*)N.B. if there are students who do not speak Portuguese the language is English.
This course aims to provide students with a broad knowledge in physics and technology of vacuum and cryogenics and allow a first contact and experience with different vacuum systems, so that students can, in future operate, acquire, assemble and maintain these kind of systems. Rather than providing a detailed training on fundamental physical processes involved, it is intended to contribute to an essentially practical and technological training in the operation and selection of different vacuum equipment and identifying the limitations that can be found in a given system.
Part I Basic principles of physics and vacuum technology.
Vacuum concept, properties and applications.
2. Properties of gases. The kinetic model.
Molecular density, pressure, mean free path,
incidence of molecules on a surface.
3. Vacuum system key.
3.1 Gas transport in a vacuum system.
3.2 gas flow schemes: turbulent, viscous, molecular and intermediate.
3.3 Conductances of the connecting elements in a vacuum system.
3.4 Time evolution of pressure in a vacuum chamber.
4. real vacuum system.
4.1 last pressure; real and virtual leaks; return flow.
4.2 Degasing of surfaces in vacuum; desorption; diffusion from the interior of the material; permeability; vaporization.
4.5 Different materials used in vacuum systems.
Part II Production and vacuum measurement.
5. Production vacuum.
Mechanical pumps and turbopumps. Steam pumps: ejector, and dissemination. Fixing pumps: absorption, adsorption, ionic and cryogenic. Pumping systems. Accessories.
6. Vacuum measurement.
Mercury gauges, mechanical; Thermal conductivity and ionization.
7. leak detection.
Detection with vacuum gauges and ion pump. Leak detectors.
8. Analyzers waste gas / mass spectrometers.
9. Comparative analysis of the costs for a vacuum system.
Costs of acquisition, operation and maintenance of equipment.
Part III Practical training.
1. Production vacuum.
1.1 vacuum systems operation turbomolecular, diffusion, with ion pump, adsorption pumps.
1.2 Operation of thermal evaporation, thin film deposition.
2. Vacuum measurement.
2.1 Operation with gauges of Bourbon and capacitive, Pirani, Penning and Bayard-Alpert.
2.2. Operation mass spectrometer quadrupole
3. Maintenance of a high vacuum system.
Disassembly, cleaning, installation, operation and leak detection.
4. Practical work with report presentation.
4.1 Study of the mechanical pump characteristics.
4.2 Effect of the pumping conductance.
4.3 Study of the diffuser pump characteristics.
4.5 Determination of outgassing rate (q½) of some materials.
4.6 Kapton permeability constant Determination for He and Ne.
Generic skills to reach
. Competence in organization and planning; . Competence to solve problems; . Capacity of decision; . Competence in autonomous learning; . Adaptability to new situations; . Competence in working in interdisciplinary teams; . Critical thinking; . Competence to communicate with people who are not experts in the field; . Creativity; . Competence in applying theoretical knowledge in practice; (by decreasing order of importance)
Teaching hours per semester
total of teaching hours
Laboratory or field work
Bibliography of reference
A Users Guide to Vacuum Technology, J.F. OHanlon (IBM Thomas J. Watson Research Center), Wiley-Interscience publication, John Wiley & Sons, Inc., New York, 1980, ISBN 0-471-01624-1
Tecnologia do Vácuo, A.M.C. Moutinho, M.E.F. Silva e M. Áurea Cunha, Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, Lisboa, 1980.
The fundamentals behind the diagrams and drawings are discussed in lectures. Whenever possible use is made to the presentation of theoretical and practical examples for better understanding by students.
Some practical classes have a demonstration purpose, so that students make contact with the operation of the various vacuum systems.
During the laboratory sessions the students are supposed to operate the vacuum systems independently, after a briefing concerning the procedures and the aims of the proposed work.
Laboratório com sistemas experimentais de alto vácuo baseados em bombas difusoras (Bomba difusora, bomba mecânica, medidor de baixo vácuo e respectivo controlador, medidor de alto vácuo e respectivo controlador, válvula de alto vácuo, válvulas de vácuo, válvula de agulha) Utilização/demonstração de equipamento avançado de vácuo existente nos diferentes grupos de investigação do Departamento de Física: