FAQs

What is the maximum pressure I can achieve with the CryoDAC-ST and a given culet size?

(*) The Pmax values are only indicative. The maximum pressure achievable with a DAC is influenced by many others experimental parameters, like the gasket characteristics (material, thickness and hole size) or the pressure transmitting medium.

What is the working distance of the CryoDAC-ST fitted inside the ST-500 from Janis?

The ST-500 has an optical window with a thickness of approximately 1.6mm. Assuming the microscope objective can approach as close as 1mm from this window and the top of the DAC is positioned about 1mm below the optical window, the total working distance of the microscope should be at least 12mm to focus in the middle of the two diamond anvils of the DAC.

Why can’t I mount my CryoDAC-ST DAC on my ST-500?

The ST-500 has undergone design changes, particularly in how the sample mount or diamond anvil cell is attached. Previously, it was screwed onto the cold stage, but now it requires 4 screws for mounting.

To resolve this, check the type of attachment on your CryoDAC-ST DAC—whether it’s threaded or requires screws.

Why can’t I perform cryogenic loading with the CryoDAC-ST?

The issue is likely due to the piston of the cell falling under its own weight, closing the gap between the gasket and the upper anvil before you start loading argon or pouring nitrogen.

Here are some questions to help diagnose the problem:

1. How do you calibrate and measure the starting gap between the upper anvil and the gasket before putting the DAC into your loader?
2. After placing the CryoDAC-ST, are you sure this gap still exists?
3. After loading the argon, how much can you turn the two clamping screws?
4. Once the cell has been removed and warmed up, does the gap between the anvil and gasket seem closed?

To ensure the gap remains during setup, you can place a piece of thick paper between the bottom of the cell and the piston. The paper should be flexible enough and non-intrusive to support the piston’s weight and allow the clamping screws to close the cell when immersed in liquid N2.

Why can’t I achieve pressure in a reproducible way?

Using the preindented-drilled gasket supplied with your order:

• Align the mark/dot on the gasket with the alignment mark on the DAC.
• Rotate the gasket slightly to ensure it fits the facets marks and sits properly on the culet.
• Ensure the gasket is touching the culet without any gap (a common mistake is placing the gasket upside down, leaving a gap for the PTM to escape).
• Use a 4:1 Methanol- Ethanol mixture as the PTM. If still struggling, try a more viscous PTM and check if it stays in the hole or escapes.
• After closing the cell, observe under a microscope to ensure the PTM is still in the hole.
• Increase the pressure.

If using your own gasket:

• Make a mark on the gasket to align with the cell’s alignment mark.
• Follow the same steps as above.

Can I carry out electrical measurements with the CryoDAC-ST?

Yes, you can perform electrical resistivity measurements with the CryoDAC-ST. It is possible to connect electrical wires to the lower anvil of the cell (the one at the bottom of the cylinder). However, this anvil is located deep within the cylinder, making electrical connections in the limited space challenging. So, while it is feasible, it is not straightforward.