Loading and unloading a hex ring into Gatan Rotational Holder

 

This protocol is a supplement to the Gatan manual.

 

Materials: Gatan specimen holder (SH), Gatan loading stand, hex ring tool, stereomicroscope (SM), light source, Ross lens tissues, can of Dust-Off, curved forceps, straight forceps, hex ring/grid assemblies, 90mm diameter plastic Petri dish, the Gatan instruction manual.

 

Loading Procedure:

1. Position the Gatan loading stand under the stereomicroscope (SM) for viewing. Blow off any dust or debris in every part of the stand, especially the cradle clamping arm and knob (bottom screw) with the Dust-Off. Repeat this procedure any time dust or debris is visible and whenever a new grid is being loaded or unloaded. Look through the SM into the cradle clamping arm throughout the loading and unloading operation for debris and dust. This is critical since the Pioloform film will become easily damaged or contaminated if dust or debris falls upon it!

 

2. Line the bottom of the plastic Petri dish with a new Ross lens tissue. Place this dish partly under the loading area to catch any grid that may fall.

 

3. Place the specimen holder (SH) into the loading stand as diagrammed in the manual. Position the housing end of SH at one end of stand as diagrammed. Secure the center of the specimen arm with the barrel clamp. The cradle arm should be in the park/load area.

 

4. The hex ring/grid assembly either should be stored in a gelatin capsule or be sitting in the Teflon loading tray. Remove it from the gelatin capsule just by "pouring" it out onto the lens tissue lining the Petri dish. Flip it over, if necessary, with a clean forceps so that the hex ring faces up. If the grid/hex ring is on the Teflon tray, then, with clean curved forceps, carefully grasp it around its sides, see diagram: Then transfer it over to the lens tissue sheet but invert it so the hex ring side faces up and the tissue/grid faces down.

 

5. Next, carefully pick up the hex ring/grid with curved forceps, hex side up, and place it into the cradle of the specimen holder. If it does not seat properly, use one of the prongs of the forceps to position it.

 

6. Slide the cradle clamping arm over to the "load" position (see manual). Look through the SM while centering the clamping arm hole over the cradle area.

 

7. Continue to look through the SM and turn the cradle clamping knob, counterclockwise, up against the cradle. Do not over-tighten!

 

8. Look at the cradle clamping arm from a side view to check if the cradle is seated properly in the cradle clamping arm. Adjust, if necessary, by unscrewing the cradle clamping knob (turn knob clockwise) and straightening out the SH. Then re-tighten the cradle clamping knob.

 

9. Pick up the hex ring tool and wipe the hex end clean of any dust or debris with a clean lens tissue. Always examine the hex end under the SM for any residual dust or debris. Repeat this procedure every time it is used to contact the grid/ hex ring. Avoid touching the hex end of the tool with fingers or any contaminated surface.

 

10. Carefully position the hex ring tool, hex end down, into the cradle. Carefully turn the hex ring tool clockwise, just enough to screw the hex ring into the cradle. Do not over-tighten!

 

11. Then remove the hex ring tool and place it, hex side down, into the convenient hole in the loading stand for temporary storage.

 

12. Loosen the cradle clamping knob by turning clockwise.

 

13. Slide the cradle clamping arm over to "park" position.

 

14. Unlock the barrel clamp.

 

15. Remove the SH from loading stand.

 

16. Examine the cradle under SM to see that the grid/hex is seated properly. Return the SH back into the loading stand for any re-adjustments.

 

17. As a final check, flip the SH over to see if grid/hex might fall out. It should be secure in the cradle.

 

18. If everything is secure, then SH is ready to load into electron microscope.

 

Unloading Procedure:

1. To unload a grid/hex ring from SH, the reverse procedure is mainly followed. Place SH into loading stand and secure properly.

 

2. Check the cradle clamping arm for any dust. Use Dust-Off to blow away any dust or debris. Next, slide the cradle clamping arm over to the "load" position. Look through SM to carefully center clamping arm hole over the cradle. Tighten the cradle clamping knob by turning counterclockwise.

 

3. Insert the cleaned end of hex ring tool into the cradle and turn gently counterclockwise to unscrew the hex ring/grid. Remove the hex ring tool.

 

4. To get the grid/hex ring out of the SH, unscrew the cradle clamping knob by turning clockwise. Then slide the clamping arm over to the "park" position.

 

5. Remove the SH from the loading stand (remove the barrel clamp). Then slowly rotate the SH so that the grid/hex ring falls onto the plastic Petri dish. Store the grid/hex ring back into a gelatin capsule.

 

6. Either reload a new grid/hex ring or store the SH away.