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Unformatted text preview: 2. What effect does each of the following changes have on the performance of a proportional counter? (a) The diameter of the anode wire is increased. (b) The pressure of the fill gas is increased. (c) The atomic number of the wall material is increased. Solution: (a) By increaging the diameter of the central anode wire, the electric field is decreaged near the wire surface. This reduces the multiplication factor of the avalanche mechanism and thus reduces the magnitude of the output pulses from the detector. (b) Increaging the gag pressure increages the density of gag atoms in the cham-ber. Consequently, more atoms are near the anode so that there is a slight increage in the avalanche multiplication effect. Also increaged gag pressure 8-1 July 24. 2002...
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This note was uploaded on 02/01/2010 for the course ECE 4130 taught by Professor Cady during the Spring '06 term at Cornell University (Engineering School).
- Spring '06