During your session

Pixel size and camera set-up

It is worth thinking about how you want the microscope and camera to be configured in advance of your session. You can always discuss this with the staff setting up your session, but having one or two ideas will help speed it up.

Linear or counting

The DE-64 can run in two modes; linear or counting. Counting has a higher DQE but we have to hardware bin the camera by a factor of two. This means that for a given pixel size, a linear image is 4 times larger. So the trade-off is field of view vs. quality. Counting is also slower than linear.

Pixel size (or magification)

Small pixel sizes (high magnifications) are needed to achieve high resolution reconstructions. However, that doesn't mean the smallest pixel size is appropriate for every project. If your complex is sparse or large then the small field of view at high magnifications may not give you very many particles (also a reason to consider linear mode). Equally, if you expect the resolution of your final reconstruction to be limited by some other reason, then it does not make sense to use a very small pixel size. It would be better to collect more particles at a larger pixel size.

Common pixel sizes in linear
Magnification

Pixel size / Å

40,000x

1.499

50,000x

1.177

60,000x

0.997
Common pixel sizes in counting
MagnificationPixel size / Å
100,000x

1.209

120,000x

1.015

150,000x

0.829

200,000x

0.598

 


Session Timings

CRYO ARM 300 data collection sessions run for 48 or 72 hours. The user is only requested to be on site for the first working day of the session. An approximate session is outlined below, although this is dependent upon the requested microscope configuration and the specimen.

 

UK time24h time 
9.30am 09:30 Arrive at SCMI
9.30am - 10am 09:30 - 10:00 Load samples
10am - 12pm 10:00 - 12:00 Set up imaging conditions, screen grids, take test images
12pm - 1pm 12:00 - 13:00 Gain Reference (if required)
1pm - 2pm 13:00 - 14:00 Collect grid square montages
2pm - 3pm 14:00 - 15:00 Select targets for acquisition
3pm 15:00 Run session, set up data transfer. Adjust settings if necessary