2']: raise Exception("D1 must be greater than D2") sat_length = sum(log_range(pars['D1'],pars['D2'],pars['NECH'])) if sat_length > 1.: raise Exception("Saturation sequence too long!!!") # 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 = (sat_length * steps + sum(array)) * (pars['NS'] + pars['DS']) else: seconds = (sat_length + pars['TAU']) * 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 satrec_experiment(pars, run) synchronize() else: # estimate the experiment time: seconds = (sat_length + pars['TAU']) * (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 satrec_experiment(pars, run) # the pulse program: def satrec_experiment(pars, run): e=Experiment() dummy_scans = pars.get('DS') if dummy_scans: run -= dummy_scans pars['PROG'] = 'satrec_experiment' # phase lists: pars['PH1'] = [0] # saturation pulses pars['PH3'] = [0,180,90,270] # measuring pulse pars['PH2'] = [0,180,90,270] # receiver # read in variables: P90 = pars['P90'] SF = pars['SF'] O1 = pars['O1'] DEAD1 = pars['DEAD1'] NECH = pars['NECH'] D1 = pars['D1'] D2 = pars['D2'] TAU = pars['TAU'] 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 # set variable delay list for saturation pulses: vdlist = log_range(D2, D1, NECH-1) # run the pulse sequence: # saturation: e.set_frequency(SF+O1, phase=PH1) # set frequency and phase for saturation pulses e.ttl_pulse(TXEnableDelay, value=TXEnableValue) # enable RF amplifier e.ttl_pulse(P90, value=TXEnableValue|TXPulseValue) # apply 90-degree pulse for delay in vdlist[::-1]: e.wait(delay-P90-TXEnableDelay) # wait for next pulse e.ttl_pulse(TXEnableDelay, value=TXEnableValue) # enable RF amplifier e.ttl_pulse(P90, value=TXEnableValue|TXPulseValue) # apply 90-degree pulse # recovery: e.wait(TAU) # recovery time e.set_phase(PH3) # set phase for measuring pulse # detection: e.ttl_pulse(TXEnableDelay, value=TXEnableValue) # enable RF amplifier e.ttl_pulse(P90, value=TXEnableValue|TXPulseValue) # apply 90-degree pulse e.set_phase(PHA) # set phase for receiver e.wait(DEAD1) # wait for coil ringdown e.record(SI, SW, sensitivity=ADCSensitivity) # acquire signal # write experiment parameters: for key in pars.keys(): e.set_description(key, pars[key]) # acquisition parameters e.set_description('run', run) # current scan e.set_description('rec_phase', -PH2) # current receiver phase return e