Motors and controlled axes¶
Motors are grouped by function. Each row is a logical axis on the beamline: position, angle, energy, aperture, or a derived setpoint. Values are in millimeters, degrees, electron volts, or dimensionless as noted in the beamline reference.
Sample positioning¶
| Motor | Purpose |
|---|---|
| Sample X | Along rotation axis; scans the plate through the beam along the goniometer axis |
| Sample Y | Perpendicular to beam at Sample Theta = 0; lateral offset of the illuminated spot |
| Sample Z | Normal to plate; height and (when tilted) coupling to sample–detector distance |
| Sample Theta | Primary sample tilt; grazing vs normal incidence |
| Sample Azimuthal Rotation | In-plane rotation of the sample about the surface normal |
| Sample Y Scaled | Derived or scaled Y used in specific scan recipes |
| Sample Number | Logical sample index for bookkeeping (not a mechanical axis) |
Detector arm and reflectivity¶
| Motor | Purpose |
|---|---|
| CCD Theta | Detector arm angle in the scattering plane |
| CCD X | Lateral detector position (same line as Sample X) |
| CCD Y | Camera length / sample–detector distance |
| Pollux CCD X, Pollux CCD Y | Alternate staging for Pollux detector configuration |
| T-2T | Coupled θ–2θ motion for specular reflectivity |
| Beam Stop | Beamstop position to block direct beam on the area detector (CMOS) |
Energy and monochromator (M101)¶
| Motor | Purpose |
|---|---|
| Beamline Energy | Commanded photon energy at the experiment |
| Beamline Energy Goal | Target energy for ramped or stepped energy scans |
| Mono Energy | Monochromator internal energy setpoint |
| Mono 101 Grating | Grating choice for energy range and resolution |
| Mono 101 Vessel | Monochromator vessel translation |
| M101 Feedback | Closed-loop energy stabilization |
| M101 Horizontal Deflection, M101 Vertical Deflection | Fine steering at the monochromator |
EPU (undulator)¶
| Motor | Purpose |
|---|---|
| EPU Gap | Undulator gap; sets fundamental and flux |
| EPU Z | Longitudinal undulator position |
| EPU Polarization | Polarization mode (circular vs linear S vs P, etc.) |
Mirrors (M103, M121)¶
| Motor | Purpose |
|---|---|
| M103 Yaw, M103 Bend Up, M103 Bend Down | Mirror pointing and curvature for focus and steering |
| M121 Translation | Secondary mirror translation |
Entrance and exit slits¶
| Motor | Purpose |
|---|---|
| Entrance Slit Width (and variants) | Horizontal acceptance before dispersion |
| Exit Slit Top/Bottom/Left/Right | Blade positions defining the beam at monochromator exit |
| Horizontal/Vertical Exit Slit Size, Position | Composite horizontal and vertical exit slit controls |
| Horizontal/Vertical Slit Position, Size | Additional slit axes where configured |
JJ scatter slits (upstream, middle, in-chamber)¶
For each of the three stations: Vert Trans, Horz Trans, Vert Aperture, Horz Aperture define centering and aperture in vertical and horizontal directions.
Higher-order suppressor and diagnostics¶
| Motor | Purpose |
|---|---|
| Higher Order Suppressor | Four-bounce harmonic rejection mirror position |
| Diag 106 | Named diagnostic stage (beam diagnostics path) |
Shutters¶
| Motor | Purpose |
|---|---|
| PiezoShutter Trans | Fast piezo shutter translation |
| PZT Shutter | Piezo shutter drive or encoded state |
Environment and sample environment¶
| Motor | Purpose |
|---|---|
| Temperature Controller | Hot stage setpoint (often in K with calibration to °C) |
| Coolstage | Cryogenic stage temperature control |
| Camera Temp Setpoint | Camera cooling setpoint (legacy name; CMOS stack may differ from old CCD setpoints) |
Camera and ROI¶
| Motor | Purpose |
|---|---|
| CCD Camera Shutter Inhibit, CCD Shutter Control | Software or hardware shutter interlock and drive |
| Camera ROI X/Y/Width/Height | Region of interest on the sensor |
| Camera ROI X Bin, Camera ROI Y Bin | Binning for speed or SNR |
Fine positioning and outputs¶
| Motor | Purpose |
|---|---|
| Piezo Vertical, Piezo Horiz | Piezo fine translation of sample or stage |
| OSP Adjustment | Optical sample position trim |
| AO 0, AO 1 | General analog outputs (often auxiliary drives) |
Multi-channel scaler (MCS)¶
MCS_axis0 … MCS_axis4 are logical axes tied to scaler hardware used in stepped or multi-channel acquisition modes.
Additional sample rotations¶
SampleRot0 … SampleRot4 are extra rotation axes for multi-axis sample manipulators.
Not every scan uses every axis; experimental plans should list only the motors that move for a given measurement and respect shutter and detector limits before large moves.