feat: add raw binary spectrum reader and data quality analysis
- exp_data/raw_reader.py: read binary MCA spectra (128-byte header,
int32 counts), subtract cumulative spectra, Am-241 calibration
- exp_data/spectrum.py: allow negative counts for difference spectra
- scripts/analyze_raw.py: analyze 236 individual runs from cumulative
data, compute rates and endpoint drift
- Am-241 calibration: E = -0.96 + 0.451 * ch (CAM1),
E = 0.75 + 0.442 * ch (CAM2)
- Results: stable rate ~2M counts/run, stable endpoint ~374 keV
(smeared Q-value), spike at runs 214-219 (acquisition glitch)
unzhakov
5f70e3a15a