On frames taken with the shutter closed the pixels scatter about zero, and
poisson_deficit_sigma read a pooled sum below zero as a deficit that grows with
how far below it is. The scattered dark pixels then passed the 6-sigma test,
were bridged into one piece and filled: on rounded dark noise of 0.35 photon
the live stills pre-pass masked 70 % of a JUNGFRAU 8M as beam-stop shadow, and
the real frames that followed the closed shutter were analysed under that mask
(6 % indexed instead of 69 %). The observed count is now taken as at least zero,
on the host and on the device alike; a shadowed pixel still reaches
sqrt(2 * expected), so a real stop on a measurable background is found as before.
Replay of a serial run: mask, beam centre, distance and indexed images are
unchanged on the beam-on frames; dark frames with the detector's own negative
tail mirrored find no shadow (was 0.6 % of the detector), 0.35-photon dark
noise 1.8 % (was 70 %), and the frames after 200 such dark frames index as
after 200 empty ones.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UqXYdJKPUFLoeAchjzv3x4
leonarski_fandClaude Opus 5.5
8d7cf18277