USDA FOREST SERVICE, KISATCHIE NATIONAL FOREST, 2500 SHREVEPORT HIGHWAY, PINEVILLE, LOUISIANA 71360

66 -- ATOMIC FORCE MICROSCOPE SOL RFQ R8-6-97-17 POC Sheryl Roach, 318-473-7259 Sources being sought for providing one (1) Atomic Force Microscope which meets the specifications listed below. Companies who are able to provide a product meeting these specifications should respond to POC listed in this notice not later than June 25, 1997. 1. Digital feedback control for tip-sample separation. 2. In addition to contact and non-contact sampling modes, the scope must be expandable to image in tapping mode. Key factors which must be present for tapping mode include: A. Oscillated AFM probe B. AFM probe momentarily contacts specimen surface C. AFM probe lifts from the sample surface so that it does not contact the surface during translation to the next sampling point. This minimizes surface damage. Imaging in tapping mode allows true morphometric measurements while minimizing shear force, sample compression and stick-slip motion. This permits the measurement of many soft samples and those that interact with the tip by electrostatic or meniscus forces. 3. The system must be expandable to provide the ability to perform phase imaging (the oscillated probe contacts the sample surface, penetrating the adsorbed liquid layer such that the surface is imaged and lifts from the sample surface). As the topography image (changes in cantilever oscillation amplitude) is acquired and displayed, the data for the phase change are simultaneously acquired and displayed. 4. Simultaneous acquisition of a minimum of three channels of data. 5. The controller must provide independent 16-bit digital to analog converters (DAC's) per channel (x-, y-, and z-axis) and one each for scan size, scan pattern, and offset (for a total of 9 DAC's). 6. Real-time linearity correction must be performed via non-linear voltages to the piezoelectric scanner. The system must provide active, real-time scan linearization to better than 2% for all scan sizes and scan rates over the entire range of the scanner. 7. The system must provide a laser focus and tracking system that provides the means for the laser spot to follow the cantileverduring any X/Y motion of the scanner at any rate. This minimizes the effects of image bow, force variations of the full scan field and eliminates adverse effects due to limitations in cantilever size, shape, and texture. 8. The scanner must be piezoelectric, with a multi-part tube scanner with separate x-, y-, and z-segments. Materials for the segments are different and chosen for optimal sensitivity and linearity. The design also limits cross coupling between the x-, y-, and z-axes. 9. Must be expandable to perform lift mode, where topography is determined on a first pass over a scan line and a second parameter (which may not be related to topography such as magnetic field) is determined on the second pass. This allows parameters such as amplitude, phase, or frequency detection to be changed on the two passes. This allows for direct separation of topographic data from the information gathered on the second pass. 10. The noise level must be less than 0.5 Angstrom RMS in the vertical (z-) dimension in acoustic environment of 75db white noise, and less than 0.35 Angstrom in low vibration, low noise environments. Test conditions: surface tracing servo gain set to repeatedly resolve 10nm-scale texture on a polished silicon wafer surface at a scan size of 1 micron and scan rate of 2.5 Hz with acoustic and vibration isolation. This is with real-time linearity correction active, and all noise specifications obtained with real-time correction activated. 11. The system must have a vertical range of at least 6 microns. 12. The system will primarily be used to image biological samples. As such, the system must have the ability to be expanded to image in tapping mode while immersed in a liquid media. The system must demonstrate the ability to image the crystalline substructure of microfibrils of lignocellulosic fibers in our laboratory. 13. The scope must be able to conduct at least a 100 by 100 micron scan. 14. The system must demonstrate the ability to image down to atomic resolution within the confines of our laboratory.15. The system must be expandable such that it can collect force-modulation traces. 16. The system must be able to conduct post-image acquisition analysis while simultaneously collecting additional image data. Analysis algorithms must include surface roughness, surface area, fourier transforms, spectral analysis, and fractal anaylsis. (0157)

Loren Data Corp. http://www.ld.com (SYN# 0312 19970610\66-0011.SOL)