VAC - Shaping Carbon Rods with a Manual Shaping tool

Created by Karen Darley, Modified on Wed, 22 May at 1:42 PM by Kathleen Patrick


Indicator on thumb screw indicates approximately 1mm diameter.

  1. Break carbon rod about 50mm - 75mm long.
  2. Insert flat end into the hole in the base of the carbon rod sharpener.
  3. Gently push the rod up into the cutter while rotating it in a clockwise direction. Hold the carbon rod sharpener so that any carbon dust falls into a waste container.

The formed tip should range from 0.4mm to 2mm in length to give the approximate film thickness shown in the table below.

It is often helpful to use a paper or porcelain indicator near the specimen. Approximate grey scale is indicated in the last column of the table.


IF:M = mass evaporated W = mass per unit areaW=M
4o D2

D = distance to specimenW= and tt p
M

t = thickness (of carbon)p = density (of carbon)=V=4o D2p or 2l

r = radius of carbon rod l = length of carbon rod v = volume of carbon evaporatedM=Vp and M = or 2 1p


t=or 2.1 = r2.1


4or2 1


Using the carbon rod sharpener as set, r = 0.5mmFor convenience, D = 100mm (with added block or platform) and the following table can be used directly.


1t (approximate)Indication
0.4mm2.5nmVery light
0.6mm3.8nmLight
0.8mm5nmMedium
1.0mm6.2nmMedium-dark
1.5mm9.5nmDark
2.0mm12.5nmVery dark


(Refer to electron microscopy textbooks by Hall, Kay, Pease and others.)


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