What to do in case of trouble !?!

Getting started: Standard SPEC commands

Like many other beamlines at ESRF our data acquisition system is SPEC (onsite only link). The best starting point to learn about SPEC at the ESRF is the BLISS documentation page (onsite only link). We list a number of important SPEC commands to get you started immediately:

  • mv <motor> <position> - move motor to the specified position.
  • mvr <motor> <distance> - move motor relatively by distance.
  • ascan <motor> <start> <end> <no steps> <time per step> - perform an absolute scan on the motor.
  • dscan <motor> <start> <end> <no steps> <time per step> - perform a relative scan on the motor around current value.
  • ct [time] - count for one second (default) or specified time (optional).
  • wm <motor> - where is motor.

Beamline specific commands

On top of the standard SPEC package, we have a number of beamline specific macros. Most useful are described here:

  • id26newfile <file_name> - open new data file (replaces newfile which should not be used).
  • id26cd -  elegant way of changing directory
  • id26idopen / idclose - open / close Front-End.
  • shopen / shclose - open / close experimental hutch shutter.
  • fshopen / fshclose - open / close fast shutter in experimental hutch.
  • fson <time> / fsoff - activate / desactivate automatic automatic fast shutter (shutter opens only during acquisition), time defines opening delay in miliseconds (suggested value <time> = 50).
  • gscan_on / gscan_off - activate / desactivate energy and undulator gap coupling, i.e. undulator gap is following any energy movement, scan etc.
  • id26mode - interactive menu to check and switch software features, hardware controlers and beamline operation mode (experiment or alignment).
  • rc [counter] - rocking curve scan to align second mono crystal with respect to the first one (default counter is I00).
  • id26mcce - automatic setting of the optimum range (and gain) of the counter (electrometer amplifier).
  • mccerange, mccegain, mccepolarity - manual setting of the range, gain and polarity of the counter (electrometer amplifier).
  • auto_offsets - determination of the counter offsets. Required after each manual change of the counter perameter.
  • ascan energy <start> <end> <no points> <time per point> - step-by-step monochromator energy scan in short range. Energy is given in keV. Time per point in seconds. Use gscan_on/gscan_off before to define if undulator gap should follow / not follow the energy change.
  • kscan energy <edge energy> <time per point> - step-by-step energy scan with equall k spacing of the points acquired behind the edge. Time per point in seconds. Use kscan_setup to define additional parameters. Do not forget to use gscan_on before.
  • fscan2 <start> <end> <time per scan> <energy interval> [no repetitions] [number of intervals in profile]- continous monochromator energy scan. If GSCAN_ON = 1 the undulator will be moved (linked scan). Use gscan_on/gscan_off commands to link/unlink undulator. Start and end energy are given in keV. Time per scan in seconds. One repetition by default.

The following two commands fscan and qscan invoke the fscan2 command:

  • fscan <start> <end> <no points> <time per point> [emission energy] [number of repetitions] - continous monochromator energy scan in short range. with constant undulator gap position. Start, end and emission energy (optional) are given in keV. Time per point in seconds. One repetition by default.
  • qscan <start> <end> <no points> <time per point> [emission energy] [number of repetitions] - continous monochromator energy scan in long range with coupled mono and undulator gap position. Start, end and emission energy (optional) are given in keV. Time per point in seconds. One repetition by default.
  • xescan <start> <end> <no points> <time per point> [excitation energy] [number of repetitions] - step-by-step X-ray emission energy scan. Start, end and excitation (monochromator) energy (optional) are given in keV. Time per point in seconds. One repetition by default.

Global variables and experimental scans

Beamline specific scans (fscan, qscan, xescan) and experimental scans (described below) use following global variables (flags) to controll advanced options like:

  • RCYESNO - if different than zero, rocking curve will be performed before each scan.
  • OFFYESNO - if different than zerooff, counter offsets will be measured before each scan.
  • BEAMCHECK - if value different than zero, scan will not be started if at least one of the conditions happen: either time to the next refill is to short or ring current dropped below 5mA (beam lost criterium) or synchrotron is not in delivery mode.
  • DET_SLIT - opening of the slit in front of the Avalanche Photodiode (determines energy resolution of the emission scans).

