Cold Mounting

Owned by AS MX Wiki
Last updated: Jun 16, 2023
3 min read

This is a guide for using the ColdMountPro! system. For hand-mounting tricky samples which degrade quickly, the ColdMountPro! attaches to a beamline microscope and can cool the microscope slide down to -40°C under a flow of cold nitrogen gas. A shield flow of room temperature nitrogen prevents icing and fogging of the slide. The cold region is contained to a small area on the microscope, and so it is easy and safe for users to manipulate crystals using normal tools. The slide is cooled on both the top and bottom.

This system was designed and made by Dr Michael Gardiner (ANU). Please acknowledge him in your paper if this system was useful in collecting your data.

Considerations

  • Do your samples degrade quickly in ambient conditions due to desolvation or reaction with air?

  • What temperature do you need? What is the freezing point of any solvents present?

  • While dry nitrogen is used to provide the cold and shield flow, this is not a completely inert atmosphere. Consider available options for mounting highly reactive samples.

Start up

  1. STAFF ONLY. Ask a beamline scientist or operator to turn on the valve to supply the cold mount with nitrogen.

2. Turn on chiller, then the control box with the switches at the front. Wait for approx. 5 min to initialize (the green ‘cool’ light will turn on).

 

3. Set the temperature* with the set point buttons (SP1-4) or manually with the up and down arrows. Select ‘run’ to start cooling. You will need to wait about 10-15 min to reach temperature if cooling to the coldest temperature. The green ‘cool’ and ‘run’ indicators should be lit up if working correctly.

4. Use the microscope as normal to mount crystals.

 

*Temperature at the sample will be warmer than the setpoint. See graph for approximating sample temperature. Changing the flow rates of the cold or shield flow will change the sample temperature. If an accurate temperature is needed, ask MX staff for use of a thermocouple.

Shut down

  1. Turn of control box and then chiller. Wait for 5 min to purge the system.

  2. STAFF ONLY. Ask MX staff or operators to turn off the nitrogen valve.

 

Troubleshooting

The slide is icing or fogging up!

Turn up the shield flow slightly. Note that this will warm up the slide.

The sample is not cold enough!

Turn down the shield flow. Ask beamline staff to increase the flow of nitrogen.

The controller won’t start cooling!

You may have turned on the chiller and controller in the wrong order. Turn them off again and turn on first the chiller and then the controller. Make sure the green ‘cool’ light is illuminated on the chiller before selecting ‘run’ on the controller.