- Fix chi2 calculation bug in calibration.py (remove incorrect coeffs[::-1] reversal in np.polyval) - Fix broken beta_spectrum/cli.py (remove orphaned detector response add_argument calls and unused imports) - Add ExpSpectrum.apply_calibration() and EnergyCalibrator.from_am241_spectrum() - Add LivetimeDetermination class for pulser-based livetime - Add SpectrumPipeline orchestration (read→subtract→calibrate→livetime→validate) - Add ROOT I/O with PyROOT primary + uproot fallback - Add bs_exp CLI with process, livetime, export subcommands - Add exp_calibration notebook with pre-calibration visualization - Add comprehensive tests (73 passing) - Add bs_exp console script and [root] extra to pyproject.toml - Remove obsolete detector_response module and unused notebooks
212 lines
7.3 KiB
Python
212 lines
7.3 KiB
Python
"""
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Experimental spectrum container.
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Stores measured detector spectra with metadata, uncertainties,
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and calibration information.
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"""
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from __future__ import annotations
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from dataclasses import dataclass, field
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from typing import TYPE_CHECKING, Optional
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if TYPE_CHECKING:
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from exp_data.calibration import CalibrationResult
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import numpy as np
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@dataclass
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class ExpSpectrum:
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"""Container for an experimental beta spectrum measurement.
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Parameters
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----------
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energies : np.ndarray
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Energy calibration values for each channel (keV), shape (N_channels,).
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counts : np.ndarray
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Raw counts per channel, shape (N_channels,).
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errors : np.ndarray, optional
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Statistical uncertainties per channel. Defaults to sqrt(counts).
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metadata : dict, optional
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Arbitrary metadata (source, run ID, date, etc.).
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dead_time : float, optional
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Dead time fraction (0.0 to 1.0).
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live_time : float, optional
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Live acquisition time in seconds.
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source : str, optional
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Radioactive source identifier.
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run_id : str, optional
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Unique run identifier.
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date : str, optional
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Measurement date (ISO format).
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"""
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energies: np.ndarray
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counts: np.ndarray
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errors: Optional[np.ndarray] = None
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metadata: dict = field(default_factory=dict)
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dead_time: float = 0.0
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live_time: Optional[float] = None
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source: Optional[str] = None
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run_id: Optional[str] = None
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date: Optional[str] = None
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def __post_init__(self) -> None:
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"""Validate and compute default errors."""
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self.energies = np.asarray(self.energies, dtype=np.float64)
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self.counts = np.asarray(self.counts, dtype=np.float64)
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assert self.energies.shape == self.counts.shape, (
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f"Energies ({self.energies.shape}) and counts ({self.counts.shape}) "
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"must have the same shape"
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)
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assert np.all(self.energies >= 0), "Energies must be non-negative"
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# Difference spectra (cumulative subtraction) can have negative counts
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# in channels where the true count is zero and Poisson noise causes
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# the earlier cumulative to slightly exceed the later one.
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# This is normal and expected — errors propagate correctly.
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if self.errors is None:
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# Poisson statistics: σ = √N for positive counts
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pos_mask = self.counts >= 0
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errors = np.zeros_like(self.counts)
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errors[pos_mask] = np.sqrt(self.counts[pos_mask])
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neg_mask = ~pos_mask
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if neg_mask.any():
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errors[neg_mask] = np.sqrt(np.abs(self.counts[neg_mask]))
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self.errors = errors
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else:
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self.errors = np.asarray(self.errors, dtype=np.float64)
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assert self.errors.shape == self.counts.shape
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@property
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def n_channels(self) -> int:
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"""Number of energy channels."""
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return len(self.energies)
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@property
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def energy_range(self) -> tuple[float, float]:
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"""(min_energy_keV, max_energy_keV)."""
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return (float(self.energies[0]), float(self.energies[-1]))
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@property
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def total_counts(self) -> float:
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"""Total counts in the spectrum."""
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return float(np.sum(self.counts))
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@property
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def live_time_corrected_rate(self) -> Optional[float]:
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"""Count rate corrected for dead time, in counts per second."""
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if self.live_time is None or self.live_time <= 0:
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return None
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live_seconds = self.live_time * (1.0 - self.dead_time)
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return self.total_counts / live_seconds
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def normalize(self) -> np.ndarray:
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"""Return spectrum normalized to unit area."""
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integral = np.trapezoid(self.counts, self.energies)
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if integral > 0:
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return self.counts / integral
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return self.counts.copy()
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def apply_dead_time_correction(self) -> ExpSpectrum:
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"""Return a new spectrum corrected for dead time.
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Correction: N_true = N_measured / (1 - τ), where τ is dead time fraction.
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"""
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if self.dead_time <= 0 or self.dead_time >= 1.0:
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return ExpSpectrum(
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energies=self.energies.copy(),
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counts=self.counts.copy(),
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errors=self.errors.copy(),
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metadata=self.metadata.copy(),
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dead_time=self.dead_time,
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live_time=self.live_time,
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source=self.source,
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run_id=self.run_id,
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date=self.date,
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)
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corrected_counts = self.counts / (1.0 - self.dead_time)
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corrected_errors = self.errors / (1.0 - self.dead_time)
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return ExpSpectrum(
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energies=self.energies.copy(),
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counts=corrected_counts,
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errors=corrected_errors,
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metadata=self.metadata.copy(),
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dead_time=0.0, # Corrected
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live_time=self.live_time,
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source=self.source,
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run_id=self.run_id,
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date=self.date,
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)
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def apply_calibration(self, calibration: "CalibrationResult") -> ExpSpectrum:
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"""Return a new spectrum with energies recalibrated via the given CalibrationResult.
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The calibration polynomial is applied to the current energy axis:
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calibrated_energies = calibration(channel_indices).
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Parameters
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----------
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calibration : CalibrationResult
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A CalibrationResult from EnergyCalibrator (e.g., from Am-241 peak detection).
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Returns
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-------
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ExpSpectrum
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New ExpSpectrum with recalibrated energies, all other fields preserved.
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"""
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calibrated_energies = calibration(self.energies)
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return ExpSpectrum(
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energies=calibrated_energies,
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counts=self.counts.copy(),
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errors=self.errors.copy(),
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metadata={
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**self.metadata,
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"calibration": {
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"type": "linear" if calibration.order == 1 else "quadratic",
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"coefficients": calibration.coefficients.tolist(),
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"chi2_per_dof": calibration.chi2_per_dof,
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"n_points": calibration.n_points,
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},
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},
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dead_time=self.dead_time,
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live_time=self.live_time,
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source=self.source,
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run_id=self.run_id,
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date=self.date,
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)
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def to_dict(self) -> dict:
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"""Serialize to dictionary."""
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return {
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"energies": self.energies.tolist(),
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"counts": self.counts.tolist(),
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"errors": self.errors.tolist(),
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"metadata": self.metadata,
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"dead_time": self.dead_time,
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"live_time": self.live_time,
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"source": self.source,
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"run_id": self.run_id,
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"date": self.date,
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}
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@classmethod
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def from_dict(cls, data: dict) -> ExpSpectrum:
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"""Deserialize from dictionary."""
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return cls(
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energies=np.array(data["energies"], dtype=np.float64),
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counts=np.array(data["counts"], dtype=np.float64),
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errors=np.array(data["errors"], dtype=np.float64),
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metadata=data.get("metadata", {}),
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dead_time=data.get("dead_time", 0.0),
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live_time=data.get("live_time"),
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source=data.get("source"),
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run_id=data.get("run_id"),
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date=data.get("date"),
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)
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