Olympus BioLever mini Panduan Pengguna - Halaman 4

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Case 2: When adjusting light spot position on the photo detector of AFM sensor head, SUM

value indicating total incident light to the sensor, was small and rose to only 3 volts. Eight

volts can usually be expected with cantilever with a reflex metal coating.

Solution:

As far as we examined, most commercially available AFMs display a SUM value of 3

to 4 volts even in the light spot shines center of the cantilever. This is due to the small

size of the cantilever which is as large as the light spot.

Try to adjust the focus of the sensor optics again. The adjustment might improve the

SUM value. If possible, the adjustment should be done in the same environment as

that of measurements.

The chip is 0.3 mm thick. If you have used different type of cantilever chips before, for

instance with a chip thickness of 0.5 mm, the spot may be out of focus on the cantilever.

If possible, adjusting the focus of the spot in the focal depth direction might the

improve SUM value.

The position of the spot on the cantilever should be adjusted as shown in the diagram

left below.

If the spot is positioned at the extreme end of the cantilever, the laser may scatter,

thereby reducing the total incident light on the photo detector, leading to a small SUM

value.

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Case 3: The SUM value changes gradually with time.

Solution:

The spot position may have moved with time because of thermal drift in your AFM

equipment. After the equipment is switched-on, allow some time for thermal

equilibration and a stable instrument.

Case 4: I have used this tip to image a standard flat grating pattern. However, the images

has a high degree of curvature, with the center of the image appearing brighter (higher) and

sinking down at the edge of the image.

Solution:

With using AFM equipments with a sensor head supported by a tripod mechanism, a

cantilever chip-shoulder might contact to the sample surface before the cantilever itself

contacts. This is due to use of short cantilever in the AFM which the sensor head.

Avoid rotation of the chip substrate in your chip holder.

The cantilever chips should aligned straight in the

cantilever chip holder.

In clipping the chip, the chip should slide ahead a little

than usual to avoid contact of the holder to the sample.

If your chip holder uses L-shape wire for clipping a

chip, the corner of the wire may hang over the clipping

wire bar after repeat use.

Then, adjust the level of the AFM sensor head in the AFM and make the AFM sensor

head and scanner parallel. In this procedure, use of a small water-leveling bottle is

effective. It is important to minimize the tilt, especially in the transverse direction

across the cantilever axis.

A cantilever chip in a chip holder

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