Flow Control

Start/Stop

Once the spectrum image (SI) acquisition parameters and any artifact corrections have been set up, hit the Capture button on the STEM-SI palette to start an acquisition. If you wish to update the survey image before proceeding with acquisition, right-click on it and select Restart scan from the context menu.

Once started, the SI acquisition routine will control the microscope beam, and the acquisition will begin. During acquisition, the Capture button will pulse in blue, indicating that an acquisition is active and that a subsequent click of this button will halt it. A new workspace is created and filled with a copy of the survey image and data containers for all acquired signals.

Note: During active SI acquisition, the spectrometers will not be available for single-spectrum acquisition.

If spatial drift correction is enabled, preliminary measurements will be performed. Depending on the preferences specified, visual feedback on the measurements may be provided.

Using the Visual Feedback provided, you can monitor how the acquisition is proceeding. Each SI will be displayed as a new image window, filling as the acquisition proceeds. Live spectra may also be shown or hidden as desired. If at any point you wish to halt the acquisition, click on the pulsing Capture button. When the acquisition is halted or completed, the beam control is returned to the Beam Safe Point if one has been set up, or alternatively, it is returned to the microscope.

Pause/Resume

During an SI acquisition, it may become necessary to perform a microscope adjustment that will temporarily degrade the data being collected by the spectrometer. At such times, you should pause the acquisition, adjust, and resume after conditions have stabilized. To pause the acquisition at any time, click the pulsing Capture button in the STEM-SI palette while simultaneously pressing the Alt key. The label of the Capture button changes to Resume.

When the acquisition is paused, the beam is either moved to the beam Safe Point if you have defined one, or otherwise, beam control is returned to the microscope. If the acquisition is paused and restarted, the software immediately carries out spatial drift corrections if Apply on Resume from Pause has been enabled before acquiring data from where it was before the pause.

To resume acquisition from the paused state, click on the Resume button. To stop acquisition from the paused state, click the Resume button while keeping the Alt key pressed simultaneously.

Note: Pausing is not available for hardware-synchronized acquisitions. On systems that, by default, use hardware-synchronized acquisition, you can force software synchronization via the Setup dialog.

After the acquisition

If the autosave functionality is enabled, all experimental data will be saved immediately using the current SI group saving options. If the close column values after the acquisition option are enabled, the microscope column valves are closed (on systems that support column valve access). You can use the (still) active survey image on the View workspace to immediately restart an identical or similar acquisition after adjusting survey ROIs and parameters.