APIs for the Sader Method GCI
We have developed an API interface that lets you seamlessly use the Global Calibration Initiative directly on your AFM. This development is free to all AFM users.
At the moment we have a full implementation compatible with Asylum Research systems where you can effortlessly access and/or upload data to the GCI and access its worldwide database - while using the standard Thermal Tune of the Asylum AFM.
We have also provided examples in Python and Julia. These should allow you to add access to the GCI to most platforms. If you have requests for other languages or would like to contribute to this project please let us know.
Please email feedback (quoting version number and AFM type): email@example.com
We hope that this new development helps to facilitate the worldwide standardisation of AFM force measurements.
Using the API Interface for Asylum Research
Enter your username and password for the Sader Method GCI (sadermethod.org), and press Enter, to enable the GCI Panel.
Thermal frequency, quality factor and spring constant in the GCI Panel are taken directly from the Thermal Panel in the Asylum Research AFM Software.
Retract your cantilever at least 100 μm from the surface prior to taking a Thermal.
- First calibrate the spring constant using the Thermal Method.
- Tick the Enable checkbox next to Thermal Spring Constant.
- Select your Lever from the pull down menu and press ‘Upload & Calculate’.
- The frequency, quality factor and spring constant are merged with the GCI database. The Sader Method gives a new calculation of your spring constant and its uncertainty.
- Measure and fit a Thermal only (InvOLS not required).
- Ensure the Enable checkbox next to Thermal Spring Constant is NOT ticked.
- Select your Lever from the pull down menu and press ‘Calculate’.
- Only the frequency and quality factor are sent to the GCI. The Sader Method uses the existing database to calculate your spring constant and its uncertainty.
Approach 1 lets users contribute their data to the international database, and compares their calibration measurements to those of others - letting users help each other and providing a global reference point for AFM force measurements.
The Thermal spring constant is your locally calibrated value, whereas the Sader spring constant is standardised internationally. Check your measurements if there is a large difference between these values; see Reference (below).
- Request a lever: Users request cantilever models to be added to the GCI via this link.
- Register: Users register via this link.
- Status: Indicates if InvOLS is calibrated and whether Approach 1 or 2 is used.
NOTE: Take measurements of the fundamental flexural mode in air. The GCI reports the static normal spring constant at the imaging tip position.