Module 10: High & Ultra High Vacuum Gauges

Description: Provides fundamental information about gases necessary to understand vacuum device operation.

Length of Time: 4 hours

Topics:

1. Emission

a. Thermonic

b. Field

c. Secondary

2. Cold cathode ionization gauge

a. Electric field

b. Magnetic field

3. Hot cathode ionization gauge

a. Ion Gauge

b. Degassing

4. Electric field distribution

5. X-ray limit

 

Student Objectives:

Student will be able to:

1. List three methods of electron production: thermionic, field, and secondary.

For each of the following gauges: cold cathode ionization gauge and hot cathode ionization gauge;

2. Sketch the gauge.

3. Identify the components.

4. Explain the theory of operation.

5. State the operating pressure range for the gauge.

6. List the limiting factor(s) for high and low pressure limits for each gauge.

7. Given two different gases, compare the pumping speed for each gas.

8. Given a specific gas, select the type of pump that would produce the highest pumping speed.

 

References:

Chambers: Chapter 4 "Measurement of Pressure"

O’Hanlon: Chapter 5 "Pressure Gauges"

Varian: Chapter 5 "Gauges"