76 lines
3.0 KiB
Python
76 lines
3.0 KiB
Python
# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Davis V. Garrad <davis.last@psi.ch>
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# Tina Arh <tina.arh@psi.ch>
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#
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# *****************************************************************************
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# Select the parameters that are written under environment in HDF file at every write
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SetEnvironment(tt, mf, nmr_TSSOP16, nmr_RP100Node_CH1, nmr_RP100Node_CH2, r1, tps)#, ZVLNode)
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# PPMS: Set field & temperature
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#maw(tt, 3) # set PPMS temperature (in Kelvin)
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#maw(mf, 3) # set the starting PPMS field (in Tesla)
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#nicossleep(20*60) # 20 minutes
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# ...
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# Create the pulse sequence
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pw90 = 2.5 # us
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amp = 40 # percent
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tau = 50 # us
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# generate_pulse(pulse_width, amplitude, delay_time, pulse_cycle)
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p90 = generate_pulse(pw90, amp, tau, '0 0 2 2 1 1 3 3 0 0 2 2 1 1 3 3')
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p180_2 = generate_pulse(2*pw90, amp, 0, '1 3 3 1 2 0 0 2 0 2 2 0 3 1 1 3')
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seq = [ p90, p180_2 ]
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# Create the list of sequences to scan (for a T2 scan, the delay after the first pulse - tau - increases linearly from tau_min to tau_max)
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tau_min = 50 # us
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tau_max = 20000 # us
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n_points = 20
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delay_times = [tau_min + i * (tau_max - tau_min) / (n_points - 1) for i in range(n_points)]
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# Generates a list of sequences; copies of seq are made, only the zeroth pulse is modified. Each copy is given a 'delay_time' value from delay_times
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seq_list = generate_sequences(seq, [0], 'delay_time', delay_times)
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# We now modify the delay after the second pulse to be a fixed time shorter than tau, this means the spin echo will always appear at the same time after the start of acquisition
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for i in range(len(seq_list)):
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seq_list[i][1]['delay_time'] = max(seq_list[i][0]['delay_time'] - 20.0, 0.1)
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# Set some parameters independent of pulse sequence
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globalparams = {
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'acq_phase_cycle': '0 0 2 2 1 1 3 3 2 2 0 0 3 3 1 1',
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'acquisition_time': 204.8, # us
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'num_acqs': 4096, # "1D scans" in TNMR. Our 16-fold phase cycling means this should be a multiple of 16 for proper averaging
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'ringdown_time': 5, # us
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'post_acquisition_time': 100, # ms
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'obs_freq': 42.09, # MHz
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'nucleus': '139La', # For example, 139La. Will be used in a filename!
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'comments': 'An example of a T2 scan',
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'title': 'T2', # Goes at the beginning of a filename!
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}
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update_device_parameters(nmr_daq_scout, globalparams)
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# Acquire data
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scan_sequences(nmr_daq_scout, seq_list) # gather the data
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