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ENGINEERING TRIPOS PART IIA - 2012/2013

Project SG1 - Atomic Force Microscope

Leader: Dr J Goncalves email: jmg77

Project Type: Standard
Project Category: Design
Prerequisites: 3F1 and 3F2 useful
Timing: Thursdays 9-11am plus afternoons and Mondays 11-1pm

Capacity: maximum of 8 students

SUMMARY

An Atomic Force Microscope (AFM) is a fairly new instrument in the area of Scanning Probe Microscopy (SPM) that is capable of imaging with extremely high resolution. It can resolve single DNA strands, measure nano-Newtons and determine friction coefficients of microscopic materials.

In this project students will work with a custom-made AFM with the goal of imaging small single-celled organisms called Diatoms. There is a significant focus in this project on the modelling and control of a piezo-electric translation stage, which is used to take scans.

Scan of a single blood cell taken within the AFM

AIMS

To enable students to:

Understand the basic functioning of an Atomic Force Microsope
Develop models for a piezo-electric translation stage and design controllers to compensate for its natural resonance, while still providing a sufficiently fast and accurate response.
Image single-celled organisms called Diatoms and investigate various post-processing methods to improve the images.

FORMAT

Students will work in teams of two, with each pair sharing an AFM.

ACTIVITIES

Week 1: Familiarisation with the procedures of using the AFM. Compute and then measure the gain of the /optical lever/, which is the enabling technology of an AFM and which determines its resolution. Write first interim report.
Week 2: Collect experimental data from the AFM for modelling. Hand measurement of the resonant frequencies. Develop spectral and parametric linear models in Matlab. Write second interim report.
Weeks 3 and 4: Develop controllers in Matlab and implement on the AFM. Takes various scans. Investigate three post-processing techniques in Matlab that will improve the image quality. Write final report.

ASSESSMENT

Format: Submission Date - Marks

Interim report 1: Thursday 16 May 2013 - 15 marks

Interim report 2: Thursday 23 May 2013 - 15 marks

Final report: 4pm Thursday 6 June 2013 - 50 marks

Last updated: November 2012

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