docs(aerotech): measured timing and positioning of the default series (scans 8486-8494)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M8zoDzDfsCTY2o5bT3J7Wv

docs/user/saxs/aerotech_stages/aerotech_stages.md

@@ -72,6 +72,7 @@ scans.aerotech_cont_grid(
 | `relative` | `True`: positions are offsets from the current X / Y position, and both axes return there after the scan |
 | `trigger_source` | `"ddg"` (default, beamline timing) |
 | `settle_time` | constant velocity time before the first exposure of a line, default 0.15 s (leave it) |
+| `minimal_run_up` | `True`: run-up only the acceleration distance (at least 10 um), no settling. Faster lines, but the exposures are less evenly spaced; use the captured positions. Default `False` |
 
 The number of points per line is `ceil(|fast_end - fast_start| / fast_step_size) + 1`,
 the number of lines `ceil(|stepper_stop - stepper_start| / stepper_step_size) + 1`.
@@ -144,9 +145,38 @@ centres from the nominal cells, backward minus forward offset, and the line time
 
 ## Timing and positioning
 
-!!! note "Results pending"
-    The measured values of the test series of 2026-10-29 are added here once the
-    series is complete.
+Measured 2026-10-29 (scans 8486-8494, default run-up, PandABox as trigger, readout
+0.2 ms, X acceleration 500 mm/s^2). Positions in um; "rms" is the scatter of the
+measured exposure centres around the nominal cells (forward and backward lines
+alike), "bwd - fwd" the offset between neighbouring lines with its slope along X
+and its peak-to-peak over the line.
+
+| Field of view (mm) | Step / exposure (speed) | Points x lines | rms | bwd - fwd | slope (um/mm) | peak-to-peak | Line period | Exposure per line | Positioning overhead per line | Scan time | Estimate with uneven positions (line, scan) |
+|---|---|---|---|---|---|---|---|---|---|---|---|
+| 0.8 x 1.2 | 100 um / 5 ms (20 mm/s) | 9 x 13 | 2.9 | +1.2 | +3.4 | 11.4 | 0.79 s | 0.04 s | 0.74 s (94 %) | 0.2 min | 0.45 s, 0.1 min |
+| 0.8 x 1.2 | 40 um / 20 ms (2 mm/s) | 21 x 31 | 1.0 | +3.6 | +0.2 | 2.9 | 1.03 s | 0.42 s | 0.61 s (59 %) | 0.6 min | 0.73 s, 0.4 min |
+| 0.8 x 1.2 | 10 um / 20 ms (0.5 mm/s) | 81 x 121 | 0.2 | +0.1 | 0.0 | 0.8 | 2.21 s | 1.62 s | 0.59 s (27 %) | 4.5 min | 1.95 s, 3.9 min |
+| 2 x 2 | 100 um / 5 ms (20 mm/s) | 21 x 21 | 5.6 | +2.3 | +0.2 | 25.6 | 0.83 s | 0.10 s | 0.72 s (87 %) | 0.4 min | 0.49 s, 0.2 min |
+| 2 x 2 | 40 um / 20 ms (2 mm/s) | 51 x 51 | 0.6 | +2.8 | 0.0 | 2.4 | 1.64 s | 1.02 s | 0.62 s (38 %) | 1.5 min | 1.34 s, 1.1 min |
+| 1 x 1 | 10 um / 20 ms (0.5 mm/s) | 101 x 101 | 0.2 | 0.0 | 0.0 | 0.8 | 2.61 s | 2.02 s | 0.59 s (23 %) | 4.5 min | 2.35 s, 4.0 min |
+| 3.5 x 3.0 | 100 um / 5 ms (20 mm/s) | 36 x 31 | 5.7 | +0.8 | +0.1 | 30.6 | 0.91 s | 0.18 s | 0.73 s (80 %) | 0.6 min | 0.57 s, 0.3 min |
+| 3.5 x 3.0 | 40 um / 20 ms (2 mm/s) | 89 x 76 | 0.5 | +2.8 | 0.0 | 2.9 | 2.40 s | 1.78 s | 0.62 s (26 %) | 3.1 min | 2.10 s, 2.7 min |
+| 3.5 x 3.0 | 10 um / 20 ms (0.5 mm/s) | 351 x 301 | 0.1 | -0.7 | 0.0 | 0.9 | 7.75 s | 7.02 s | 0.73 s (9 %) | 38.9 min | 7.49 s, 37.6 min |
+
+- **Positioning:** at 0.5 and 2 mm/s the exposure centres are within about 1 um
+  rms of the nominal cells, and the snake is symmetric (no slope). A constant
+  backward minus forward offset of up to ~4 um remains; it only shifts the field of
+  view. At 20 mm/s an oscillation of X after the acceleration ramp reaches into the
+  line: up to 25-30 um peak-to-peak on the larger fields. That is small compared with
+  the 100 um cells of these quick scans, but above the 20 um resolution target.
+- **Overhead:** about 0.6-0.75 s per line at every speed: run-up and run-out,
+  turnaround, the Y step (during the run-out of X), and the readout of the captured
+  positions (0.03-0.3 s, growing with the points per line). It dominates the quick
+  scans (80-94 % at 20 mm/s) and is small for the long high resolution lines.
+- **Uneven positions:** the last column is an estimate, not a measurement: the line
+  period minus the run-up and run-out that could be saved if the frames did not have
+  to sit on an even grid (see below). It will be replaced by measured values of the
+  same scans with `minimal_run_up=True`.
 
 The target resolution is about 20 um; the positioning accuracy should be well below
 that. Columns of the result table: