Superscan Scripting Niklas Dellby Nion Company (www.nion.com) What - - PowerPoint PPT Presentation

Superscan Scripting

Niklas Dellby Nion Company

(www.nion.com)

Nion Swift workshop, Oct 2018 What does the superscan actually do? And how do we control it?

The Scan Area

Nion Swift workshop, Oct 2018 The beam sits stationary in top left hand corner, usually waiting for AC sync (Frame sync) Then sits still for StationaryBlank pixels with no data collection. Then moves for RampedBlank pixels with no data collection Then moves and collects data for width pixels. Subsequent lines wait for AC Sync if Line synced Scan area -32768 to 32767 in X and Y

The Pixel Stepping

Nion Swift workshop, Oct 2018 Example is a 3uS Superscan Clock, and a roughly 4uS external clock. Input signal (blue) is digitized and integrated (Gray) Integral is transmitted on internal pixeltimer end Beam moves and integration starts on external clock rising edge External clock pulses before pixelend are ignored.

The External Clock

Nion Swift workshop, Oct 2018 Most Cameras can be made to emit an end of frame signal. CCD1010 CCD2020 Photonic Sciences/Gsense Kuro ProEM Set up camera to generate pulses, with the first pulse being the first frame collected. 2 or 3 cameras, need to select signals Ronchi Camera EELS Camera

PMT Switching Matrix

Nion Swift workshop, Oct 2018 3 inputs and 3 outputs Inputs are 5V(3.3V) Outputs are: Blanker, Post(LVDS) , GIB(5V) SS-blank out to Acq Ronchi-Aux EELS-EELS Dual EELS camera-uses 2

• boards. Then BP10 GIB out to

EELS on BP2

PMT Switching Matrix

Nion Swift workshop, Oct 2018 Get working in Dacwin, then copy mode numbers In Hexadecimal to BlankerMask Drives. Gib:0xAA=>BlankerMask2:170 Put in settings control

Scan Vectors: Scan

Nion Swift workshop, Oct 2018 Multiplying DAC’s scale and combine to give the desired scan and rotation. Exaggerated FL for clarity, we scan through Front principal plane-not Front focal plane Descan PrA is aligned with EELS dispersion direction

Scan Vectors:Tilt

Nion Swift workshop, Oct 2018 Tilt Scan is added to scan vectors to correct Coma, but also for precession scanning. Medium Mag imaging also uses angular scan.

Scan Vectors:Settings

Nion Swift workshop, Oct 2018 Standard scan mode is “Scan+Descan”,

• nly this and “Low Mag” are typically used.

Scan mode and vectors set in AS2 To only scan post-sample use No Prescan AR uses no descan Flyback time sets StaticBlanking and Ramped Blanking to half each Beam Lag shifts scan “16us” into the future

Scan Vectors:Low Mag

Nion Swift workshop, Oct 2018 Low Mag uses both scan dipole layers in unison, no descan and captures the beam with PL1

Precession Diffraction

Nion Swift workshop, Oct 2018 We want to scan the beam in a circle And integrate the signal over the beam path. Set camera to collect all the signal

• ver multiple frames

Blank beam using Superscan Blank Software overhead between section slows things down-but will get better

Precession Diffraction

Nion Swift workshop, Oct 2018 Set blanking to SSBlank Condensers to nanodiffraction Start collecting Ronchi frames Set up single line scan-see left Scan in angle No descan Change Rotation π/8, rescan 15 times Sum images

Summary

Nion Swift workshop, Oct 2018

There’s a lot of little things to set up right to get interesting acquisitions going, but once you know what you want it is only a few function calls.