LET
LET is a direct-geometry, cold-neutron spectrometer at the ISIS Neutron and Muon Source. [1]
References
Versions
LET (default)
LET
For details on the parameters associated with the LET version, please see the LET data.
Models
PyChop_fit (default)
PyChop_fit
This is the recommended PyChop_fit model - it is an alias for the PyChop_fit_v1 model, which is the model actually containing the data.
Important
PyChop_fit refers to the best version of this model - using a specific version may run the risk using a model with known bugs or other issues and is not advisable unless replicating the results of a given version of the model.
PyChop_fit_v1
This section contains the data for the LET instrument associated with the PyChop_fit_v1 model. For more information about how the model works and its implementation, please see resins.models.pychop.PyChopModelLET. For more information on the model parameters, please see PyChop_fit_v1 model data.
Configurations:
-
High Flux (default)
Data
name: "LET"
default_version: "LET"
version:
LET:
default_model: "PyChop_fit"
models:
PyChop_fit: "PyChop_fit_v1"
PyChop_fit_v1:
function: "pychop_fit_let"
citation: ['R. I. Bewley, R. A. Ewings, M. D. Le, T. G. Perring and D. J. Voneshen, 2018. PyChop', 'https://mantidproject.github.io/docs-versioned/v6.10.0/interfaces/direct/PyChop.html']
parameters:
d_chopper_sample: 1.5
d_sample_detector: 3.5
aperture_width: 0.0
theta: 32.0
defaults:
e_init: 20
resolution_frequency: 240
pulse_remover_frequency: 120
restrictions:
e_init: [0.0, 30.0]
resolution_frequency: [10, 301, 10]
pulse_remover_frequency: [10, 301, 10]
constant_frequencies: [0, 10, 0, 0, 0]
source_frequency: 10
n_frame: 1
tjit: 0.0
moderator:
type: 3
scaling_function: None
measured_wavelength: [3.8063, 2.1961, 6.2121, 5.382, 1.4371, 1.701, 2.692, 1.9013]
measured_width: [90.4, 40.8, 154.4, 131.2, 22.4, 25.6, 52.4, 32.4]
parameters: [0.535, 49.28, -3.143]
detector: None
sample: None
configurations:
chopper_package:
default_option: "High Flux"
High Flux:
frequency_matrix: [[0, 0.5], [0, 0], [0, 1], [0.5, 0], [1, 0]]
choppers: {'ResolutionDisk': {'distance': 7.83, 'nslot': 6, 'slot_ang_pos': None, 'slot_width': 40.0, 'guide_width': 40.0, 'radius': 290.0, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0}, 'FrameOverlapDisk': {'distance': 8.4, 'nslot': 1, 'slot_width': 890, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 545, 'num_disk': 1, 'is_phase_independent': True, 'default_phase': 5}, 'PulseRemoverDisk': {'distance': 11.75, 'nslot': 2, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ContaminationRemoverDisk': {'distance': 15.66, 'nslot': 6, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ResolutionDisk2': {'distance': 23.5, 'nslot': 2, 'slot_ang_pos': None, 'guide_width': 20, 'radius': 290, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0, 'slot_width': 31}}
Intermediate:
frequency_matrix: [[0, 0.5], [0, 0], [0, 1], [0.5, 0], [1, 0]]
choppers: {'ResolutionDisk': {'distance': 7.83, 'nslot': 6, 'slot_ang_pos': None, 'slot_width': 40.0, 'guide_width': 40.0, 'radius': 290.0, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0}, 'FrameOverlapDisk': {'distance': 8.4, 'nslot': 1, 'slot_width': 890, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 545, 'num_disk': 1, 'is_phase_independent': True, 'default_phase': 5}, 'PulseRemoverDisk': {'distance': 11.75, 'nslot': 2, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ContaminationRemoverDisk': {'distance': 15.66, 'nslot': 6, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ResolutionDisk2': {'distance': 23.5, 'nslot': 2, 'slot_ang_pos': None, 'guide_width': 20, 'radius': 290, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0, 'slot_width': 20}}
High Resolution:
frequency_matrix: [[0.5, 0], [0, 0], [0, 1], [0, 1], [1, 0]]
choppers: {'ResolutionDisk': {'distance': 7.83, 'nslot': 6, 'slot_ang_pos': None, 'slot_width': 40.0, 'guide_width': 40.0, 'radius': 290.0, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0}, 'FrameOverlapDisk': {'distance': 8.4, 'nslot': 1, 'slot_width': 890, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 545, 'num_disk': 1, 'is_phase_independent': True, 'default_phase': 5}, 'PulseRemoverDisk': {'distance': 11.75, 'nslot': 2, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ContaminationRemoverDisk': {'distance': 15.66, 'nslot': 6, 'slot_width': 56, 'slot_ang_pos': None, 'guide_width': 40, 'radius': 290, 'num_disk': 1, 'is_phase_independent': False, 'default_phase': 0}, 'ResolutionDisk2': {'distance': 23.5, 'nslot': 2, 'slot_ang_pos': None, 'guide_width': 20, 'radius': 290, 'num_disk': 2, 'is_phase_independent': False, 'default_phase': 0, 'slot_width': 15}}