CHESS-ID3A-FAST

#Useful spec commands:

spec.log for a given sample is saved in /nfs/chess/raw/[run cycle ID]/id3a/[userid-file ID]/[sample ID]

##Basic spec commands:

• ascan [motor] [start] [stop] [#steps] [count time] is an absolute position scan of [motor]
  • if aligning, use mbascan [motor] [start] [stop] [#steps] [count time] to automatically close garage door to protect far-field detectors
• dscan [motor] [relative start] [relative stop] [#steps] [count time] is a relative position scan of [motor]
  • if aligning, use mbdscan [motor] [start] [stop] [#steps] [count time] to automatically close garage door to protect far-field detectors
• d2scan does a dscan of 2 motors simultaneously
  • if aligning, use mbd2scan [motor] [start] [stop] [#steps] [count time] to automatically close garage door to protect far-field detectors
• umv [motor] [position] is an absolute move of [motor] to [position]
• umvr [motor] [relative position] is a relative move
• tw [motor] [step size] gives you a prompt to move [motor] by relative +/- [step size]. Within the prompt hit enter to do the move, type + or – to change directions, type a new step size to change step sizes; type anything else to exit tweak mode
• wm [motor] reports [motor]’s current position, and also displays [motor]’s limits
• we prints all motor positions
• ct [count time] counts for [count time] and displays the resulting ion chamber counts
• To change variable plotted on the y-axis in yellow spec graph: plotselect [counter] , then splot
• prdef [macro name] displays the definition of the macro, including the filename where it’s located
• qdo [macro name] recompiles a macro file
• newsample prompts you to define a new sample name

##Checking and setting the beam width and height:

• get_beam_width returns the width of the beam-defining slits (s0l, s0r) in mm
• get_beam_height returns the height of the beam-defining slits (s0t, s0b) in mm
• set_beam_width sets the width of the beam-defining slits
• set_beam_height sets the height of the beam-defining slits
• similar macros get_guard_width, etc exist to check or set the guard slits (s1t,b,l,r)

##Absorption foil utilities:

• insert_foil [1,2,3,4] inserts Sn (29.200 keV), Pr (41.991 keV), Tb (51.996 keV), Yb (61.332 keV)
• remove_foils removes all foils
• where_foils tells you what foil is currently in as well as the monochromator energy

##Fast shutter and garage door:

• opens opens the fast shutter
• closes closes the fast shutter
• open_garage_door opens the garage door (lead shield in front of the far-field detector)
• close_garage_door closes the garage door

##Attenuation:

• atten [thickness] inserts [thickness] mm of steel; range is 0-20 mm in 0.25 mm steps. NOTE: the fast shutter automatically closes when the attenuation is changed, so make sure to opens if you are e.g. watching the live view on the near-field camera or running line-up scans (dscan, etc)
• watt returns the current attenuator thickness

##RAMS2 loading:

The RAMS2 operates in displacement control by default. Load control is possible, but should be used with care and only if you have consulted with beamline staff first.

• mvr_screw [displacement] [block] [velocity] [acceleration] moves the screw head by [displacement] mm, at corresponding [velocity] and [acceleration]. Almost always set [block] = 1 to have mvr_screw block the spec terminal until motion is complete. [displacement] > 0 for tension, < 0 for compression. [velocity] and [acceleration] should be given as absolute values.
• wm_screw returns the current screw position in mm
• wm_force returns the current load cell reading in N
• mv_force [force in N] switches from displacement control to load control and moves to the specified force (units: N). It will hold at this force until another mv_force command, or until rams_force_off. Note: load control only works if the screw position is within a millimeter or so of 0 (the position it was at when the RAMS2 was last power cycled).
• rams_force_off exits force control and re-enters displacement control

##data acquisition: far-field

• sync_ff_on preps the far-field detector (Dexelas or GE) for data acquisition, moves the near-field detector out of the way, opens the garage door, and sets the attenuation to 8 mm steel (to prevent accidental damage to the far-field detector). should be preceded by sync_nf_off if the near-field detector has been in use.
• sync_ct [number of frames] [exposure time] [OPTIONAL: darkfield] opens the fast shutter, acquires [number of frames] frames each with exposure time [exposure time] (in s) on the far-field detector, then closes the fast shutter. If the optional flag darkfield is used, the garage door and fast shutter are closed before data acquisition, and the garage door is opened afterwards.
• slew_ome [ome start] [ome end] [number of frames] [exposure time] [OPTIONAL: darkfield] rotates RAMS2 ome from [ome start] to [ome end], acquiring [number of frames] with exposure time [exposure time] during rotation. The fast shutter is opened and closed at the beginning and end of data acquisition. If the optional flag darkfield is used, the garage door and fast shutter are closed before data acquisition, and the garage door is opened afterwards.
• sync_ff_off removes the far-field detector from data acquisition and closes the garage door.

##data acquisition: near-field

• sync_nf_on preps the near-field detector (Retiga or Manta) for data acquisition, moves the near-field detector into place, moves the near-field beamtop into place to block the direct beam, and sets the attenuation to 0 mm steel. should be preceded by sync_ff_off if the far-field detector has been in use.
• sync_tomo_on is identical to sync_nf_on, except that it moves the near-field beamtop out of the field of view.
• slew_ome [ome start] [ome end] [number of frames] [exposure time] [OPTIONAL: darkfield] rotates RAMS2 ome from [ome start] to [ome end], acquiring [number of frames] with exposure time [exposure time] during rotation. The fast shutter is opened and closed at the beginning and end of data acquisition. If the optional flag darkfield is used, the garage door and fast shutter are closed before data acquisition, and the garage door is opened afterwards.
• nf_stream_on starts a live stream of 1 s exposures on the near-field detector. Images are not saved.
• nf_stream_off stops the live stream. if nf_stream_on was used, nf_stream_off must be used prior to data acquisition or images will not be saved.
• sync_nf_off removes the near-field detector from data acquisition.