Emittance Measurement Class #198
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shamin-slac
commented
Sep 26, 2024
shamin-slac
commented
- This class provides a measure() method for computing the emittance given magnet and screen/wire settings
- Beam size is retrieved directly from the screen/wire
- rmats are taken from the Model (imported from meme.model) initialized for some beamline
- Initialize attributes as properties
| from meme.model import Model | ||
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| class QuadScanEmittance(Measurement): | ||
| model_beamline: str |
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Instead of passing model_beamline, magnet_area, magnet_name, I would define a field
magnet_collection: MagnetCollection, same for the measurement_device class (which will have the area attribute inside of it). These can be public attributes that get dumped with everything else since they are pydantic objects
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these fields should be required
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We can also make it so that we can pass a string to these attributes, for that you would use the following code for example in the magnet_collection class
@field_validator("magnet_collection", mode="before")
def validate_magnet_collection(cls, value):
if isinstance(value, str):
value = create_magnet_collection(value)
return value- Replace device attribute with device_measurement - Replace get_beamsize() method with device_measurement.measure() method
…nce measurement class
| gets the rmat and twiss parameters, then computes and returns the emittance and BMAG | ||
| measure_beamsize: take measurement from measurement device, store beam sizes | ||
| """ | ||
| name: str = "emittance_profile" |
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maybe just name it emittance? emittance_profile doesn't mean much
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@dylanmkennedy can you draft a prototype run notebook for diag0 using the current code in Shamin's branch to see if we are missing anything? |
tests/unit_tests/lcls_tools/common/measurements/test_emittance_measurement.py
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- Add x_rms and y_rms to output of emittance measure method - Raise NotImplementedError for MultiDeviceEmittance measure method and compute_emit_bmag - Shorten mock values in test_emittance_measurement
- Get rmats at 'mid' of from_device (the magnet) - Get twiss at measurement_device (the screen) - Use just x rmat and y rmat for compute_emit_bmag
| self.beam_sizes["x_rms"] = [] | ||
| if "y_rms" not in self.beam_sizes: | ||
| self.beam_sizes["y_rms"] = [] | ||
| self.beam_sizes["x_rms"].append(np.mean(results["Sx"])) |
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where is Sx coming from? and why the mean?
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Sx is coming from the GaussianFit method, a separate PR can be used to change this. I've added in a n_shots key to the emittance measurement class to allow for averaging over multiple shots
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Ok, will merge as is and can you please write two issues related to this:
- address the Sx
- We need to return error bars when averaging (or am I missing that here?)
tests/unit_tests/lcls_tools/common/measurements/test_emittance_measurement.py
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| results = { | ||
| "emittance": emittance, | ||
| "BMAG": bmag, |
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does BMAG need to be capitalized?
| self.beam_sizes["x_rms"] = [] | ||
| if "y_rms" not in self.beam_sizes: | ||
| self.beam_sizes["y_rms"] = [] | ||
| self.beam_sizes["x_rms"].append(np.mean(results["Sx"])) |
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Ok, will merge as is and can you please write two issues related to this:
- address the Sx
- We need to return error bars when averaging (or am I missing that here?)
