Course detail

# Vacuum technology

Gas, vapour, pressure, Kinetic theory of gases. Volume processes and transport of gas, gas diffusion and gas viscosity. The gas transport through the vacuum pipes. The surface processes, adsorption, desorption. The pumping processes, The basic principles of the gas transport. Transport and getter pumps. Pressure measurement. Thermocouple Gauges, Pirani Gauges. Ion Gauges. The basic principles of vacuum equipment design. Technological processes in low pressure gases.

Learning outcomes of the course unit

Based on the verification of the student's knowledge and skills in seminars, laboratory work and in the written exam, after completing the course the student is able to:

Interpret the ideal gas laws: Boyle-Mariott, Gay-Lussac (Charles´s) and Dalton laws.
Derive and interpret the Equation of state of ideal gas.
Derive from the Equation of state numerical value of the Universal Gas Constant, Avogadro's Number and Boltzmann constant.
Derive from the Equation of state the relation between pressure, gas concentration and the temperature.
Define conditions for modeling the processes in gases using the Kinetic theory of gases.
Calculate the number of incident molecules per unit time per unit area.
Calculate the mean free path of particles in the gas and discuss its impact on the processes in vacuum.
Define and explain the Maxwell-Boltzmann velocity distribution of particles in the gas.
Calculate the mean velocity, root mean square velocity and most probable velocity of particles in a gas.
Describe and discuss the volume and transport phenomena in gas - particle diffusion, viscosity and thermal conductivity of gas.
Describe and discuss surface processes in vacuum - adsorption, desorption, formation of monomolecular and multi-molecular layers.
Define and explain the basic adsorption isotherms - Langmuir, Henry and BET isotherms.
Define vapor pressure and saturated vapor pressure.
Interpret Clausius-Clapeyron relation and August equation.
Discuss how the processes associated with the vapor pressure and saturated vapor pressure influence the vacuum devices and technological processes in vacuum.
Define resistance and conductivity of the vacuum pipe.
Define mechanisms of respective gas flow and calculate and measure the conductivity of a vacuum pipe for different types of the gas flow - turbulent gas flow, viscous flow, molecular flow and effusion flow.
Define nominal and effective pumping speed of the vacuum pump.
Define the continuity equation and interpret its meaning for pumping of vacuum equipments.
Describe the processes and mechanisms that are used for pumping of vacuum devices.
Describe and discuss the influence of vacuum leakage and desorption processes.
Calculate the ultimate pressure of vacuum equipment.
Calculate the required pumping speed pumps with regard to the arrangement of the apparatus.
Calculate the time of exhaustion to the desired pressure.
Measure the pumping speed of the pump using a constant pressure and constant volume methods.
Describe and explain the operation of transport pumps - rotary oil pump, Roots pump, turbomolecular pump, jet-ejector and an oil diffusion pump.
Describe and explain the operation of sorption pumps - titanium sublimation pump, diode ion pump, triode ion pump, cryopump and cryosorption pump.
Define and explain methods for measuring the vacuum-pressure.
Describe and explain the operation of Torricelli tube and U-tube.
Describe and explain the operation of thermal vacuum gauges – Piranni vacuum gauge and thermocouple vacuum gauge.
Describe and explain the operation of Penning ionization vacuum gauge including typical application areas.
Describe and explain the operation of triode vacuum gauge including typical application areas. Define design principles of vacuum equipments and facilities.
Design and build a simple vacuum apparatus.
Describe and discuss technological processes in a vacuum - vacuum drying, vacuum evaporation, sputtering technologies, dry etching technologies, thermal chemical vapor deposition and plasma enhanced chemical vapor deposition .

Prerequisites

The subject knowledge on the Bachelor´s degree level is requested.

Co-requisites

Not applicable.

Recommended optional programme components

Not applicable.

Roth A.: Vacuum Technology, 3rd ed., North-Holland, Amsterdam (1990) ISBN: 0-444-88010-0 (EN)
John F. O'Hanlon : “User's guide to vacuum technology”, 3rd ed., New Jersey, John Wiley, 2003. xviii,516p. ISBN : 0-471-27052-0 (EN)
Boušek J.: “Vacuum Technology”, printed lectures, 82 p, FEKT VUT v Brně, Brno (2004) (EN)

Planned learning activities and teaching methods

Teachning methods include mutually interlaced lectures, numerical exercises and practical laboratories. Course is taking advantage of e-learning (Moodle) system. Each student elaborates an individual project.

Assesment methods and criteria linked to learning outcomes

Laboratory practicum - 30 points; minimum 20 points.
Final exam – 70 points; minimum 30 points.

Language of instruction

English

Work placements

Not applicable.

Course curriculum

Gas, vapour, pressure, measurement units and their relation.
Basic principles and laws for the ideal gases. Boyle-Mariotte law, Gay-Lussac law. The state equation of the gas. Daltons law. Important constants.
Kinetic theory of gases - basic principles. Relation between pressure, concentration and temperature of gas. The mean free path of gas molecules. The thermal velocity
of the gas molecules, Maxwel-Boltzmann statistic.
Volume processes and transport of gas, diffusion, viscosity of gas, thermal conductivity of gas.
The gas transport through the vacuum pipes. Gas conductance of Vacuum pipes. Ohms law in gas transport. The volume and mass flow of the gas. The different mechanism of the gas transport - turbulent, viscose, molecular, effusion.
The limit pressure of the vacuum equipment. Pumping speed of the vacuum pumps and its measurement, the pumping down time. The influence of leakage and gas desorption.
The surface processes, adsorption, desorption, monomolecular and multimolecular layers, basic adsorption isotherms, saturated vapour pressure.
The basic principles of the gas transport. Transport and getter pumps. The pumping processes.
Mechanical pumps. Two Stage Mechanical pump. Roots blower. Turbo pumps. Diffusion pumps. Oil mist eliminators.
Getter pumps. Ion pumps. Diode Ion pumps. Titanium sublimation pumps. Diode and Triode Ion pumps. Cryopumps. Sorption pumps. Molecular sieve .
Pressure measurement (absolute and relative). Torricelli tube.U- tube. Thermocouple Gauges. Pirani Gauges.
Ion Gauges. Cold Cathode Gauges. Alfatron. Penning Gauges. Design of the triode Ion Gauge. Alpert-Bayard and Helmer-Hayward tube design.
The basic principles of vacuum equipment design. Technological processes in low pressure gases.

Aims

Acquirement of the knowledges about modern vacuum technics for use in electronics, in electrotechnical and mechanical industry

Specification of controlled education, way of implementation and compensation for absences

Laboratory practicum. Numerical practicum.

Classification of course in study plans

• Programme EEKR-MN Master's

branch MN-MEL , 1. year of study, winter semester, 4 credits, optional specialized
branch MN-EVM , 2. year of study, winter semester, 4 credits, optional interdisciplinary

#### Type of course unit

Lecture

13 hours, optionally

Teacher / Lecturer

Fundamentals seminar

12 hours, compulsory

Teacher / Lecturer

Laboratory exercise

14 hours, compulsory

Teacher / Lecturer

eLearning