Set up the microscope in scanning mode. Refer to your microscope manufacturer's user manual for details.
Within the Gatan Microscopy Suite® (GMS) software, go to the Spectrum Imaging or STEM SI technique, then open the palettes you require for the experiment:
The SI Acquisition and STEM SI palettes enable set up and control of your SI experiment on the SEM and TEM, respectively. If no STEM SI experiment is currently set up, the palette appears in a mode selection state. Brief descriptions of the dialog features are given below.
In some models of the Monarc™ system, more than one acquisition mode is available within the SI workflow. In the CL palette, select the Spectrum or ARCL mode to collect a (wavelength) spectroscopy SI or an angle-resolved SI, respectively.
The top section of the palette features a button for each available signal in the SI experiment (e.g., CL, EDS, EELS, and CBED) and an icon to allow simultaneous capture of other DigiScan signals (e.g., SE-BSE). For each signal selected, the appropriate acquisition palette automatically expands or collapses and may trigger requests to change the microscope state as necessary. At least one signal (in addition to the Scan button) needs to be selected, or the SI experiment cannot start.
Note: Some signals are mutually exclusive. Selecting such a signal will automatically deselect the other.
Use the palette's bottom section to set up the spatial coordinates of the SI. Pressing a mode button (2D Array, Line Scan, Multi-Point, and Time Series) will automatically assign a suitable survey image and create a default SI survey region of interest (ROI) marker on it. If no suitable image is available, a Preview type acquisition is automatically started and assigned.
After choosing your signal and mode, a new palette is available. The palette includes:
Note: The acquisition time estimate automatically updates when you change the dwell time.
The bottom parameters (boxed in portion of the image) dictate the specific modes of capture per the selection made in the STEM SI palette. The options available are dependent on the mode that was selected there; the options include:
2D Array
The size automatically updates if you change the SI survey ROI position on the active survey image. When you change the Width value, it automatically adjusts the sampling resolution while keeping the acquired region the same. A change in Height changes the aspect ratio and hence the acquired region of the SI while keeping the sampling resolution identical.
Note: The acquisition time estimate automatically updates when the size is changed.
Line Scan
The sampling resolution automatically updates when the size is changed. Step displays the current sampling resolution in calibrated units. The SI size in pixels updates automatically when the sampling resolution is changed, keeping the acquired scan length identical.
Multi-Point
The number of survey ROI point markers is updated accordingly.
Note: You need to specify at least 2 points before the SI acquisition can start.
Time Series
Note: You need to specify at least 2 repeats before the SI acquisition can start.
During these pauses, the signal controllers stop, and the beam control releases to the default. The acquisition is then in an idle state similar to a paused acquisition, but at the bottom of the STEM SI palette, it displays a countdown. At the end of the countdown acquisition, the next spectrum is automatically started.
If checked, it acquires spectra while it rapidly and repeatedly scans a specified area. The ROI rectangle represents the area in the survey image and the two fields below the checkbox define sampling for this area. Enter values to change the area size or use the up and down arrows to change the sampling density of the area.