Termionski efekt i njegove primjene

master's thesis

• Title (english): Thermionic effect and its applications
• Author: Eva Poljak
• Mentor: Damir Veža (mentor)
• Committee member: Damir Veža (predsjednik povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Committee member: Ivo Batistić (član povjerenstva)
• Committee member: Damir Pajić (član povjerenstva)
• Committee member: Dalibor Paar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2017-10-09, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Termionski efekt je pojava emisije elektrona iz metala uzrokovana dovođenjem toplinske energije metalu. Broj elektrona koji napuštaju metal jako ovisi o temperaturi kao i o vrsti metala i dobro je opisan Dushman-Richardsonovom jednadžbom. Do njegovog otkrića je došlo kroz niz istraživanja pojava koje su sve zajedno dale sliku modela koji imamo. Zato je njegova povijest usko povezana sa povijesti fotoelektričnog efekta. Suštinski se promatrao isti fenomen samo izazvan na drugačiji način. Sintezom svih otkrića, uključujući značajne istupe Einsteina, sa fizikalnom interpretacijom fotoelektričnog efekta, i Sommerfeldove primjene Fermi-Diracove funkcije raspodjele na elektrone, oformljen je model kojim je objašnjena termionska emisija. Ona danas ima širok spektar primjena. Princip je rada za posebne detektore visoke osjetljivosti korištene u atomskoj laserskoj spektroskopiji i također za termionske konvertere energije koji obećavaju vrijednu primjenu na svemirskim letjelicama. Možemo je smatrati početkom tehnološke revolucije jer je upravo razvoj elektronskih cijevi korištenih u radio-tehnici neposredno doveo do potrebe za razvojem tranzistora, a time i tehnologiji bez koje danas ne možemo zamisliti funkcioniranje modernog svijeta.

Abstract (english)

Thermionic emission is the thermally induced flow of charge carriers from a surface or over a potential-energy barrier. This occurs because the thermal energy given to the carrier overcomes the work function of the material. The number of freely moving charge carriers in the metal, also known as electrons, that have sufficient energy to leave its surface is well described by the Dushman-Richardson equation. The history and the discoveries made by scientist investigating the photoelectric effect are closely related to the history of thermionic emission. The only discrepancy is the method via which the sufficient additional energy is provided. The key contributions were made by Einstein and his interpretation of the photoelectric phenomenon and Sommerfeld and his application of Fermi-Dirac statistics to the problem of moving electrons inside the metal. The ways in which we benefit from the discovery of the thermionic effect are many. Today they are used in special high-precision detectors for atomic laser spectroscopy. They also hold much promise as the future power suppliers of additional energy in spacecrafts through the technology of thermionic energy converters being developed today. Lastly, we have the discovery of the effect to thank for the electronic revolution and the world as we now know it. Had it not been for the discovery of electronic tubes used in pioneering radio broadcasting, the need for developing transistors, pillars of our technology today, may have never been realized.

• Keywords: termionski efekt
• Keywords (english): thermionic effect
• Language: croatian
• URN:NBN: urn:nbn:hr:217:209584
• Study programme: Title: Physics; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike (magistar/magistra edukacije fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-10-13 11:52:17