 

  • moveabove - move energy above the absorption edge, defined in keV and stored in global variable ENERGY_EXCITE_ABOVE.
  • xanes <scanning time> [repetitions] [emission energy] - continous scan over short energy range (absorption edge). Start, end and energy step are defined in keV and stored in global the variables XANES_START, XANES_END and XANES_INT. Scanning time is given in seconds per entire scan. Emission energy is given in keV (optional).
  • pre <scanning time> [repetitions] [emission energy] - continous scan over very short energy range (pre-edge). Start, end and energy step are defined in keV and stored in the global variables PRE_START, PRE_END and PRE_INT. Scanning time is given in seconds per entire scan. Emission energy is given in keV (optional).
  • exafs <scanning time> [repetitions] [emission energy] - continous scan over long energy range (extended structure). Start, end and energy step are defined in keV and stored in the global variables XANES_START, XANES_END and XANES_INT. Scanning time is given in seconds per entire scan. Emission energy is given in keV (optional).
  • xesmain <time per point> [repetitions] [excitation energy] - step-by-step scan of emission energy over main line region. Start, end and energy step are defined in keV and stored in the global variables KB_MAIN_START, KB_MAIN_END and KB_MAIN_INT. Scanning time is given in seconds per energy point. Excitation (mono) energy is given in keV (optional).
  • xessat <time per point> [repetitions] [excitation energy] - step-by-step scan of emission energy over satelite lines region. Start, end and energy step are defined in keV and stored in the global variables KB_SAT_START, KB_SAT_END and KB_SAT_INT. Scanning time is given in seconds per energy point. Excitation (mono) energy is given in keV (optional).
  • rixs <scanning time per spectrum> [repetitions] - 2D RIXS plane. Set of continous scans of mono energy, performed at increasing values of emission energy. Start, end and energy steps are defined in keV and stored in the global variables RIXS_XAS_START, RIXS_XAS_END and RIXS_XAS_INT as well as in RIXS_XES_START, RIXS_XES_END and RIXS_XES_INT, for absorption scans and emission energy positions, respectively. Scanning time is given in seconds per XAS spectrum.
  • rixs_et <scanning time per point> [repetitions] - 2D RIXS plane. Set of continous scans of mono energy, performed at increasing values of emission energy. Start, end and energy steps are defined in keV and stored in the global variables RIXS_XAS_START, RIXS_XAS_END and RIXS_XAS_INT as well as in RIXS_XES_START, RIXS_XES_END and RIXS_XES_INT, for absorption scans and emission energy positions, respectively. Scanning time is given in seconds per XAS spectrum.
  •  
  • scansx <emission energy> - macro to align sample with respect to the beam in horizontal direction. Emission energy given in keV.
  • scansz <emission energy> - macro to align sample with respect to the beam in vertical direction. Emission energy given in keV.
  • scansyy <emission energy> - macro to align sample with respect to the emission spectrometer. Emission energy given in keV.

Data review on the workstation

SPEC produces datafiles that consist of a alternation of scan headers and data in columns. There are several commands to allow data visualisation in SPEC. E.g. data from SPEC files can be displayed directly on the workstation using the cplot package.

  • plotselect <counter> - choose the counter that is displayed in the real time or splot spectrum window during standard SPEC scans. For data collected in continous mode, the equivalent command is zapplotselect.
  • cplot <scannumber> <x-col-number> <ycol-number> - plots in a new window. For each of the three parameters you can use -1, -2, ... to indicate the last, the last but one, etc.
  • pplot <scannumber> <x-col-number> <ycol-number > - produces the same plot on the beamline printer.
  • cpsetup - change the appearance of your cplot 's.

An alternative for using cplot is the use of NEWPLOT (onsite only link). Type newplot

at the Unix prompt and the rest is self- explanatory.

Data transfer to PC:

Strictly spoken there is no need to transfer data to PC. The data disk is mounted as a network drive at all the beamline Windows PC's (mount point \\bldata\id26\) and is also accessible from any unix machine under /data/id26/

. Nevertheless it is always recommended to make a copy of the SPEC datafiles to the local directory, especially if you plan to perform any on-line data analysis.

More commands

  • lsdef- list the macros currently defined.
  • h - gives the help associated to a defined macro.
  • <variable> = <value> - assign value to the global variable.
  • p <variable> - print value of the global variable.
  • wa - where are all my motors.
  • wmono - where are all the monochromator related motors.
  • wid - where are all the insertion devices motors (gaps and tapers).
  • wtab - where are all the tables.
  • whex - where are all the hexapodes.
  • wdet - where are the detector related motors.
  • wslits - where are beamline slits.
  • timescan - perform a timescan.
  • ^C (control-C) - abort an action (scan).
  • reconfig - reinitialise hardware, device servers, macro definitions, etc..
  • def <name> { .... } - write your own macro.