Limits of Detection:Report Requirements
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Revision as of 14:32, 1 December 2011 by Steven Wasserman (Talk | contribs)
- Before you go to the lab, read the optical trapping lab manual and the the Atomic Force Microscopy lab manual
- Attend an optical trap lab session during the week of 11/28-12/3.
- Attend an AFM lab session during the week of 12/5-12/9.
- Submit your report in PDF format to Stellar before midnight on 12/13.
- Name the file: <lastname>DetectionLimitReport.pdf. (Substitute your surname for "<lastname>")
- The report should be answer-book style, like a problem set.
- Submit all the computer code (.m files) that you used in your analysis as a single, separate zip file to Stellar.
You will gather data as a group; however, reports must be individually authored. Everything in your report, including computer code, must be entirely your own work.
- Optical trap calibration
- What is the responsivity of the QPD in microns per Volt? Plot the linearized detector response versus the raw data for at least one power level.
- What is your estimate of the trap stiffness as a function of power as determined by the three different calibration methods (equipartition, PSD roll-off, and Stokes drag)? Plot your results.
- For the PSD method: plot a representative power spectrum and the corresponding model fit on the same set of axes.
- For the Stokes method: plot a representative displacement versus velocity dataset and the corresponding regression model on the same set of axes.
- Which method is superior? Explain why.
- What is the minimum detectable force as a function of power and bandwidth?
- AFM
- What is the stiffness of the cantilever you measured? Plot the spectrum you measured and the model fit on one set of axes.
- How does the stiffness compare to the value computed from the cantilever's material properties and from the Sader method?
- What is the smallest force you could measure using that cantiliver?
- How could you modify the cantilever design to measure smaller forces? What is the smallest force that could practically be detected using a silicon nitride cantilever?
- How does the minimum detectable force compare to typical forces in biological systems (e.g. antibody/antigen binding, DNA hybridization, interdomain forces in proteins, etc.)?